Bert teaches the Kalos techs about zone damper systems and how to work on them without being intimidated by them.
Zone damper systems have a zone panel, usually near the air handler, where 24v goes in and 24v goes out. The zone panel controls the dampers, which can open and close depending on where we need to send the supply air; the dampers can close when we don't need to send air to a certain zone.
We typically encounter damper motors of two designs: spring or power-open/power-close. The latter tends to be much more common in modern zone damper systems. A control system will have common, open, and closed terminals.
A spring motor may have a wire run between common and closed; it doesn't need to be connected to the open control because the spring will open it instead of power. When the system is not calling, the dampers will be relaxed, so they will be open.
Dampers also can't open or close properly unless the set screw has been tightened all the way down. You can typically get an idea of how well a damper is opening or closing based on how the air resistance sounds; if the damper is working properly, the sound will change a bit.
When installing a damper motor, you need to know the orientation of your damper and make sure that the damper stops spinning when it's supposed to stop. The size of the damper rod also matters and tends to vary by manufacturer, so you need to pay attention to get the proper repair parts.
Unlike the spring motor, a power-open/power-close motor will use common, open, and closed terminals. You can disengage the damper motor and see how freely the panel spins when you spin it yourself. If it spins freely, then you'd be able to rule out a panel jam diagnosis and could focus on the motor.
Damper systems need to be powered by a different transformer than the A/C system's transformer, so you'll have two transformers. The air handler may connect to common (which is a ground) and the R terminal on the thermostat, but the damper system's terminals may connect to the actual damper system; common is NOT the same as on the A/C system. However, the staging on the damper panel needs to match the motor staging.
Many damper issues can be understood without going into the attic. You can start one zone and check to see if air is coming out of the vent. Then, turn zones on and off as necessary to see which zones are and aren't receiving the airflow they need. Once you have an idea of the problem areas, THEN you can go into the attic.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
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I'm going to talk about zone damper systems, there's a lot of fear that can be felt when you show up as a new technician to a zone. Damper system, that's having issues even if you've shown up and the real issue with the system is that it's a failed capacitor. You almost always have a customer that is unsatisfied with their own system, because there's just so many problems that can happen or confusion on how they even work so knowing how they work, explaining that and being able to diagnose, what's wrong is kind of intimidating until you Get to to learn them first thing to say about a zone system is our zone panel is set up somewhere, usually pretty close to the air handler, hopefully, sometimes inside closet inside laundry room zone panel as complicated as it looks and as many options as you might Have on it, it's still just 24 volts coming in 24, volts coming out, all you need to know is basic understanding. How does it work? What is it actually going to do and you'll be able to pull out your meter and find out? Is it? Is it actually doing its job right, hopefully, you're going to have a better understanding by the end of this class, how the zone panel works so first of all zone panel controls zone dampers different areas in your house.

If you had a home that maybe you have upstairs and downstairs on the zone system, the purpose would be that the ductwork has one of these in it for those two areas. So all the work in your ac come comes out of the supply and deads into one zone. Two zone: three zones, whatever you have the air goes into these zones before it goes anywhere else into these zone. Dampers right.

If you have one that's separating your upstairs or your dance cell, stairs or purposes, you could power it closed in an area you're not using it, and then the area that is calling for air, like maybe downstairs, needs heat, but the upstairs is already already warm enough. The upstairs damper closed, no airflow is going into the ductwork, but your ac is still running airflow's. All going downstairs right. So in order to make that happen, we have to have a control system damper panel and control control motors for these damper panels too.

So you here are your two common, i'm going to start out with the motors and as i talk about each element, if anybody has like common issues that you've seen with these things just bring it up for the help of the whole class. If i don't okay, so we have two different motor designs here. Does anybody know what the difference is between these two yep a little more and then there's like a spring open, okay, spring power, open power, close versus spring yep? So this one right here, this uh this damper is going to spin. Let me give myself a leverage, pull.

We have a set screw here, so this damper is going to spin closed when it gets 24 volts. So this thing powers closed, but when it's open, when it's time for the damper to open up it uses a spring. So this is on a spring, so you're going to spin close and then the spring force it open when the voltage is off, and so the important thing to note about that is that when you have a control damper system, it's going to have listed on here, Controls for our motor zone, damper you'll, have a common, an open and a closed. So, on a motor like this, you would have a wire that goes between common and closed powering this right, so that when it's calling for it to open, there's, not actually a wire connected to this.
It doesn't need that function here, because this one's going to use the spring to open. When it's calling for it closed, then it'll pull the motor shut, and so then the motor is working against the force of the spring. It will only stay shut when you have upstairs. Let's say this is your downstairs damper upstairs calling for air, but the downstairs thermostat is satisfied.

