Wire thermostat to control zone damper?

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Old 11-17-14, 07:50 AM
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Wire thermostat to control zone damper?

I'm trying to find out if it's possible to use a simple wall thermostat (setpoint only, non-programmable) to control a normally open zone damper like this one:



The idea would be that when the thermostat setpoint is higher than the room temp (sending a call for heat), that the zone damper would close and remain closed until the setpoint is reached, at which point it would release and reopen. What I don't know is whether or not a simple thermostat would send the correct signal or be compatible at all with a zone damper.

What I'm trying to do is use the zone damper to regulate the heat from my wood furnace. I have an Englander furnace that is integrated into my home's ductwork. It works great, but is really oversized for our home and can easily cook us out of the house. What I want to do is control the amount of heat sent into the house by dumping excess heat into the unfinished/uninsulated basement when the house is at the correct temperature.
 
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Old 11-17-14, 12:31 PM
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Connecting a thermostat to a damper can certainly be accomplished.

Where are you going to get 24 volts? A separate transformer, a fan center, or are you going to get it from some other location?

If this is a good idea because of possibly creating a negative pressure condition in the living space might be something to consider.
 
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Old 11-18-14, 12:34 PM
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I'll just wire up a separate transformer-can one transformer and one thermostat operate two dampers simultaneously if wired in parallel so each sees the same voltage?
 
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Old 11-18-14, 05:49 PM
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Yes, a standard 40va transformer should easily power a stat and a couple of dampers.

Post the stat and dampers that you intend to use.
 
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Old 11-18-14, 06:07 PM
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http://www.grainger.com/product/HONEYWELL-Round-Damper-4XA32?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/4XA34_AS01?$smthumb$

This type of damper, one normally open, one normally closed.

http://www.grainger.com/product/HONEYWELL-Low-V-T-Stat-14A004?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/14A004_AS01?$smthumb$

Just a simple thermostat like this one. All I need is for one damper to close and one damper to open when the setpoint on the thermostat is reached and vice versa. I was told I would need relays to make this work, but I can't really see why.
 
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Old 11-19-14, 06:17 AM
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A relay would take the load off of the stat. I would use a double pole double throw relay for 2 dampers.

Your links don't seem to work.
 
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Old 11-19-14, 07:31 AM
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Ok I get it, so the thermostat is not really acting as the switch for the dampers, just sending a signal to the relay to do the switching. That makes sense.

Trying again on the links to the t-stat and dampers:

HONEYWELL Low V T-Stat,Stages Heat 1,Stages Cool 1 - Low Voltage Non-Programmable Thermostats - 14A004|TH1110DH1003 - Grainger Industrial Supply

HONEYWELL Round Damper,8 in.Dia. - Zoning Dampers - 4XA32|ARD8 - Grainger Industrial Supply

As for the relay, would this be what I need?

McMaster-Carr

Could you recommend a transformer?
 
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Old 11-19-14, 01:07 PM
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An 8 inch 24vac Honeywell damper is $116.00 on Amazon including freight. You can save $140 .

I would get a Honeywell TH5110D thermostat from there as well. It is a much better stat.

I wouldn't try to use that relay.
A dpdt relay with a 24vac coil is around 15 dollars and an Elk 24vac 40 va transformer is $18 on Amazon.

I would use a fan center instead of a separate transformer and relay for a more professional look. You would also need a 4x4 j-box.

I can post links tonight. I'm on a cell now.
 
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Old 11-19-14, 01:27 PM
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Thanks a lot-I really appreciate it!
 
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Old 11-19-14, 06:18 PM
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Old 11-19-14, 06:32 PM
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I wired it as if it was normally closed in my last post. Honeywell dampers come normally open (although this can be reversed).

It should wire more like this for normally open dampers...

Name:  FanCenter w dampers NO.jpg
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Size:  44.3 KB
 

Last edited by Houston204; 11-19-14 at 09:45 PM.
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Old 11-20-14, 05:42 AM
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Nice diagrams! Not to throw a fly in the ointment, but I was actually thinking of using one normally closed damper and one normally open damper so that with the power off, one would remain closed and one would remain open. This is also a safety feature so if the power ever goes out, the wood furnace dumps into the basement rather than into the ductwork, which could be a fire hazard with no fan running to circulate the air. Here's what I'm thinking:

Setpoint reached, no call for heat/power out/dampers deenergized:
[ATTACH=CONFIG]42080[/ATTACH]

Setpoint higher than room temp-call for heat/dampers energized:
[ATTACH=CONFIG]42081[/ATTACH]

If there's a better way to do this with two normally open or closed dampers I'm certainly open to that idea too, using both kinds just seemed to make the most sense to me.
 
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Old 11-20-14, 08:23 AM
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We would just use N.O. from the fan relay to both dampers if you want the living space damper closed and the basement open with a power failure. You will probably need to reverse the living space damper since they ship normally open. It is easy.

Cap off N.C. from the relay.(shown as an orange wire in my diagram)

Name:  FanCenter w opposite dampers.jpg
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Size:  44.1 KB

The way I had it both dampers would have opened upon a power failure.
 

Last edited by Houston204; 11-20-14 at 07:20 PM.
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