Standard thermostats replace Beutler specialized ones!

The Story

My house, built in 2005, has an HVAC system from Beutler (now Villara), with a gas furnace, A/C heat pump, and two zones (downstairs and upstairs). Each zone has its own Beutler digital thermostat.

Although in general our Beutler system has worked well, we had some problems with it:

• The Beutler thermostats have a non-standard digital interface, and you cannot replace them with a standard thermostat or a more advanced modern thermostat such as a Google Nest.

• In 2022 the thermostat schedules stopped working reliably and became erratic and undependable.
• Any time the power went out, it was necessary to reset the time in the system. The Beutler controller backup battery seemed to be dead, although I couldn't find a battery on the controller. (It may use a super capacitor).

My solution: I converted the system to use a different non-Beutler controller board made by EcoJay (ecojay.com) along with standard thermostats.

I describe that conversion here, in case you have a similar system and would like to do the same. If you have questions or problems with the project description, you can contact me through the normal hackster.io method (best) or via email at ted@tedtoal.net.

Step One: Project Planning

To start with, let's talk about the EcoJay controller.

EcoJay Controller

The company EcoJay currently makes three HVAC controllers called SmartZone controllers, two that support one or two zones (SmartZone-2L and SmartZone-2X) and the other supporting up to four zones (SmartZone-4X). If you have only one zone or just two zones like I did (upstairs and downstairs), either of the two-zone controllers should work fine. With three or four zones you would want the four-zone controller. And if you have SmartVent in your Beutler system, a special section discussing it follows!

The SmartZone-2L and SmartZone-2X controllers are similar. The main difference, from my reading of EcoJay descriptions, is that the -2X comes with a supply air temperature sensor, while that must be ordered separately with the -2L. That temperature sensor is NOT for sensing indoor or outdoor temperature. Rather, it is used to measure the temperature INSIDE the HVAC duct, and serves to help prevent fires. I would recommend using it.

This project description is not a replacement for the EcoJay installation instructions. The short and colorful EcoJay installation card is very well done and easy to follow. Read it over a few times carefully. Plan out the installation, make a parts list, and get everything you think you need ahead of time.

Also, there are several good You-Tube videos about installing an EcoJay controller. You may find that one of those serves your purpose better than this project! Check them out!

About SmartVent

My HVAC system also has the Beutler “SmartVent”, which allows fresh outside air to be routed through the fan and blown out the registers throughout the house, with return air flowing into the attic. The system lets you cool your house at night in the summer using only the fan and not the more expensive A/C system.

In this picture of the return air intake vent, you are looking up at the SmartVent damper plate, and a "SmartVent" label is also visible to help you identify this. In its normal position as shown, return air from the house flows into the furnace/fan, and the outside air is blocked off. When SmartVent is turned on, the damper plate rotates to change air flow so outside air flows into the furnace/fan and house air flows back out into the attic.

The EcoJay controller board does not support SmartVent as it worked with the Beutler controller. If you have a SmartVent and want to convert to the EcoJay controller, you may need to abandon the SmartVent system. Alternatively, you can take on the considerable challenge of building a custom SmartVent thermostat, which I did. I plan to document that project in a separate hackster.io project.

If you have SmartVent but are willing to abandon it and leave it disconnected, you can also use the two-zone EcoJay controller. But, if you have SmartVent and want to retain the option of building the custom SmartVent thermostat or trying to use some of the EcoBee fresh air equipment, you will need the four-zone SmartZone-4X controller, which costs an additional $100.

If you read the EcoJay four-zone controller description, it may sound like it can control SmartVent, but that isn’t true. It can sort of do it, if you also buy the EcoJay economizer fresh-air thermostat, but it still won’t work like Beutler’s SmartVent and is not compatible with it for these reasons:

• Its regular fresh air mode consists of bringing in fresh air for a programmed number of minutes every hour, not what SmartVent is about.
• Its economizer fresh air mode requires the EcoJay fresh air thermostat with outside air temperature sensor, and it then requires that one or both zones be programmed for desired cool temperature in order for it to activate the SmartVent damper and zone damper(s). This means that if the outside temperature is not lower than the house temperature, the A/C would turn on. I don’t use Beutler SmartVent that way, I keep the A/C set to about 83° but set the SmartVent cooling setpoint to 73°, which worked great with the Beutler controller but won’t work with the EcoJay controller.
• The EcoJay economizer fresh air mode requires that the outside temperature be no higher than 68° for the fresh air vent to open. I regularly use SmartVent when, for example, house air temperature is 93° and outside air is 83°.

Assessing your HVAC system

Next, take a close look at your HVAC system to understand it and look for problems and to get an idea about where the system gets its power. I'm presuming you know that your system is a Beutler system.

Thermostat

You might start with the thermostats. The Beutler thermostat I had can be pulled from the wall, leaving the base plate on the wall (if it is securely fastened) with a good pull on the lower edge of the thermostat. Now, take a good look at the cable. How many wires does it have? There should be four wires connecting to the thermostat. In my case there was one additional wire but it was not used and had been cut off so I had to look closely to see that it was there. It is desirable to have five wires available, as some thermostats need five.

Three wires, Four wires, Five wires

What do the different wires do? This is actually standardized in all home HVAC systems, and is easy to understand. The wires are usually 18- or 20-gauge solid copper (mine were 20) with colored insulation. The colors are also pretty much standardized. The simplest thermostat would have three wires:

• Red (R): 24VAC (24 volts alternating current), hot power wire.
• Green (G): Turns on FAN if this wire is connected to the red wire (try it!)
• White (W): Turns on the FURNACE for heat if connected to red wire

When air conditioning is present, there is a fourth wire:

• Yellow (Y): Turns on the A/C for cooling if connected to red wire

A fifth wire can be used when the thermostat requires power, since for power you need two wires, not just the red 24VAC wire:

• Blue (C, typically blue, maybe black): 24VAC common wire

Why do most older thermostats NOT use the 24VAC common wire? One reason might be that it would be easy for an installer to accidentally touch the red and blue wires together and short out the 24VAC transformer. This could burn it out, or more likely, burn out a fuse. Always be super-careful when moving around the blue wire to make sure it doesn't touch the red wire.

