Hi everyone, first time poster here. I just bought a digital thermostat (Honeywell RTH230B) to replace my old Honeywell thermostat. I'm having some problems figuring out what connections to plug it into. Currently I have 4 wires screwed onto the old thermostat - White, Black, Red and Blue.

The new thermostat has instructions on the wire setup but it doesn't look like my 4 wires will apply in this case. It has Yellow and green mentioned in the manual. This is what it has now:

Rh Rc W Y G

Images is shown here. Am I only suppose to be using two wires then? Red on Rd and White on W? I tested it with that and turned up the temperature. It says the furnace fire should be on (shows the fire icon). I checked the furnace and don't see it coming on.

Thanks.

It should work. Just match up the old wires and colors except:

Connect Rh to Rc and connect to the wire connected to R on the old stat.

Go to the furnace,, open the panel trace the tstat wires to circuit board or what ever they are attached it should be labeled what color wires are attached to what,, look see and let us know

Also tell us what kind of heat you have and if you have A/C. The colors on your old tstat do not follow the usual convention but we need to know more to be sure what we're dealing with.

It must be some really old setup here. I checked downstairs in the basement and took a look at the furnace. I'm not sure where the circuit board is, but I do see some wires connected to a metal piece outside near the pipes (no labels though). I traced the wires and saw it going into some power supply (it shows the voltage and is about 2" x 6" in size). I'm not sure if that's what is needed here. There are two very small wires (white and red) and a couple of thicker black wires connected to it. I also see two large yellow cables connected to that power supply unit.

Any way to trace it back to the old thermostat to see what wires to use? It has all 4 wires connected on the old thermostat (red, white, blue/turquoise and black). My friend has 3 wires at his house I think and he told me to use the white on the Rh connector and blue on the w connector. I removed the pin on Rh and Rc since I'm using 2 wire setup. Should the temperature change be almost instant or in a few minutes? I turned the temperature all the way down to see if the temperature drops in the house.

No A/C for this. I just need it solely for heating the house. So no fans or anything else connected.

Thanks.

This is going to be hard if not impossible without kmowing the brand and model numbers off your furnace so me can maybe figure it out,, do you have any idea how old furnace is? Does it have a standing pilot? Electronic ignitor,, or even is it a electric--gas---or oil furnace,, for us to help you,, you need to help us

I would it's definitely older than 10 years now. OK, I think I found out the brand and model. It's a HydroTherm VGA-175S.

I don't know much about these, but it looks like it's hooked up to the boiler. I see several places on the furnace that mentions boiler also.

The furnace is equipped with an intermittent electric lighter according to the label. It's definitely a gas furnace. Label says Natural gas on it also.

Is there any way for me to trace the old thermostat setup and have it similarly setup on this new digital one? The old one had 4 wires connected by screws. I don't know why. The house doesn't have any A/C or fan system... just heat.

Many thanks again.

Yea, take a picture of the wiring at the furnace area and post a picture using "Go advanced/Manage attachments".

Quote:

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Originally Posted by weaponx8238

It must be some really old setup here. I checked downstairs in the basement and took a look at the furnace. I'm not sure where the circuit board is, but I do see some wires connected to a metal piece outside near the pipes (no labels though). I traced the wires and saw it going into some power supply (it shows the voltage and is about 2" x 6" in size). I'm not sure if that's what is needed here. There are two very small wires (white and red) and a couple of thicker black wires connected to it. I also see two large yellow cables connected to that power supply unit.

Any way to trace it back to the old thermostat to see what wires to use? It has all 4 wires connected on the old thermostat (red, white, blue/turquoise and black). My friend has 3 wires at his house I think and he told me to use the white on the Rh connector and blue on the w connector. I removed the pin on Rh and Rc since I'm using 2 wire setup. Should the temperature change be almost instant or in a few minutes? I turned the temperature all the way down to see if the temperature drops in the house.

No A/C for this. I just need it solely for heating the house. So no fans or anything else connected.

Thanks.

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Sounds like you might have an old "fan center", which is just a transformer mounted to a 4X4 cover plate mounted to a box. Usually have 2 terminals sometimes labeled R and W.

Yes, it's one of those old furnaces that's square like. Will take a picture if still needed... need to find my camera.

I think we got it working. Tested the wires for any currents using voltmeter and found the black and white ones spiked. We used that and it seems like it's working. We tried turning the temperature up and down to see if the furnace will light up at a specified temperature... it did.

The only problem we have now is that the programmable time and temperatures are not working as expected. Like today, I set it to 72 degrees from 6AM to 9AM and then 64 degrees from 11AM to 5PM. I didn't get to check it before 9AM, but as of now it's at 71 degrees when it should be down to 64.

I checked the program presets again and everything looks like it's configured properly.