So then, your zone panel is going to shut this and hold it shut until everything satisfies and the system shuts off and the way that they rest the way a spring system rests. It just drops voltage to everything and all your panels open. So when your system's not calling anything, don't expect to find your dampers closed, you expect to find them open whenever the system's satisfied. It's not calling for anything.

The resting position for a damper is open. Common issue is that this has been installed, but the set screw hasn't been tightened enough, so it starts slipping slides onto here and then your set screw comes in and hits this right. If this is spinning like the motor is actually working but we're slipping our damper's, not spinning right and even if it works a little bit like maybe the first few times you tested it when you installed the motor, if it's not tight enough over time, it starts Slipping and every time it turns it a little bit more and then it's not opening and closing all the way right ways that you'll find that problem. First of all, you're there's gon na the customer complaint is gon na, be, it seems like the damper is not working consistently.

Sometimes it works. Sometimes it doesn't or maybe it's slammed shut. It's not working at all and you can't just assume. Oh, i got a failed motor because i got power.

I can hear the power working, but my damper's, not spinning right. You need to test for things like this. Is my set screw all the way down. Last time i diagnosed this.

I noticed it because you should normally hear when you have it turned on. You should hear the resistance of the airflow when this thing starts. Closing it's really loud like right here. It's really loud as the air is trying to whistle through this thing closed when it opens all the way, then the static pressure right here is relieved.

It's not as loud you'll also hear the flex like crinkle yeah, so you'll often hear the flex past the damper. It relaxes and then when there's actually airflow coming in it'll push up real quick. So then that's another way that you can tell without cutting in to this and removing it and looking at it operating. So i could hear that my motor was trying to spin, but my damper wasn't because there wasn't a change in that in the sound or something like that, and that just made made me immediately look at okay.
How loose is this and you can hold? You can get a view down here which can be hard to, but you can look and see this spinning, but not this underneath spinning or you can take it off and you'll see a skid mark where it's been slipping. So i was last time i had. That is because we had quoted a new motor that had only been replaced a month ago. Somebody had quoted as fail, and i went there and just found a real basic problem like that.

It was me, quoted my own motor. No, it wasn't me, here's the other other type of damper system. It has no spring, so you have a common power, open power, close pretty basic, understand that um. A lot of these that are like this they'll have different functions like you have to disengage.

If you want to test your damper so maybe by hand you get up there and you're wondering, is the motor failed or is my damper jammed? You disengage your damper motor and you spin, and you can just by hand you can see how how well does this thing spin freely when damper panels spin freely? Okay, then my issues, probably with my motor, not actually the panel jamming right, but if you don't know about that, you're going to sit here pulling on this and nothing's going to happen, whereas the the spring-loaded kind of will just spin by hand you can just grab It and spin it power, open power close another major difference is that you know your dampers. Here's a couple different designs and this one shots at a 45 degree angle and opens and then comes to a shut position again, so that could be kind of confusing if you're, installing a new motor, you actually need to know the orientation of your damper and make Sure that when it shuts that this thing stops spinning here, when you're installing a damper motor a lot of these control on off or this one as well, they have different places that you can set your damper to stop spinning. So if i push this down and turn it, my damper is only going to spin this much until it hits the stopping point there's times, and this has that set screws on this side. For the same thing, depending on your damper when you're installing a motor you're gon na put it in and if you just let it go, and it's spinning to open it'll open all the way until it hits something and it's actually closed.

And then you tell it to close and it'll spin all the way to close again so you're going to have to actually set your stopping point right here and make sure that as it spins and it hits that limit that you set on the open area. The other thing that i recently screwed up when i floated the system was that uh, the sizing of your damper damper rods, are different, so you usually have the two basic like this. The small ones are going to be the honeywell, usually some form of a honeywell motor. This is the newer design of the honeywell motor.
The old honeywells will just look like a little square box, so when you're quoting this, you need to actually make sure that you're taking the information off of the motor itself and giving it to our parts guide to quote so that the proper damper you can't just Order anything this is a universal damper that can fit a lot of different systems. However, it will not fit on this one. We found that out recently me and eli. The rod doesn't come up high enough for the universal clamp to clip onto so you'd have to buy like a damper rod extension, which apparently is a thing that you could get online or you actually buy the right motor for the damper right.