Note: Some systems have one red wire from a furnace transformer (RH) and another from an A/C transformer (RC), which go to EcoJay RH and RC terminals. If there is only one R wire, a jumper wire is used to connect both EcoJay RH and RC to the R wire.

HVAC Equipment

Take a look at your HVAC equipment. If you don't know where it is, you need to find it. Mine was in my attic, and I can't tell you how many times I've been up and down a ladder and moved the attic cover aside! Thankfully, a light switch next to the entrance provided plenty of light, so I didn't need a flashlight when I went up there, except on those occasions when I turned the power off.

You want to identify the equipment as best you can. You should be able to find:

• Furnace. It should have power going to it (mine was plugged into a 120VAC outlet) and a source of fuel (mine was a gas furnace with a gas pipe to it).

• Main supply air duct coming out of furnace and branching out to go to all the air registers in the house.

• Return air duct coming into the furnace from a large opening somewhere, with the HVAC air filter located near the beginning. In some cases there might not be a duct, the air might be pulled straight into the furnace from the room it sits in.

• Controller box located near the furnace, with lots of wires leaving it and going to the furnace, thermostats, and other things. Simple HVAC systems might have the controller located inside the furnace, but for a Beutler system such as we are talking about, there will be a separate small metal box (roughly 6" x 8" x 2"). Mine was mounted on a horizontal stud in the attic. In my case, the lid popped off easily when tugged from the sides. Carefully study and identify all the wires connected to the controller. Where do they come from? And, is there plenty of room to install the EcoJay controller in its place?

• Dampers located along the supply air duct, with wires going to them from the controller. A damper is simply a flap in the duct that acts like an on/off valve. Often a spring holds it open, unless the controller energizes the two wires going to a small motor on it, in which case it closes. In other cases a damper will have three wires and the controller must energize one way to open and a different way to close it. You should expect to find one damper per ZONE. If the controller wants to heat zone 1, for example, it would activate the zone 2 damper to close it, so only zone 1 receives the hot air. You can tell which zone is which by looking at where the ducts go from the damper, and looking at the labelling on the controller where the damper wires connect.

• Air Conditioning Evaporator is located along the supply air duct, usually just after the furnace, with pipes leading from it to the A/C unit outside the house.

• Air Conditioning Compressorand Condenser is usually located outside next to the house, with a control wire running to it from the controller.

• Beutler SmartVent, when equipped, can be seen as a very large duct entering from the roof into a big box atop the main supply air entry point, with the supply air duct leaving that box and going to the furnace. Inside the box is the SmartVent damper, and there are control wires going to it from the controller.

HVAC Power and 24VAC Transformer

All HVAC systems are powered by 24VAC, not by the 120VAC power that comes out of all your electrical outlets. The reason is probably that the lower voltage is much safer, especially considering that it goes to the thermostats, where a homeowner might touch a wire.

The 24VAC is produced by a transformer that receives 120VAC input and produces 24VAC output. In my case, this transformer was located inside the furnace, and that is likely to often be the case. My furnace was plugged into a standard 120VAC receptacle located near it in the attic.

Adding an Additional 24VAC Transformer

The most important thing you need to do when assessing your HVAC system is to decide whether or not you will add another 24VAC transformer, and if so, what type and where it will get its 120VAC power.

Is an Additional Transformer Needed?

The EcoJay instructions say that the existing HVAC 24VAC power should NOT be used as the main power for the EcoJay controller, but instead, that you should install another transformer for this purpose. However, I question whether this is necessary, as the existing system uses the existing transformer to power the entire HVAC system including the Beutler controller and thermostats. I would think it would have no problem powering a different controller and thermostats.

It isn't easy to figure this out, though. The EcoJay installation instructions describe how to estimate total 24VAC power required (in units of VA, volt-amperes), but it is possible your furnace transformer powers other things not accounted for in the EcoJay instructions.

An easier way would be to just try it, but if it doesn't work you run the risk of burning out the existing transformer. If you can determine that it is protected by a fuse that you can replace, then you can assume the fuse will blow if too much power is drawn. To wire the EcoJay to the existing transformer, run the R and C wires from the HVAC equipment to the EcoJay PWR 24V and 24C connectors.

I decided to add another transformer.

Easy Way to Add an Additional Transformer

There are two choices for adding an additional transformer, an easy way and a harder way. The easy way is shown in one of the You-Tube videos I watched about installing an EcoJay controller. You can get 24VAC transformers with a power cord that plugs into a standard 120VAC receptacle.

For this to work, you need to have a spare 120VAC receptacle you can use, and it should be the same one that the furnace or existing HVAC transformer is plugged into, and MUST be on the same circuit breaker as the existing one.

In my case there WAS a spare receptacle on the same outlet box the furnace was plugged into. Unfortunately, I was not aware of these "easy method" transformers when I did my project, else I probably would have chosen one.

Harder Way to Add an Additional Transformer

I chose a harder way to add a transformer. I bought a 24VAC transformer that mounts directly to an outlet junction box through one of the knock-out holes in its side. I mounted it on the side of the outlet box into which the furnace was plugged, but because the size of that box was too small to allow for the transformer mounting screw to stick inside, I replaced the outlet box with a larger one. I used a wider and deeper box that was big enough to also include a switch so that I could turn the transformer and receptacle on and off. That was extremely handy in my subsequent work on the system, as I didn't need to repeatedly go out to the house breaker panel to turn off HVAC power.

If you are not comfortable with working on your house wiring, this method is probably not for you.

Make Your Plan for Additional 24VAC Transformer

In summary, you should choose a method of supplying 24VAC power to the EcoJay controller, one of:

• Use existing 24VAC transformer after testing if it will supply enough power
• Use a simple plug-in transformer
• Rewire and/or replace existing receptacle outlet box with a larger one that has the transformer mounted to it and a switch for turning off receptacle power.

If you choose to install a transformer, there are two vital issues to consider when choosing it:

1. Get a transformer whose power rating is sufficient for your system. Transformer power is measured in VA (volt-amperes). The EcoJay installation guide gives instructions on how to estimate the VA you need from your transformer. Get a transformer that supplies at least that many VA. If the VA of a transformer is not listed but the current capacity in Amps (amperes) IS listed, you can calculate VA from the following equation:

VA = Volts X Amps x 1.25
For a 24VAC transformer, use 24 for Volts.

It is best to err a bit on the side of too many VA for your needs. In my case I added an additional 5VA (overkill) for the Custom SmartVent thermostat I designed and built. A common transformer size is 40VA, which is probably sufficient for most home systems.

2. Make sure common and hot are marked somehow on the 24VAC side of the transformer. Many 24VAC transformers have two wires or two terminals that are NOT MARKED. You should avoid these transformers. When they ARE marked, the marking can vary: C and H, 0V and 24V, yellow/white and yellow, black/white and black, etc. When using two transformers in parallel, as would happen here on the EcoJay controller (one being the HVAC equipment transformer and the second being the one you install), it is absolutely critical that hot be connected to hot and common to common. If it is reversed, one or both transformers (or a fuse) will blow out. There is a way to determine which terminal is which on a transformer (see Appendix A - Transformer Phase), but I recommend avoiding this process and just choosing a transformer with marked secondary leads.

Other things you will need to go with the transformer:

1. Fuse, 2 or 3 amps. You can buy inline glass fuse holders at hardware stores that you can easily wire into the common wire from the transformer, but even better is to buy a transformer that has a built-in circuit breaker or fuse. Don’t skip this. I learned the hard way by burning out a transformer that had no fuse!

2. The wire from the transformer to the EcoJay controller should be 18-gauge 2-conductor solid copper cable, available at hardware stores.

Choose Thermostats

You should choose which thermostats to use to replace your existing thermostats. Check their installation instructions to see how many wires they require, to ensure you have enough wires in your existing thermostat cables.

Step Two: Part Sourcing

The full parts list is shown at the beginning of this project.

I bought my EcoJay controller, thermostats, and transformer on Amazon, and the electrical components needed to add transformer and switch to the outlet box from a local Lowes store. Although some local electrical supply shops had the appropriate transformer, most wouldn’t sell it to me because I don’t have a contractor’s license.

Step Three: Documenting the Build

I'll describe the actual installation process in these steps:

3A. Installing a simple plug-in transformer

3B. Installing a plate-mount transformer

3C. Removing old stuff

3D. Installing new thermostats

3E. Installing the EcoJay supply temperature sensor

3F. Powering up the EcoJay and setting parameters

3G. Connecting the EcoJay controller

3H. Testing the new system

I will also include some final appendixes giving additional detail on some aspects of the system for those interested.

Step 3A: Installing a simple plug-in transformer

If you choose the easy way to install a 24VAC transformer, then you have purchased a transformer with a 120VAC plug, you have an open receptacle on the same circuit as the furnace into which you can plug the transformer, and you have a length of 18-gauge 2-conductor solid copper wire cable.

Installation is as simple as running the cable from the transformer plugged into the receptacle to the PWR connector of the EcoJay unit, being sure to connect the COMMON wire from the transformer to the 24C EcoJay connector and the HOT wire from the transformer to the 24V EcoJay connector, using the red-colored wire for HOT. Since this is easy, you do not need to do it ahead of time. Instead, do it at step 3F.

Step 3B: Installing a plate-mount transformer

If you choose the harder (but better?) way to install a 24VAC transformer, then you have purchased a transformer with a plate mount screw/nut, you have an outlet box with a receptacle used by the furnace on which you plan to install the transformer (possibly replacing the outlet box with a larger one and adding a switch), you have the necessary electrical hardware and confidence to install it, and you have a length of 18-gauge 2-conductor solid copper wire cable.

I will describe the steps I took to install my transformer. You will need to make changes based on your specific outlet configuration. You can also refer to an earlier picture of my installed outlet box and transformer.

My furnace and the Beutler controller were in the attic, with the furnace plugged into a nearby electrical outlet on a simple junction box containing just a duplex receptacle. I replaced the small box with a larger junction box to which I added the transformer on the side and a switch to turn both the outlets and the transformer on/off. This made it unnecessary for me to make a trip out to the house circuit breaker box as I worked on my system (mainly, my SmartVent thermostat I designed) to turn the entire HVAC system off. It is up to you whether or not to add such a switch, or just wire the transformer in so that it is on whenever the HVAC circuit breaker is turned on.

I had been unaware of the plate-mount style of transformer. What you do is knock out a slug from the side (or lid) of an outlet box (“Handy Box”, "Junction Box") and mount the transformer on the OUTSIDE of the box.

In my case, I replaced a dual-outlet plastic junction box with a 4” x 4” metal box with an additional ring to add depth. There was too much wiring to stuff into the box without the extension. Adding it made it a whole lot easier to get all the wires inside. I also used two strain reliefs for the two cables already coming to the existing junction box, one coming from the house circuit breaker panel and the other going to a separate light switch and light bulb for the attic. I also added a switch on the left side of the outlet box, with the duplex receptacle on the right side, and the transformer mounted outside on the right side. The entire junction box was fastened to an attic 2x4 stud with screws. See the earlier picture.

Of course I turned off the circuit breaker while working on this, and used a good headlamp for light. (There is a light in my attic, but it is powered by the other cable coming out of the junction box, so when I turned off the circuit breaker, this also turned off the attic work light).

An important thing to know when working on house wiring is that usually the white wire is a common wire while the black wire is the HOT wire, and you connect the white wires to silver-colored screws/terminals on receptacles, and the black wires to copper-colored screws/terminals. On a switch you connect the black wire to either terminal, and connect another black wire to the other terminal and to the outlet or light it is powering. The bare copper ground wire is connected to green-colored bare metal ground terminals on switches and outlets, and to a ground wire attached to the transformer frame, if it has one. Copper ferules can be used to hold several bare copper wires together, crimping them with pliers or a crimp tool.

