Help choosing thermostat for water-heated 2-pole line volt heating.


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Old 09-09-07, 01:33 PM
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Help choosing thermostat for water-heated 2-pole line volt heating.

Greetings,

I live in a new contruction townhome with hot water heated in-wall heating (gas heats water, water piped to wall unit, fan blows air over water-heated elements) -- sorry I don't know the proper name for this type of heating.

I'd like to replace the ugly/inaccurate dial thermostats I have with digital programmable ones. The problem is I don't know how to determine if a given thermostat will work with my situation.

Here is what I have. Each of the in-wall heater units is one of these:

Turbonics, Inc.
Model: 4/5 WM
Series: 32597
115 Volt, 60 Cycle, 1.5 Amps
15 Amp Supply Circuit, unit load less than 2 amps

The thermostats have the following information on them:

Non-inductive rating
D22 125/250/277 VAC
22 Amps Double Pole
Wiring: 2 black wires, 2 red wires, one ground (bare) wire

So basically I have double pole thermostats. I know I can use single pole thermostats with double pole wiring by shorting two of the wires, but I'd rather not as with no "off" position the water is constantly being heated and drives up my energy bill (learned this the hard way by finally tracking down the one thermostat that was not fully off, wondering why all the vents were always warm to the touch).

I'd like to buy the Honeywell LineVoltPro 7000/8000 models, so my question boils down to would these work in my installation? Given that the wall unit only draws enough power to operate the fan and kick on the water heater, I would think I could use just about any double pole thermostat and not risk overloading it. What worries me is the product description for the Honeywell states "Requires 240 volts - does not work for 120 volt applications" -- does this eliminate me? If the Honeywells won't work, what exactly should I be looking for?

Do I have other options or does the thermostat have to be a double pole line voltage? My electrical/heating knowledge is limited so please correct any misconceptions I may have.

Thanks for any help!
 
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Old 09-09-07, 04:27 PM
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Wink

Well you could put a 220V contactor there then a 24V transformer and any kind of wall tstat you want to use for programmable and how close it holds the temp for you.
 
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Old 09-09-07, 04:42 PM
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You can use the Vision LinePro t-stat, otherwise, we at Home Depot (some store may not have it) has Honeywell Programable line voltage t-stat that will be close it... I don't recall the model off hand.

I may have posted something at one time on here.
 
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Old 09-10-07, 12:37 AM
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Hey guys, thanks for the replies.

First off, a contactor and transformer, I think, are out of my expertise and from a quick search drive the overall price up quite a bit (I have 5 t-stats to replace).

Which Honeywell are you referring to? Are you implying the Honeywell LineVoltPro I mentioned won't work?
 
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Old 09-10-07, 08:55 PM
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Originally Posted by flood1911 View Post
Which Honeywell are you referring to? Are you implying the Honeywell LineVoltPro I mentioned won't work?

It's the Honeywell RLV430A. I forgot to look at the price today. but they are sold at Home Depot.
 
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Old 09-11-07, 12:28 AM
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The RLV430A is single pole, right? If I understand that correctly there's no true "off" and my heating will be kicking on even when it's on the lowest setting, similar to what I experienced when my t-stat was on 50 but not all the way off the heat was still on and my elements were warm to the touch (even when room temp was well above 50).

Or have I got this all wrong?
 
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Old 09-11-07, 01:16 AM
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Wink

When you have a 220V set up like here or say on a AC unit. It will not run are draw power if you kill one leg. Many of the AC units today the contactor only kills one leg of the 220V.
Now if you go into a unit that is that way. You can get bit from the hot leg to ground
 
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Old 09-11-07, 08:07 AM
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Originally Posted by flood1911 View Post

Turbonics, Inc.
Model: 4/5 WM
Series: 32597
115 Volt, 60 Cycle, 1.5 Amps
15 Amp Supply Circuit, unit load less than 2 amps


Wiring: 2 black wires, 2 red wires, one ground (bare) wire

So basically I have double pole thermostats. I know I can use single pole thermostats with double pole wiring by shorting two of the wires,
Thanks for any help!
As you said in an earlier post, you said you can use it, and yes you can use it.. Your fan/heater only use 120v. So the hot wire goes onto the pole, and your nurtural wire are tied together, and ground tried together.

The hot water you have for heating, is this on your own boiler or share boiler in the building with others in the townhouse unit?

Sounds like you said you have this in all your room in the home? My question is if this your own boiler, and paying for gas or is it electric to heat the water, how is the water flow and boiler demand controled?
 
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Old 09-11-07, 09:54 AM
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Originally Posted by Jay11J View Post
As you said in an earlier post, you said you can use it, and yes you can use it.. Your fan/heater only use 120v. So the hot wire goes onto the pole, and your nurtural wire are tied together, and ground tried together.

The hot water you have for heating, is this on your own boiler or share boiler in the building with others in the townhouse unit?

Sounds like you said you have this in all your room in the home? My question is if this your own boiler, and paying for gas or is it electric to heat the water, how is the water flow and boiler demand controled?
The boiler is not shared, I own it. Yes, all rooms (5 total) have this. I have 5 t-stats and all but one operate a single in-wall unit, the other controls two in-wall units. The boiler is heated by gas.

I'm not sure how the water flow and boiler demand are controlled. When testing out the existing thermostats when I push the temp above current (past the soft "click") the boiler kicks on and after about 5 mins the fan in the in-wall unit kicks on. I assume the fan is waiting for the element to reach a certain temp before operating (or maybe just time controlled?).

So if my line is 120V, the 240V t-stat (the LineVoltPro) will NOT work, is that correct?

I appreciate the help...
 
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Old 09-11-07, 06:38 PM
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Originally Posted by flood1911 View Post
I have 5 t-stats and all but one operate a single in-wall unit, the other controls two in-wall units.
So, all of your rooms has this "forced" air heater that uses hot water? No standard radiator??? Was it built like that, or you asked for this set up? Why was this used if you have all "air" heat, and not forced air?

I'm not sure how the water flow and boiler demand are controlled. When testing out the existing thermostats when I push the temp above current (past the soft "click") the boiler kicks on and after about 5 mins the fan in the in-wall unit kicks on. I assume the fan is waiting for the element to reach a certain temp before operating (or maybe just time controlled?).
Have you removed the t-stat from the wall, and only had 3 line voltage wires?

Are you able to take a picture of your boiler, and if there a control, and zone valves, take a pic of that..

So if my line is 120V, the 240V t-stat (the LineVoltPro) will NOT work, is that correct?
I am not sure?? I'll send an e-mail out to a friend at Honeywell, and see what he has to say.
 
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Old 09-12-07, 06:39 AM
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I shot an e-mail out to Honeywell, and he wasn't sure.. he was going to forward the e-mail over to someone who is in the linvoltage controls..

I"ll keep you posted!
 
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Old 09-12-07, 11:26 AM
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Ok, I got a reply back from Honeywell.

They are suggesting the Honeywell's Aube TH140-28-01


I found this on SmartHome web site.
 
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Old 09-17-07, 10:50 AM
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Jay, I really appreciate you looking into this for me. Thanks so much!

I hadn't seen/investigated that t-stat yet but it definitely looks like it solve my issues plus has a nice clean look as well (and price is right on).

Thanks again!!
 
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Old 09-17-07, 05:40 PM
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Glad to help out.

Like I said earlier, post some photo if you can of your boiler set up... Something is driving me nuts on how it's being controled, and it sounds like these line voltage t-stat only controls the heater's fan.
 
 

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