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vae_victis 12-31-2011 03:23 PM

Thermostat for electric baseboard wiring help needed
First post so be kind.

I am a little light on the terminology so I'm going to rely mostly on the pictures to tell the story.

I'm trying to replace my old dial thermostat with a UPM HTM611. It controls a 1000W electric baseboard heater:

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Here is the old thermostat:

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Here is the new thermostat:

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Maybe I'm missing something but it seems like it should be compatible, no?

Here's the wall box:

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There's 3 red wires, 3 black wires (bound together with a wire nut), and what looks like 3 ground wires way at the back (bound together with a wire nut).

Here's what the old thermostat looked like when it was hooked up:

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The old thermostat had a red wire and a black wire coming out of it. One of the red wires from the wall (call it red1) was tied to the red wire out of the thermostat and the other two red wires (red2 and red3) from the wall were tied together and tied to the black wire from the thermostat. (in the picture the two red wires look like white wires but they're just coated with drywall dust)

The new thermostat just has 2 black wires coming out of it. So I simply tied one of them to red1 and one to the tied together red2 & red3. Seemed to work at first. It turned on fine and I was able to adjust the desired temperature. But as soon as the desired temperature went above the ambient temperature the baseboard would kick on but after a couple seconds the thermostat would shut off.

I tried hooking the thermostat to different combinations of red wires (unbinding red2 & red3) but the combination of red1 and red2 was the only one that would turn on the thermostat. And I would get the same result with the thermostat shutting off when the baseboard kicked on.

So far I've left all the black wires alone. Before I start messing with those I figured I'd come here for some advice first. Any thoughts? Do I just plain have the wrong type of thermostat? TIA

Tator1076 12-31-2011 04:11 PM

Take a pic of new t-stat were the wire go to

Tator1076 12-31-2011 04:13 PM

I'm thinking you just get by put all black together and were red comes from breaker tie it one side of stat and were other red wire goes to heater put that on other wire. That should be it

vae_victis 12-31-2011 10:20 PM


Originally Posted by Tator1076 (Post 808479)
Take a pic of new t-stat were the wire go to

Like this?

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vae_victis 12-31-2011 10:32 PM


Originally Posted by Tator1076 (Post 808481)
I'm thinking you just get by put all black together and were red comes from breaker tie it one side of stat and were other red wire goes to heater put that on other wire. That should be it

I can't tell one red wire from the other. They all look exactly the same and come from the same place.

I think I've already done what you described though. I tried hooking the two wires from the thermostat to every combination of the 3 red wires and only one combination turns on the unit (the ones I've labeled 1 and 2). Problem is when I increase the desired temperature over the ambient temperature, thereby activating the baseboard (which does turn on), the thermostat turns off (shorted out? overpowered?).

vae_victis 01-02-2012 12:01 AM

Also now I notice two of the five baseboards in my house no longer have power. The one I'm working on plus two others continue to have power but two other ones I didn't touch now don't (assume they lost it when I turned off the breaker and never regained it when I turned it back on). I've turned all the breakers back on and even flipped all the ones I shut off before I found the one for the baseboards.

So here I am with all breakers on, all wires and connections as they were, untouched from a couple days ago on those two baseboards now with no power. Everything else in the house continues to have power.

Is there something else I have to flip to get these baseboards powered again after shutting off the breaker? Would be weird if there was, since I didn't do anything to the other three still working baseboards and all five seem to be of the same age/appearance/manufacturer.

One of the non-working baseboards has an integrated thermostat and one is controlled by a wall thermostat.

Another bit of info which might be useful to a reader: from what I can tell, the way the wall thermostats are currently wired there are only two settings, on and off. Despite the fact that the thermostat has a dial with numbers on it, the baseboard seems to turn on when you turn the dial past the same point (no matter what the ambient temperature) - say 15 degrees - and doesn't turn off until you turn the dial back below 15, again regardless of the ambient temperature.

I feel like I should be involving the black wires somehow to get it working right. But what do I know.

Anyway, if anybody has any further insight on my original issue or my new problem, I would really appreciate it.

Houston204 01-02-2012 01:25 AM


December 14, 2010

UPM Marketing Recalls Line Voltage Thermostats
The Electrical Safety Authority is notifying the public that UPM Marketing Inc. has announced a voluntary recall and product upgrade replacement of the following products. Affected devices are to be replaced immediately.


The unit may overheat and emit smoke, especially when the load has exceeded the specified maximum rating.

Description/Models: UPM models: HTM611A and HTM621, Noma models: HTM611A (52-2544-0) and HTM621 (52-2545-8). Affected units were manufactured in 2008 and has serial number starting with "08". Units with serial number not starting with "08" are not affected.

beenthere 01-02-2012 04:26 AM

Nice catch Houston.

biggles 01-02-2012 06:31 AM

what ever 2 wires you disconnected from the old stat are the closures..nut them together and put the CBs back on see if it all runs all your doing is breaking one side of the 230V which shuts the baseboard down.if that od stat was running more then one lenght of baseboard be careful...don't worry about what is connected together within the box just the 2 wires you disconnected from the breaker into the box 230V should be RED and Black readable with a meter...going to the stat can be any combo your only breaking one side of that 230V...either red or black to ground or neutral should read 115V

Houston204 01-02-2012 10:20 AM

Thanks. I googled the stat model number and added pdf and that recall information came up.

vae_victis 01-05-2012 10:53 AM

Thanks for the help. I took back the recalled unit and bought a new one (actually a year older, 2007) and it works fine. And for whatever reason, once I had hooked up that thermostat, power returned to the two "powerless" thermostats. Don't ask me why, but I guess it stands to reason if the problem was caused without action, so would be the solution. :)

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