Usually a 3-hole receptacle is installed with the third (ground) hole on bottom, but it is sometimes conventional to flip it over and put the ground hole on top IF the outlet is turned on and off with a switch, which mine is. Therefore, I installed mine with the third hole UP.

I set up the switch to turn the transformer and the duplex receptacle on/off, but I did NOT make it switch the power going to the attic light. That receives power without going through the switch, so the light remains on if the switch is turned off.

Here is the schematic of my outlet wiring:

When finished wiring the outlet box, run the 2-conductor 18-gauge cable from the transformer's secondary terminals to the PWR connector of the EcoJay unit, being sure to connect the COMMON wire from the transformer to the 24C EcoJay connector and the HOT wire from the transformer to the 24V EcoJay connector, using the red-colored wire for HOT. Don't bother to actually connect the wires to the EcoJay controller yet. That will be done in step 3F. If the transformer doesn't have a built-in circuit breaker or fuse, add a 3A glass fuse in a holder inline with the 24VAC common wire coming out of the transformer. (I burned out a transformer before learning the importance of adding a fuse).

Step 3C: Removing old stuff

Before beginning to remove the old equipment, if you have a SmartVent damper, check to make sure it is closed to outside air. Do this by opening the vent containing the furnace air filter and look up into the SmartVent damper box. The damper plate should be visible and should be in the position shown in an earlier photo. You can see that air would flow from the house into the return air duct to the furnace. If it is not in this position, you need to make sure SmartVent is off and the damper returns to the correct position before taking out the old equipment.

When ready to remove the old equipment, start by turning off the power to the equipment, including furnace, controller, and whatever else. (If you installed or have a nearby switch to turn them off, use that, else turn off the HVAC circuit breaker at the house panel).

I first removed my old Beutler thermostats. They used a four-wire digital connection to communicate with the controller, but the cable had five wires in it, which is very common. The extra wire is good to have because many thermostats require a fifth wire, the 24VAC COMMON wire. I stripped the cable a bit and made five stripped wires of the same length for each thermostat. In my case it was not necessary to label the wires, because they are being re-used for a totally different purpose with the new thermostats, which use conventional wiring. If your cable only has four wires and your new thermostat(s) have five, you will need to replace it with a 5-wire cable. Hopefully that will be easy to do by firmly attaching new cable to old at one end, and then pulling the new cable through at the other end.

Next, I removed the Beutler controller. Disconnect all the wires on the old controller, but be sure to make a record on paper of all the wires as you disconnect them: their cable, color, and what connection they went to on the old controller. You must be absolutely certain which wires were previously attached to which terminals on the Beutler controller. I tried to use printed labels and that turned out to be a mess, they came unstuck. I recommend just recording the connections and labelling cables rather than individual wires. Make sure each CABLE going to the old controller is labelled somehow. Mine had been crudely labelled using a Sharpie on the 2x4’s on which the cables were hung and wrapped around NAILS.

Unscrew and remove the old controller after it is disconnected.

Step 3D: Installing new thermostats

With HVAC power still turned off, follow the installation instructions for the new thermostats. I mounted them in place of the old ones, connecting four or five wires according to colors listed earlier and according to the thermostat connector labels. Often the 24VAC COMMON connector will be labelled C, which stands for COMMON and not for some color.

Step 3E: Installing the EcoJay supply temperature sensor

My Beutler system did not have a temperature sensor in the supply duct, but the EcoJay -2X and -4X controllers require one and come with a temperature sensor.

With HVAC power still turned off, install the supply temperature sensor, an easy job. Drill a quarter inch hole in the main duct about 2 feet downstream of the A/C evaporator, in the side-to-side center of the duct, stick the sensor in, drill small holes for the two mounting screws, screw them in, and use aluminum HVAC tape to tape around it to seal it well.

I didn't photograph the hole I drilled or the sensor before putting it in place. Here is a photo of what it looks like after installing it.

I was concerned that when I drilled the hole, I might drill into something inside the duct. Actually, after drilling the hole, I saw that there was fiberglass insulation inside, and I didn’t know how thick it was or whether the sensor would reach beyond it. I used a straightened coat-hanger wire to poke down through the insulation, and by probing I found it was about 2” thick. Since the temperature probe was about 4” long, I figured it would reach down into the airflow and should be okay, and it seems to be.

Route the cable from the sensor to where the EcoJay will be mounted.

Step 3F: Powering up the EcoJay and setting parameters

Before wiring up the EcoJay controller to everything, it is useful to fire it up to ensure it works, then go through its parameter settings and change them to the way you want. To do this, you need to connect the two new transformer output wires HOT and COMMON to the EcoJay PWR input terminals 24R and 24C, respectively. You also need to connect the supply temperature probe installed above, because without it the controller complains that it can’t see the sensor.

After doing that, turn on the HVAC power to supply power to the new transformer. (The old controller is disconnected so the HVAC equipment should remain idle). Go through the EcoJay settings using the pushbuttons on the board and the instructions in the EcoJay installation guide. It took me a while to figure out how some of the stuff worked. The temperature limit settings refer to the limits for the supply temperature probe. The idea, I suppose, is to shut down the system before the duct gets so hot it starts a fire, when something is wrong.

After you get things set as desired, turn the power back off and disconnect the controller. Note that it holds the settings in non-volatile memory that is retained even with power off, so when you re-apply power, your settings will still be there.

Step 3G: Connecting the EcoJay controller

With HVAC power still turned off, mount the EcoJay controller in about the same place as the old controller. Connect wires in a similar way to how they connected to the old controller.

The EcoJay terminals are spring-loaded buttons, different from the screw terminals of the Beutler controller. You have to make sure each wire is pushed in far enough, then push the small push-down tab back upwards manually, and tug on the wire to be sure it is secure.

