new t-stat for comfortmaker M# GUF125A016-N, S# 211502-N43-0073

[jerseykevin]

Hi, here goes, I have a new thermostat I'm trying to install on a Snydergeneral Comfortmaker Mfg. 10/86, model # GUF125A016-n, Serial # 0000211502-0073.  The way it sits now, there is one t-stat for the a/c and one for the furnace. I bought a Honeywell RTH230b programmable T-stat.  I picked Honeywell, well, because the two t-stats now in place are both honeywells and I figured it would translate well.  So off come the old ones, and I got 7 wires. 3 (colors R,W, on the a/c, 4 (Blue, Y,R,W) on the heat. The problem is, the new t-stat has great instructions for up to 5 wire installation.  Since the two red ones are screwed together on the low-voltage board in the furnance, I'm already down to 6. Yay!  Hey, before I roll the dice and just splice two of these bad boys together I figured I'd ask.  So here goes, First of all, tracing the blue and yellow ones from the furnace t-stat downstairs leads me to a low volt transformer (blue - load). The heat t-stat White wire goes through the low volt board to the gas switch, and the a/c white wire goes through same board to the a/c condenser. A/c B goes to same board, to the fan switch.  Both red ones go through same board, leading to the (fan limit pointer???) box on side of unit and back to fan switch. The instructions say Rh to heating power supply, Rc to cooling power supply, W to heating signal, Y to cooling signal, and G to fan.  Somehow I'm just not sure these colors "line up" right here (since I got no Green ha ha), so I put the old T-stats back, and am awaiting further instructions from the GURU. 

[RegUS_PatOff]

 

(forum server problem lost the last few days of messages)

 

since the (2) Red wires are connected at the Furnace, you can connect then at the Thermostat to the Rc and Rh wires with or without the Rc / Rh Jumper wire in the Thermostat.

Cooling White (Compressor) goes to Y (Yellow)

Cooling B (Fan) to G (Green) Fan

Heating White goes to W (White)

Can you explain again where the Heating Yellow & Blue come from ?

Directly to the Furnace Transformer and nowhere else ?

Does one of them also go to the other side of the Fan Limit ?

[applianceman18007260692]

If you could put an el cheapo  timer on the 120 volt side of the  transformer and set it to come on the hours you wish then the furnace would work when you want it and you would not have to worry about wiring expensive programmable stuff that could potentially damage a control board if wired wrong. I was thinking if power was shut down manually to the furnace it will not work right? Why not put it on a simple timer?

[RegUS_PatOff]

He may want to adjust the Thermostat temperature at night by a few degrees.. not turn it off completley at night..

Depending on where he lives... It gets cold here at night in Wisconsin  :brrr: