Installing Motorized Dampers in Basement HVAC: Will It Work?

[Jmiller78]

TL;DR Summary

I'm wanting to install some motorized dampers in my basement. Need help with some of the numbers.

I'm installing 4 motorized dampers in my basement HVAC, the motor on each unit is 24V drawing 6 watts at 0.25 Amps. I will be powering them from one 24V 40VA transformer. One temperature controller, that uses direct output and has a max output capacity of 10A, will be installed between the power supply and the dampers. My question is will this work without burning something up? Should i wire the dampers in parallel to keep the voltage the same across all the motors? And what does direct output mean on the transformer, does it just match input voltage and amps?

 

[russ_watters]

I have a similar setup in my basement and yes it will work. Yes you need to wire in parallel. Since you had to ask, it would probably be a good idea to draw a diagram so we can check if anything else is missing.

 

[Tom.G]

Summary: I'm wanting to install some motorized dampers in my basement. Need help with some of the numbers.

And what does direct output mean on the transformer, does it just match input voltage and amps?

Please post a link to datasheets for the transformer, the controller, and the motor; or a photos of the nameplate on each of them.

The "direct" output could mean that it has DC (Direct Current) output. The (older) damper motors I am familiar with were all AC (Alternating Current).

Cheers,
Tom

 

[Jmiller78]

Controller, The Duct, The Transformer

 

[artis]

Controller, The Duct, The Transformer

OK from what I understand the temperature controller comes in 3 types, they are all function wise the same the only difference is in the relay inside and how much voltage/current can it switch.

There is just one problem here. The XH-3001 you seem to have is meant to be powered by DC of either 12 or 24 volts, but the duct vent you have has a motor that powers from 24 Volts AC.
You need to open the back cover of your white temp controller and see , ideally check with a multimeter whether the input (red black) wires are electrically connected to either of the yellow and black wires , because if they are as in the videos I just saw then that means your temp controller output is DC not AC and that is a pain.

It's easy to get AC to DC but not so easy to get AC from DC.

Your duct seems to operate by a 24 VAC motor where probably the 24v input means the duct opens fully and any less input means the duct opens half way or so. But the input has to be AC it seems.
That duct I think works similarly to a electrically controlled car throttle valve where the car ECU sends PWM to it to control how much it opens.

If you had some electronics skills you could in theory separate the temp controller input power from the relay and use the relay simply as a switch instead of a switch that already has power coming out of it.
The way it stands now it seems to me your out of luck. For these types of ducts you would need a temp controller that can take in 24v AC and control it's voltage.

If you had the 220v version as this guy in the video below, then you could just attach the output to your transformer primary and the temp controller would just switch your transformer on/off from the mains side whenever it wanted to engage or switch off the duct and then just wire the transformer secondary 24VAC to duct motor directly.

Here is another video about your controller
Tell me do you understand , and please report back about what kind of controller exactly you have, maybe ideally open the back cover and take photos inside, and if possible measure continuity with a tester of your controller input and output wires

 

[Tom.G]

According to the datasheet, the Damper takes 15VA. Since you are using four of them, the transformer should be rated a little more than 60VA.

The datasheet is at:
https://cdn.shopify.com/s/files/1/0060/8659/0528/files/ZC206-SS-DS-0121.pdf?v=1610731510

Other than that, they all look to be compatible with 24VAC, which the transformer supplies.

Cheers,
Tom

 

[Jmiller78]

Alright, I understand, I would take it apart but it won't get here until tomorrow, but This one before the transformer would work, I take it. Also does wiring the duct motors in parallel make the most sense to keep the voltage at 24V?

 

[Tom.G]

Yes, that controller looks like it would work if wired before the transformer. You STILL need a bigger transformer to drive four dampers though.

 

[Jmiller78]

Yes, that controller looks like it would work if wired before the transformer. You STILL need a bigger transformer to drive four dampers though.

I believe it is referring to the output of the wall plug in transformer that comes with the damper, the damper itself should only use 6 VA, if you use S(VA) = I(A) × V(V) to calculate VA. I attached a pic of the transformer that comes with it below

 

[artis]

Alright, I understand, I would take it apart but it won't get here until tomorrow, but This one before the transformer would work, I take it. Also does wiring the duct motors in parallel make the most sense to keep the voltage at 24V?

Yes this is the one you should have got from the start , you could have also got one that can simply relay a supplied input to output. Then you could supply the controller input with your 24 VAC and it would switch your output of 24 VAC on and off.
I believe in theory you can redo your existing one, but that would require you to understand some electronics and I'm not sure where you are on that.

The controller board has a 24 volt relay already inside, it is just wired such that it already takes your controller power supply power and switches that through the relay to he output so the output is DC which is essentially the same DC you supply that controller with.
Instead you could just leave the DC for the controller supply and then make the controller relay switch a separate voltage. The controller only controls the coil of the relay, the contacts can be made to switch any provided voltage, doesn't necessarily have to be the controllers own DC power.
But as I said depends on your level.

 

[Jmiller78]

Yes this is the one you should have got from the start , you could have also got one that can simply relay a supplied input to output. Then you could supply the controller input with your 24 VAC and it would switch your output of 24 VAC on and off.
I believe in theory you can redo your existing one, but that would require you to understand some electronics and I'm not sure where you are on that.

The controller board has a 24 volt relay already inside, it is just wired such that it already takes your controller power supply power and switches that through the relay to he output so the output is DC which is essentially the same DC you supply that controller with.
Instead you could just leave the DC for the controller supply and then make the controller relay switch a separate voltage. The controller only controls the coil of the relay, the contacts can be made to switch any provided voltage, doesn't necessarily have to be the controllers own DC power.
But as I said depends on your level.

Thay makes sense, i would give it a try if i was in dire straights but i just ordered the one for 110/220, should be here tomorrow

 

[artis]

Thay makes sense, i would give it a try if i was in dire straights but i just ordered the one for 110/220, should be here tomorrow

ok , well for that you would simply add the controller output to the primary of your transformer the secondary of the transformer wire directly to the duct motors. Let us know how you do

 

[Jmiller78]

Got it all hooked up, the thermostat controller, then transformer, then a switch, then the dampers, works great, thanks for all your help guys