That's a much better idea: okay, so there's some basics with dampers and damper motors now on to damper panel. Well, the like for the damper panel. You need the correct panel for that motor too, because, like obviously with the power close, it's going to power close until they, like you, said they both open in a resting position, but with the power close power open. Does it hold the signal there or does it send it like some panels would send it.

Some panels will hold the signal at the motor yeah. So most panels will hold the signal. They'll. Send the signal constantly open or close whatever it's calling for.

There are some panels that only send it for about 60 seconds, which would be a sufficient time for your motor and then drop it and then right when you change the call, you change the function, it sends it for another 60 seconds, that's a rare panel. So almost all of them just hold a constant signal on here in either application. It's pretty much going to work as long as the panel is going to work. Almost all damper systems have the power on power close some of the older honeywell, which have the spring.

Some of the old, older honeywell uh damper panels, don't have the power open because they they think they're just connected to a honeywell motor that has spring open. So you do need to look at that um. If you were to try to quote a different design or try to mis mix, match a motor and in a system all right, so your damper system probably be easier. If i just draw this on on how it actually works, let's do a panel and then we'll have thermostat and a damper motor and equipment and power, and let's just throw in a sensor, okay, so right here we have equipment.

This is how it's listed. What is this guys? That's right, so equipment is what is: is the controls coming out to to power on the condenser special request, so we're going to have the same thing here: r y um, c g w and then our uh open close and our common and uh our two dat Sensor, dat which stands for anyone yep and then our 24 volts, which will have hot and common uh first thing you need to know about your damper system, is that it is powered and from a separate transformer than your ac system. So you're going to have an ac, ac transformer think about it. This way, let's do minus 12 and plus 12 volts, which together equal what yep so across the difference between these two is 24 volts right, and so our minus 12 is usually tied in with common and ground.
It's grounded somewhere. There's my ground symbol inside the air handler and then this plus 12 is going to come to our r on our equipment. So this is our air handler transformer. Then uh, you have a separate transformer same thing: common are we're gon na.

Have it power our damper system right, different power sources? Common on here is not the difference, is not the minus 12 difference or the 24 difference. I'm sorry the 24 difference of the red on here you're going to be able to mix these powers. So you can't just take y here, which was recently tried and jumper it to y in our equipment to bring on our condenser or our air handler. Why not? Because that y is powered from the plus 12 of this transformer, but it's it's at uh or i'm sorry.

This y is powered from the plus 12 of this transformer, but the common for our contactor or our equipment is connected to the -12 of this transformer. So it's not actually compatible they're, not actually going to pull in a contactor. It's not actually the 24 volts difference between the two lines of that transformer you're using separate transformers. If you had identical transformers, you could tie them in together, so you would tie common and hot and red in both commons tied to ground and red could come into here and red come into here, and that would actually work identical transformers.

If you were installing a new system, you'd have to take the air handler out of the new system or have the identical one. That's in there use two truck stock because those are going to be identical. That's a big hassle for no reason, but that's what you could do. This is how this works.

The power that comes in here off of a separate, oh yeah. Anybody know why you would use a separate transformer. Why are they doing that? Amperage break what okay yeah, so you could break you could damage this transformer because the amperage would be too high you're trying to pull multiple motors. You could have multiple motors if you do have a short shorten here again it is overwhelming, but it's the same system of isolating you're going to disconnect part of your equipment and start reconnecting one thing at a time and finding out where this short is any questions.

Any important common issues that i haven't addressed, i believe those honeywell dampers can be power open file closed as well; okay, not this one, but it is wrong. Really you snap off that little piece in the center and then it's now powered it says optional enables green, led it's not just powering a light. You put a terminal inside there and play snap it off good snap it off now. Oh, i can snap it off.
I understand i've seen them wired up, but it would be so you can actually see the lights power up. No, we did probably didn't, then, if it actually well the reason i replaced that whole thing was because it was already wired that way, but it wasn't closing all right. So i assumed it was not closing because of a spring issue. It could have been a power issue.

