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wladmin99 07-30-2011 11:45 PM

Have I steamed my thermostat to death!!
Help!! I think i have Blown out my Thermostat, while trying to steam off wall-paper nearby. I didn't think about avoiding the area.....

It controls our Heatpump, electric furnace and humidifier.....

It started flashing number eventually went blank..... There is no obvious On/Off or Reset switch. I tried hitting various one point, it flashed on, saw code PF (Program Function mode ??). one point the heat pump actually went back on, felt cool air running, so it seemed to have reset itself.... then system shut off again... Tried pressing varius buttons on thermostat, and it really seems dead now.... I have tried re-setting the breakers on my electric panel as well as on the furnace/blower unit ....

The Thermostat is a simple one (non-programmable), but it is branded to the name of the company that installed it.... There is no manufacturer name on the front of the thermostat cover, nor on the back of the cover, when I take it off..... and needless to say I have no manual.

Any ideas for a way to reset the thermostat? it is a very simple display...shows 2 digital numbers..... Everything else is just LED indicator lights.

( ) ( ) ( ). + -
Mode Fan View. Up Dn (arrows)

Note: A few hours later, the thermostat display lit up again ..... All by itself, and displayed PF again.... We tried the up arrow.... And it looked totally normal....
Showed current room temperature, was able to see the Set temperature... LED indicator light showed it was in cool mode .... And cold air came out of the vents!! But the thermostat display went blank/dark again after a total of two minutes.

So have I basically killed it and it needs replacing, or is there a way to reset it???

HVACDave 07-30-2011 11:57 PM

Probably has a couple of "AA" batteries in the back, look for a small screw on the bottom to release front cover, or it may just snap onto a faceplate, try replacing batteries first, check to make sure it is all dry inside while you have cover off, make sure screw connections are tight. Good way to start out and let us know how you make out from there.

wladmin99 07-31-2011 08:38 AM

Sorry, No batteries... It is not a fancy, battery backup with LCD display model.

Circuit board is attached to the front cover.

Label on circuit board:
ET115-02 R0
900-1058 512545-044
7/01 Made in Canada

Oh yeah, we are in Montreal, Qc Canada

...and we got the following reply from FixYa:

Ok here is the way you need to wire the new thermostst once you get it. and in the mean time Use the wiring color code I gave you and check it against your furnace and thermostat. If everything is ok there, Remove the wiring from the thermostat. This is going to sound scary but don't let it intimidate you. Take the red wire and connect it with the green wire, the furnace blower should come on. Seperate them and within 1 1/2 minutes the blower should shut off. If all that functions connect the green red and yellow together, there will be a little spark, its ok. Then seperate them and make sure everything shuts down. If that happens, you have a thermostat that is not working properly. You can connect the green, red and yellow to make the ac unit run but it won't shut off till the wires are seperated. There is no way for me to know what thermostst you have since there is over 100 of them in the market. These usually never have any resets on them. You can try removing the batteries if it has any and let it set for 1/2 hour and then put new batteries is and see if it resets itself. If you need a new thermostat they can be purchased at any hardware store. Here is the wiring code.
RC= 24 volts hot A/C, usually red wire
RH= 24 volts hot Heat Mode, jumper to RC
G= Fan or blower, usually green wire
Y= A/C contactor, usually yellow wire
W= Heat, usually white
C= Common 24 volts neutral. MUST GO TO FURNACE COMMON. ,usually blue.

wladmin99 07-31-2011 08:52 AM

For what it's worth I am in Canada. I am not sure if wiring code is much different.

After taking off the front cover, I see 3 wires:
These come out of the wall, and go into 3 terminals on the back of the unit.

I took a deep breath, and unscrewed the back off the wall.
I see blue and yellow wires which are wired together, and there is a lonely green wire which is not even stripped, simply wrapped around the main wire housing, not connected to anything.

How to proceed?

HVACDave 07-31-2011 09:02 AM

Any letters on the points where the wires tie onto the old stat R,W,Y,G ? The wiring codes are the same in Canada

yuri 07-31-2011 09:31 AM

Post a pic of it. Post the brand name and model of the furnace and heatpump. Usually you need 4 wires or more to run a heat pump.

REP 07-31-2011 05:16 PM

When you go to the store to buy another thermostat,get a decent Honeywell or White Rogers stat.Forget about those other stats no matter what it says on the front cover. A couple of times in my career I was talked into installing other brands and it was always more trouble than its worth.
Those two companies have been making stats for more than 75 years,they are not johnny come lately like the others.

wladmin99 07-31-2011 06:24 PM

On the base of the stat, there are simply 3 terminals, labelled very helpfully: 1,2,3 which had wires going in Black, White, and Red respectively.

Behind the back of the stat, the Blue and the Yellow were twisted together.

The green is NOT in use.

At this point, i am NOT trying to salvage the stat, I simply want to connect a couple wires so I can get the heat pump and the fan/blower on furnace is really hot here....

I will either get a svc call or attempt installing my own stat, but they don't take calls until tomorrow.

I have tried touching the following wires together, to see if it would get something going:

I left the blue and yellow wired together, then tried:

Black and Red together had no effect.
Black and Red nothing
White and Red nothing


wladmin99 07-31-2011 06:35 PM

I have got a multimeter, which I know and black leads....

What wires should I try touching to see if I can provide any additional helpful information.

yuri 07-31-2011 07:13 PM

none. you may be shorting out the circuit board in the furnace and causing more damage.:whistling2:

wladmin99 07-31-2011 09:56 PM

One of the other replies, had me trying to touch different leads together ..

Nothing worked....Gave up in frustration.....

Put it all back together ... And of course it works now!

Do you think it just needed over day just to dry.....

All's well that ends well!!

Thks to all who read this thread and tried to help!!


wladmin99 08-01-2011 02:12 AM seems to run for a good long while, and then the whole thermostat panel goes dead and system goes off.:censored:

Eventually starts up again....:wink:

Will wait and see.....

Temperature in house is coming down!

beenthere 08-01-2011 04:20 AM

Just get a new thermostat before this one dies in the middle of a heat wave.

wladmin99 07-21-2012 12:00 AM

Yeah:thumbup:, Svc tech eventually came and installed a new one ....

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