The EcoJay spring terminals don’t work if you try to put two wires in the same terminal hole. When I needed to do that, I put a single short wire in the hole and then used a wire nut at the other end of the short wire to wire the two or more other wires together with it. I had to do this with the 24VAC COMMON wire (coming from both furnace and A/C compressor and going to the EcoJay COM terminal) and the Y yellow/cool wire (also coming from both furnace and A/C compressor and going to the EcoJay Y terminal).

When you get the hang of using these spring terminals, they are easier to use than the screw-type connectors.

There will be several differences in the wire connections between old and new controller:

• The supply temperature probe installed above is connected. The Beutler system had no such probe.
• The Beutler system has an outdoor temperature sensor (connected to the OS R and W terminals), but the EcoJay does not use this, so these two wires are left unconnected. (I made use of it in the custom SmartVent thermostat I designed and built, a separate project).
• Connect the furnace and A/C equipment to the EcoJay equipment output.
• Connect the new transformer to the EcoJay PWR 24R (HOT wire) and 24C (COMMON wire) inputs.
• The two cables coming from the thermostats need to be connected to the EcoJay Zone 1 and Zone 2 thermostat inputs, which are labelled the same way as the thermostat, with the usual color codes. The 24VAC COMMON wire connection is labelled C.
• The zone dampers must be connected to the EcoJay Zone 1 and Zone 2 damper outputs, but not as you expect (see comments below on NC/NO vs CLOSE/OPEN).
• If you chose to use a 2-zone EcoJay and you have a SmartVent, then the three SmartVent damper wires remain unconnected (and you should have made sure the SmartVent was closed before turning off your system and replacing the controller; it will remain closed). Otherwise, connect them to the EcoJay Zone 4 damper outputs (see comments below on NC/NO vs. CLOSE/OPEN).

It turns out that the Beutler controller's labels for the damper outputs are in apparent conflict with the labels on the EcoJay controller. The correct way to move 2-wire damper connections is to move the Beutler 24C damper wire to the EcoJay damper COM terminal, and the Beutler NO wire to the EcoJay CLOSE terminal (NOT to the OPEN terminal!). This works for 2-wire spring-close dampers, which mine were.

If yours are three-wire dampers, you will have to try one way and if it's wrong, swap the OPEN and CLOSE wires.

It can be difficult to determine whether it’s working the right way. If both dampers are reversed, and you turn the system on and they remain closed instead of both opening, then no air comes out the registers, but instead builds up hot air inside the supply duct, until the temperature gets high enough that the temperature probe tells the EcoJay to turn the system off.

If you have SmartVent and the EcoJay 4-zone controller, transfer the three wires for the SmartVent 3-wire damper as follows. Move the Beutler 24C damper wire to the EcoJay damper COM terminal, the Beutler NO wire to the EcoJay OPEN terminal, and the Beutler NC wire to the EcoJay CLOSE terminal. (So in this case the O’s DO go together, and the C’s)

Step 3H: Testing the new system

After you’ve finished wiring up the EcoJay controller, turn on the power to the HVAC equipment and the new transformer and hence to the EcoJay controller. The controller board should light up. After a short bit, if your house needs heating or cooling, it should activate the furnace or A/C. Mine had been powered down for over 24 hours in the winter, and the house was down to about 63°. The furnace soon came on, and stayed on for a long time. It took over a day to get it warmed up.

Turning on the power will also power up the new thermostats, and they should now be fully operational. You will need to set the date and time and schedules.

You will want to test both the furnace and the A/C with both zones. The tedious, you can do this by changing the heating/cooling mode and temperature setpoint on each thermostat. Test each zone individually and both zones together. Make sure HVAC air is flowing out of the expected outlets at the expected times. If you have a SmartVent damper, check to make sure it is closed to outside air.

Appendix A - Transformer Phase

The problem discussed here is connecting together the outputs of two separate transformers, both 24VAC. One is the your existing HVAC transformer inside your HVAC equipment, and the other is the transformer you bought.

Note that you will not actually be directly connecting the two transformers. However, both transformers connect to different connectors on the EcoJay controller. It might be that the EcoJay is designed to isolate the two transformers so that regardless of how you connect them, the circuit works correctly and no transformer burns out. However, my assumption is that this is not the case, and that if you do not match up hot with hot and common with common when you connect to the EcoJay, that one or both transformers might burn out or a fuse or breaker might trip.

So, I believe it is crucial that you connect the two transformers to the EcoJay as follows:

• HVAC transformer HOT wire into Equipment RC/RH connectors on the EcoJay
• New transformer HOT wire into PWR 24V connector on the EcoJay
• HVAC transformer COMMON wire into Equipment COM on the EcoJay
• New transformer COMMON wire into PWR 24C connector on the EcoJay

You might wonder why this would matter, since the transformer outputs are A/C (alternating current), not DC (direct current), and therefore there is no + and - terminal on the transformer, the voltage just alternates. That is true, but at any moment in time, one terminal is + and one is - even though it is alternating!

Consider a pair of batteries that you wish to hook together in parallel to provide twice the current (same voltage). You would do this by connecting the two + sides of the batteries together, and separately, connect the two - sides together. If instead you connected + to - in both cases, you would be shorting the batteries together and they would rapidly heat up and burn out.

The same is true of two transformers, but the + and - polarity is rapidly switching because it is A/C.

We have the same goal here of wiring the transformers in parallel, so that we double the amount of power they provide, while keeping the voltage the same.

Side note: if your goal is to hook two batteries together in SERIES to provide twice the VOLTAGE with the SAME CURRENT, THEN the batteries are connected + to -, except for one pair of + and -, which are connected to the circuit being powered.

If both transformers are marked somehow to indicate which wire is hot and which is common, then it is easy to connect the wires properly. However, it is still possible that something could go wrong:

• The house electrical outlet and/or furnace connection to the house wiring might be incorrect, the outlet (or possibly the furnace) reversing hot and common 120VAC wires. Then, the 24VAC hot and common labels on one of the transformers would be incorrect.
• The house electrical outlet and furnace connection to the house wiring might use different 120VAC phases. The two separate phases coming into a house together add up to 240VAC, which is used for powering ovens and dryers. Each 120VAC circuit can be on either one of the two phases, and if the two transformers were on different phases and you tried to connect them together in parallel, probably something would blow out.