The whole damper system got replaced too because there was actually issues with the board. It was repeatedly calling both zones at the same time, whatever you replace, open and close, and it's a two-stage system. They have to make sure that's the truth. Yes, yes, i made that mistake of ordering.

This goes back to what sam was saying talking to our repair guys, i ordered i had our repair guy order, a two zone damper panel without making sure that the one he ordered actually had also two stages, because our equipment was two stages so, like this damper Panel zone did not get used and that's because we only have a y, we don't have a y one y two. We don't have so communicating and following up being like okay, what panel did you order? Because i could just say: order: honeywell, two zone damper panel. I need to be more specific with that. He doesn't know what i'm looking at.

What equipment does go back to that? Just wanted to give a couple, quick tips that have helped me in diagnosing a lot of damper issues can be understood or or a lot of diagnostic can be done without climbing into an attic and staring at a damper motor. I think it's important that you know how they should be working in the way that the customer is going to experience it. So you come inside and you're going to turn on and check multiple dampers turn on your thermostat for the zone. You want to test get a ladder out, see if there's air coming out.

When you turn on that zone, then you're going to turn on both zones. Is the air coming out in the other zone so like? If you have the one calling and the other one not make sure go up there with the ladder make sure the other one doesn't have air coming out, it's not calling, but the downstairs is upstairs, is not calling should be no air coming out of the downs Upstairs and what this will do is help you know where to go to next before you climb up in the attic you've already tested several things, so you understand what's not happening and what is happening will make your job a lot easier and you can also find Out that everything's actually working properly that way too, if you bring on both thermostats, both zones calling and air is not coming out of one zone. You probably have a damper motor, that's failed shot or stuck i've seen where the set screw. That comes off of here, the low voltage wiring was caught in the screw and it was just twisted or the duct work was all twisted around there, so it was experiencing a lot more resistance throughout the years.
Maybe that's what caused the motor to fail? Those kind of issues you go up into the attic and you find so you do - need to go, look at your motor and actually make sure it's working when you have a real problem, but a lot of times you can find out hey. This is actually working. The way it should be and communicate to the customer what to expect maybe answer the questions on what they're experiencing that they think is unusual or weird. Just by using your ladder feeling the air and working with the thermostat, you can easily lose all motivation and patience because you spent 30 minutes in the attic before you actually tried functioning everything from down in the house and you're now, you're, really hot and upset, and Your mind's, not in a good place to diagnose, go into the attic last another thing that a service call that i got confused on was i had the thermostat, so i had the unit sitting o, but then o wasn't going to my condenser because some of those Panels come with like a setup, so you have to go in and select to energize.

Oh yeah, that's good! That's good! So if you'll have a heat pump set up here, some will have the o and the b for your root and ream equipment. That would be powered differently and they will often have either a digital display or they will have toggle switches or a jumper, and you have to get the install manual to make sure you're setting that up properly. But what this does is it tells our board. What type of equipment we have hooked up to it if it has a heat pump hooked up to it? The board actually needs to know that that when it gets a call on w for heat, it's not just calling our emergency w on.

It needs to also power appropriately or drop power appropriately to the heat pump, call y and then maybe call our backup p. It's based on a either y one or y two hooking up or a timed. You can actually set that up in the board too. Call on our backup key as needed as well, so it needs to be able to.

Whereas if this zone system was hooked up to a furnace, it would still get the call on w. It would know: okay, we're hooked up to a conventional setup. So when i get a call w i'm just calling heat on w, i'm not calling y in green and b or or or that so yeah, that's that's a common problem. If you're having issues with your heat pump setup, it could be your board, a more basic board setup that doesn't have configuration built into it.

Your thermostat will need an o wire in order for this o to be energized or de-energized, but any board that has a configuration set up. You can actually hook up the thermostat conventional, where it's only just called w, and as long as it knows, it's a heat pump whenever w calls it energizes or de-energizes, oh appropriately, but yeah ronnie's solution was found in the install manual or knowing how to con configure. Here, to set up 24 volts out in 24, volts out you'll be able to figure out your issues yourself, a little better now. I hope, thanks for watching our video, if you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come out, hvac school Is far more than a youtube channel, you can find out more by going to hvacrschool.com, which is our website and hub for all of our content, including tech tips, videos, podcasts and so much more.
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One thought on “Zone damper systems”
  1. Avataaar/Circle Created with python_avatars Akroppoli says:

    Thanks 🙏

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