[GregN]

I've searched all the earlier Q&A and can't seem to find a matching problem. I am trying to replace an older 2 wire thermostat with a fancy, new wireless programmable thermostat. I am only running heat. I just want on/off and that's it.

The furnace is a Burnham Series 2 Gas Boiler dated 10/2000

The Wiring Block at the furnace is arranged in this way

R C
W G Y

The old round thermostat (Mechanical Type) had 2 uncolored wires attached to G and R. I assume that when the thermostat activates these are simply shorted. The W in the above setup is unused. The instructions for the new thermostat indicate W as "call to heat".

We have a remote receiver with some new wire that can be installed down by the furnace but the furnace immediately shuts down or makes nasty transformer? Noises given the various wiring configurations we have attempted.

I apologize if I haven't provided sufficient information above but any thoughts would be appreciated. Is it possible that I just can't use anything but a 2 wire type thermostat?

[tkrussell]

Can you provide the make and model number of the thermostat you want to use?

Also give more info on the heating system. It is a boiler, but is it pumped water with circulator pumps, zone valves, forced air with heat exchanger, etc?

What kind of furnace controller is there?

[GregN]

Thank you for your quick reply.

The thermostat is Totaline P474-1100RF with the receiver being 1100REC

There is a circulator pump, a Bell & Gossett - I don't believe the house has zones. It is either on or off and pumps water to any radiators in the system. (The old big metal kind)

I don't really understand what a furnace controller is or where to find a tag. There was nothing obvious visible. I don't know if it's a bother or a help but I took a bunch of pictures and posted them at

http://stonehenge.ranchoweb.com/images/furnace/

Thank you,
Greg

[labman]

Most heating plants and thermostats use a red Wire from R to R, and for heat use a white wire W to W. Sounds more like your boiler is wired to have the G terminal activate the heat. All most thermostats do is switch red from the transformer on and off to the W which activates the gas valve or whatever needed for heat. If the old thermostat gave you heat by switching the R terminal to the G terminal, the new one should by connecting the R to R and W on the receiver to G on the boiler.

[GregN]

I think we tried that and got an aborted start. The furnace relay? Clicked - the damper opened and then closed but the furnace wouldn't fire. Either that or it was the time we got some scary noises coming like jammed electrical stuff going on. My brother seemed to think that it was the common that was throwing things off. The original thermostat didn't have a common just the 2 wire R-G connection. Do think it's worth considering that they may have placed the common to a different connection than C? Is there a way to test for that?

I will try the W to G connection again and see what that does and if it's OK I'll report back.

Thanks,
Greg

[labman]

The old thermostat was nothing except a switch. When the room got cold, the tube tilted and the mercury ran to the end with the contacts, connecting them. The new thermostat is more complicated, but still connects the R terminal to the W when the temperature is below the set point. Unless something else was changed, no reason it wouldn't work connecting the old wires to the R and W of the receiver. The receiver may need the wires from the transformer connected to R and B or C. If the boiler is wired properly, the R and C contacts should connect directly to the transformer and have 24 volts AC across them. With nothing else connected, try jumpering the 2 contacts the old wires were connected to. If it doesn't work right, something else is wrong.

[hvac1000]

Looks like a stamp collection to me. LOL

[GregN]

When I connect W to G and R to R I get a loud buzzing sound like an electrical jam or something. I tried this with and without the C connected thinking if it had no power - there wouldn't be a problem. (There was) I also tried reversing the W to R and R to G in case it was a polarity problem but still the buzz. Hopefully I haven't destroyed this $100+ receiver.

Thanks again for your help and any advice you can offer.

[GregN]

I just re-read your early post and I have 27 volts between R and every single other post except W which seems to be connected to nothing. I am wondering if I should jumper power to W and then hook into that with the receiver!! I'm muddled.

[GregN]

Still re-reading earlier. Sorry. Yes, the last time I tried it a direct short worked just fine. It's the only thing that runs the darn furnace.

Thanks again.

[GregN]

I went back and started over again. R to R and W to G and C to C and everything worked great. Thank you for patience and assistance. I hope this post will be of some service to others.

Thank you,
Greg

[labman]

Many years ago when I was managing a factory, a vendor gave me a fact sheet. One item was that there can be such an inrush of air on opening a cabinet that wires are blown from one terminal to another. Sounds like the wires that were originally connected to the W terminal of your furnace were blown over to the G terminal.

The weather took a turn for the nasty here, 25 degrees and maybe 3'' of snow by morning.

[anon098]

I have the same set-up. The problem is providing the wireless receiver with power. That's why the furnace won't fire. I have the Venstar 1100rec but I believe it is the same deal. Venstar sells a two-wire kit which has an additional 24v transformer. It can be plugged directly into an AC outlet to provide the power for the units additional signal reception capabilities. I found this thread because I am looking for a wiring schematic to bypass buying this additional equipment and drawing the power from the transformer already installed on the boiler. I also have a Burnam series 2. Any help would be appreaciated though I realize this thread is many years old now.