Therefore, it doesn't hurt to determine FOR SURE which of your transformer secondary leads should be connected to the furnace HOT wire and which to its COMMON.

Most likely the furnace is wired correctly and its transformer hot wire can be trusted to be the actual hot wire. However, the procedure described here doesn't make that assumption, and will enable a correct connection even if the furnace is wired wrong.

Since plus and minus can’t be used to describe the two transformer output wires, the terms I've used instead are HOT and COMMON. I also have seen PHASE and COMMON used. And I've seen transformers labelled R for hot and C for common, or 24V for hot and 0V for common, or using wire color or wire stripes to signal which wire is hot and which is common (In that case you need the transformer data sheet to know which color is which).

You might wonder what the distinction is between HOT and COMMON that makes them different on the transformer output. It has to do with the relationship of the input wires to the output wires on the transformer. The input side also has hot and common wires, and these are connected to the hot and common wires of the house electrical system, respectively. If you were to observe the alternating voltage on the transformer inputs and outputs, the alternating voltages would be in phase with each other when you are measuring from hot to common on both sides, but would be out of phase with each other if you were measuring from hot to common on one side and from common to hot on the other.

Using a multimeter to measure A/C voltages, there is an easy way to test two transformer 24VAC outputs to see if the hot and common wires on the two are matched together or mismatched. The method is the same as wiring batteries in SERIES. As mentioned above, when two batteries are wired together in series with + connected to -, the voltage for both batteries together is DOUBLED. On the other hand, if you were to connect + to + on the batteries, and then measure the voltage between the - sides, it would be ZERO because the batteries cancel each other out. The same thing happens with two transformers connected in series: if you connect the hot of one to the common of the other, the remaining hot and common will have twice the voltage. If instead you connect the two hots together and measure across the commons, or vice-versa, you will measure ZERO or close to zero volts.

So, to do the test and identify your two transformer outputs as HOT and COMMON, after wiring up your new transformer to 120VAC but before wiring its outputs to the EcoJay, start by turning off the HVAC equipment. Then disconnect the 24VAC hot and common equipment power wires from the existing HVAC controller (the Beutler controller). The hot wire is the one connected to the 24VAC input, labelled 24R on the Beutler controller, and the wire color is normally red. The common wire is the one connected to the 24V COM or COMMON input, labelled 24C on the Beutler controller. The COMMON wire color varies but is often blue or black. Disconnect and label these two wires as HOT and COMMON.

Next, wire your new transformer’s 24VAC outputs in series with the equipment transformer by connecting the equipment wire you just labelled COMMON to the new transformer output wire that you labelled HOT. Then, apply power to the HVAC equipment and to your new transformer and, using a multimeter set to measure AC voltage, measure the voltage between the equipment wire you just labelled HOT and the new transformer output wire that you labelled COMMON. Be careful! The sum of the two transformer voltages is around 50 VAC and this is enough to give you a mild shock, so avoid touching the wires, terminals, screws, or multimeter probe tips. Also, be careful not to touch the two 24VAC transformer output wires together, because this will short out the transformer and immediately burn it out!

If your multimeter measures somewhere in the vicinity of 48 VAC (it can vary quite a bit, say 45 to 55 VAC), this means that your labels on the new transformer wires are CORRECT.

If your multimeter instead measures near zero volts (it might not be exactly zero, say less than 10 VAC), this means that your labels on the new transformer wires are INCORRECT, and you need to reverse them, then try again to make sure it is now right.

That’s the test. Now disconnect the series connection and restore the equipment 24V HOT and COMMON wires to their original places until you are ready to switch over to the EcoJay.

What happens if you don’t do this and just wire the two transformers at random and hope for the best? If you are wrong, it is essentially the same situation as if you were to connect two batteries like that: plus of one battery to minus of the other, and then again with the other plus and minus terminal. You’ve then created a current loop, and the batteries will drive a high amount of current through themselves and rapidly deplete the battery, if not destroy it. With the transformers, if they are connected together wrong, they will drive a high amount of current through each other and one or the other or both transformers will burn out within a fraction of a second. I know because I did this with my first transformer before stopping to think. If you were smart and protected your new transformer with a fuse or circuit breaker, the fuse should blow or the circuit breaker will trip, and the transformers should be safe. So, that is another way you could test the labels.

Appendix B - HVAC Dampers

An HVAC damper is nothing more than a moveable plate inside a ventilation pipe, connected to a motor. The plate can either block airflow through the vent or allow it. Often a spring holds the plate in the open position where it allows airflow, and the damper is said to be open. If the damper motor is activated, it rotates the plate to block airflow, and the damper is said to be closed.

You might think the motor would open the damper and the spring would close it, rather than the other way around. However, in HVAC systems dampers are normally left in the open position when the system isn’t running. I assume this is a sort of safety feature, so that if the damper motor stops working and the furnace turns on, the air isn’t blocked inside the HVAC duct with no place to go, creating a fire hazard. So, dampers are only closed temporarily while another zone requires heating or cooling or ventilation.

When a damper is closed by a motor and opened by a spring, it has two wires that go to the motor, and is referred to as a 2-wire damper. Applying 24VAC across the two wires activates the motor and closes the damper.

Some dampers, instead of having a spring to open them, have motors that can go both clockwise and counterclockwise. One direction closes the damper, the other opens it. These dampers have three wires going to the motor, a common wire plus one wire for close and one for open. These are referred to as 3-wire dampers. Applying 24VAC across the common and open wires activates the motor to open the damper, while applying it across the common and close wires reverses the motor direction to close the damper.

You should determine, for each of your dampers, whether they are 2-wire or 3-wire dampers. This is easily done simply by either looking at how many wires are connected to the damper motor, or by looking at how many wires were connected to the old controller for each damper.

In my Beutler system, the dampers for the two zones (upstairs and downstairs) were both 2-wire dampers. The SmartVent damper, however, was a 3-wire damper.

Appendix C - Relays

HVAC equipment is generally activated by applying 24VAC to its control signal. For example, this arrangement would turn on the furnace:

“Furnace” above could be replaced by “Fan”, “A/C Compressor”, or “Damper” and the same thing applies, the 24VAC would turn the device on.

Controlling devices such as thermostats or EcoJay or Beutler controllers use a switch to allow them to only turn the device on when they want to. A switch is depicted with an angled line that represents a metal bar inside the switch that moves to connect the two sides of the circuit, thus completing the circuit so electricity can flow:

You can test this simple control arrangement yourself by accessing the wires to your thermostat. One is the 24VAC “R” (red usually) hot wire and another is a “G” (usually green) fan wire. Remove the “G” wire from the thermostat and touch it to the “R” wire, holding it in place. After a few seconds you should hear your system fan turn on.

The switches used in controlling devices are actually RELAYS. A relay is simply a switch that can be activated by a controller by having it apply a voltage to an electromagnetic coil inside the relay. The electromagnetic coil pulls on the metal bar inside the switch and moves it to the closed position to complete the circuit. Relays are used everywhere in HVAC systems to open and close dampers and to turn the fan, furnace, and A/C air compressor on and off. The reason for using a relay (instead of having the controlling device directly send 24VAC to the equipment from its own circuitry) is so that the electrical signals of the two interconnected devices (e.g. thermostat and controller, or controller and furnace) are completely isolated electrically and can’t interfere with one another.

A relay can be depicted like this, with the coil shown next to the metal bar it pulls on to make it touch the triangular contact point and complete the circuit:

In this diagram, energizing the relay energizes the furnace circuitry, causing the furnace to turn on. The relay has terminals labelled COM (Common) and NO (Normally Open) connected to the switch inside the relay. “Normally open” means that the switch is open when no power is applied to the relay.

Now replace the Furnace with a 2-wire Damper, and assume the controlling device is a controller such as the Beutler or EcoJay controller:

In this diagram, energizing the relay energizes the damper motor, causing the damper to close. The motor continues to be energized for as long as the damper must remain closed. As soon as it is deenergized, the spring opens the damper.

What if the damper is a 3-wire damper? In that case, what is desired is that one of the two damper motor wires is energized when the damper is to be opened, and the OTHER motor wire is energized when it is to be closed. It is always one or the other, either open or closed. How is this done with a relay? It is accomplished because relays have another contact inside them, so that when the electromagnetic coil is energized, the relay switch is thrown one way to complete one circuit, and when it is NOT energized, the relay switch is thrown the other way to complete a separate circuit. This new relay terminal is often labelled NC for “normally closed”, meaning the switch is closed when no power is applied to the relay. The two circuits share a common relay wire, the one shown as COM in the picture below.

This diagram shows the extra relay contact and how a three-wire damper is connected to the relay:

In this diagram, the relay has a new terminal labelled NC (Normally Closed) along with the previous COM and NO terminals. The NC terminal goes to the new switch contact that is closed when the relay is not energized (normally closed), completing the circuit between the NC and COM terminals. Energizing the relay connects COM to NO, which energizes the damper motor through the wire connected to NO, causing the damper to move one way. When the relay is not energized, the NO contact opens up and the NC contact closes again, which energizes the damper motor through the wire connected to NC, causing the damper to move to the other position. Note that the motor is designed to stop consuming power once it finishes moving the damper either open or closed.

There is a reason I didn't label the two red damper wires in the diagram above, one labelled CLOSE and the other OPEN. That is, I don’t indicate whether energizing the relay opens or closes the damper. You can connect NC and NO to the two red damper wires either way. One way, energizing the relay opens the damper, while the other way, energizing it closes the damper. And which way you want to connect it depends on whether you want it closed or open when the controller is not energizing the relay. I mentioned that normally a damper is left open when the system isn’t energized, so the usual wiring might connect the NO relay terminal to the CLOSE wire of the damper. however, the SmartVent 3-wire damper actually doesn’t even have a concept of open and closed! I will discuss this in a later appendix.

The relay terminal labels NO, COM, and NC, used in the electronics industry, thus refer to the normally-open switch contact (NO), the common side of the switch (COM), and the normally-closed switch contact (NC). The relay’s two states of energized and not energized are summarized as:

Relay off (“Normal” state):

• COM to NO: open circuit, no current flows
• COM to NC: closed circuit, current flows

Relay Energized ("Activated" state):

• COM to NO: closed circuit, current flows
• COM to NC: open circuit, no current flows

This is where the labels “Normally Closed” (NO) and “Normally Open” (NC) come from. Those labels are used in the electronics industry. However, the labelling is often different in the HVAC industry, in order to make it clearer which way dampers are to be connected to the controller. Unfortunately, the labelling is not completely standardized, which led me to some confusion, which I discuss in the next Appendix.

Appendix D - Beutler relay NO/NC versus EcoJay OPEN/CLOSE

One confusing thing about the labels shown in the diagrams in the previous Appendix on relay operation is that the COM connection on the relay is connected to 24VAC (red wire, R, hot) and is NOT connected to the 24VAC COMMON (black wire, COM or C). COM is being used to refer to two different things! Let's try to understand this better.

Redraw the previous diagram to show how the terminal connections to the relay appear on the controller circuit board, which has small connectors for attaching the wires coming from the other equipment:

The labels shown on the controller’s terminals above are what I find on the Beutler controller. They include a wire color designator letter too (R=red, B=black or blue, G=green, W=white), although this color isn’t necessarily followed when wiring up the system.

Notice that the three connectors for the damper don’t all connect to the three relay terminals. The 24C damper connector instead is internally connected to the 24C power connector, which is the 24COM wire from the transformer. So, the C in 24C refers to the common wire from the transformer, not the common terminal on the relay.

The third relay terminal, the COM terminal, is connected to the 24R power connector, which is the 24VAC hot wire from the transformer. The two damper wires for the motor connect to the NO and NC connectors, which are internally connected on the controller to the relay NO and NC terminals.

On the EcoJay controller, the damper connectors are instead labelled COM (in place of 24C), OPEN (in place of NC), and CLOSE (in place of NO). Why is NO (Normally Open on the relay) labelled CLOSE on the EcoJay, and vice versa? Let’s look at the connection for a 2-wire damper to understand:

In this case both Beutler and EcoJay labels are shown. EcoJay labels the 24R power connector as 24V. Either way, that’s the “hot” wire from the transformer (R, red, not the COMMON wire). They both use 24C for the transformer common wire. On the damper connector, EcoJay uses COM instead of 24C, but in fact it is internally connected to the 24C common power connector, NOT to the relay COM terminal!

The most important thing to notice is the label on the damper motor wire that goes to the connector labelled NO (normally open) on the Beutler but labelled CLOSE on the EcoJay. When the relay is energized, this wire carries 24VAC and activates the motor to close the damper. So, the EcoJay label is more accurate in terms of describing what that connector’s function is: to close the damper. The Beutler label instead properly describes the relay terminal the connector is attached to, but that may not be of interest to a person working on the HVAC system.

Likewise, the EcoJay OPEN label is more descriptive of HVAC functionality than the Beutler NC label.

Is the same true of the 3-wire damper? Well, as long as you know which of the three wires is the one that opens the damper, you can connect that to the EcoJay OPEN connector (Beutler NC connector), and connect the other wire to the CLOSE connector, and the EcoJay will control the damper properly.

However, things are different for the 3-wire SmartVent damper, and I describe this in the next Appendix.

So in summary, when moving from the Beutler controller to the EcoJay controller, swap 2-wire damper wires so that NO is moved to CLOSE and NC is moved to OPEN.

When you turn your system on after connecting the EcoJay controller, you want to check that each zone that is calling for heat or cooling has air coming out of its vents, and those zones not calling for heating/cooling do not have air coming out of their vents. If this is not the case, that zone’s damper is wired to the wrong EcoJay terminal (OPEN vs CLOSE). In my case I initially wired my dampers to the OPEN terminals because they had been connected to the Beutler NO terminals. When the system tried to heat the house (both zones initially wanted heat), no air at all came out of the vents, and the supply air temperature displayed on the EcoJay rose (because the air had nowhere to go) until the high temperature limit was reached, causing the EcoJay to turn the furnace off.

Appendix E - SmartVent 3-wire Damper

The Beutler SmartVent damper is unusual in that air can flow in either damper position. In one position, air can flow from the house interior into the HVAC main vent. In the other position, air can flow from outside into the HVAC main vent, and house interior air can flow back out the SmartVent into the attic. It is a clever design with the damper having a rectangular plate, and its two positions are like an X when viewed from the side. The SmartVent damper has no "closed" position!

The SmartVent damper is located directly above the grate that has the HVAC filter inside it. If you open the grate and activate SmartVent, you can watch the damper slowly change to the other position, which you might want to do before you disconnect the Beutler controller. Before wiring the EcoJay controller, open the grate and look at the SmartVent damper position, which is presumably in the non-outside-air position because SmartVent was probably not active when you turned off power to the system. You want to make sure that after you install the EcoJay and turn it on, the SmartVent damper remains in this non-outside-air position rather than changing to the outside-air position. If it does change, that would mean you need to reverse the wires on the OPEN and CLOSE terminals of the EcoJay zone 4 damper outputs. Strangely, with the SmartVent damper I did not need to reverse the NC/NO connections when moving to the EcoJay, even though with the 2-wire damper wires I had to move the NO wire to the CLOSE connector. Instead, for SmartVent I connected NC to CLOSE and NO to OPEN, and found that the SmartVent remained in the non-outside-air position as desired. What’s going on?

Consider this: although normally dampers are left open when the system is not active, from the point of view of EcoJay, the SmartVent damper, which they call a “fresh air damper”, should normally be left “closed”. Having it “open” implies that it is open to fresh air coming into the house, and for normal operation it should be closed. From Beutler’s perspective, it is open in EITHER position: in one position it is open to the inside air of the house, and in the other position it is open to the outside air.

Because of that difference in perspective, and because EcoJay chose to label their relay as they did (the relay is shared by Zone 4 and by the Fresh Air damper; it can be used for either depending on the thermostat type setting), from the perspective of the damper position rather than the relay contact position, their controller software must activate the fresh air damper relay normally, when fresh air is not desired. This means it is active most of the time, and if power went out, the relay would deactivate and the SmartVent damper would open to outside air (except that the power is out, so it can't!). That is backwards from the way their other zone relays operate, which are only activated during heating or cooling of a zone. This is one reason that you have to tell the EcoJay board, via the zone 4 thermostat type setting, that the zone 4 damper is used for fresh air. And this implies that the reversal of damper wires required for the other zones when moving from Beutler to EcoJay is NOT DONE for the SmartVent damper. The NO wire on the Beutler controller’s SmartVent damper connector is connected to the OPEN connector on the EcoJay, and the NC wire is connected to the CLOSE connector.

(Another reason the EcoJay software must know that zone 4 is being used for fresh air is that when the zone 4 inputs call for fresh air, the EcoJay knows it should leave the other zone dampers open, rather than closing them if zone 4 were an actual zone in the house).

The Beutler controller knows what SmartVent is and knows that energizing the relay to close the NO circuit will open SmartVent to outside air, so it does not energize the relay normally, and SmartVent normally stays in the inside-air position with the relay not activated. On the other hand, in fresh-air mode the EcoJay controller thinks of the zone 4 damper as an outside (fresh) air damper, which when open brings in fresh air. Since it doesn’t want it to be open normally, it energizes the zone 4 relay normally, to provide power to the CLOSE terminal of zone 4, keeping the fresh outside air damper normally closed. Hence, unlike the 2-wire dampers for zones 1 and 2, for the SmartVent 3-wire damper there is no reversal of connection.

So in summary, when moving from the Beutler controller to the EcoJay controller, on the SmartVent 3-wire damper, move NO to OPEN and NC to CLOSE.