Hey,

Old honey well thermostat is set up as follows.

R- Red
RH- black
W- White
Y- black
G- Green

New thermostat terminals are as follows

R
RC
W
Y
G

Help which wire do I wire into the RC the old R or the old RH... when I tried the RH it didn't work and it is an old furnace so tracing the wires back was useless couldn't see where they go.

Thanks

Just adding on as per 1000's advice

Furnace is GAS- has a water source Heat pump next to the furnace.

Can't say the name of the furnace as it is old and couldn't find model numbers

The high limit fan control is buggered and requires replacement have to keep fan running all the time

New tstat is the Pro 6000 honeywell old one is mercury round stat model number unable to read.

Hope that helps

Do you have a/c? The red and white are for heat the y for a/c if it is heat try red to rh white to w you can put g on green there may be a jumper between rc and rh check this

Figured it out here is the answer if anyone else comes across it...

Old honey well thermostat is set up as follows.

R- Red
RH- black
W- White
Y- black
G- Green

New thermostat terminals are as follows and you attach the old wires as such

R to old RH (heating 24v)
RC--- to old R (cooling 24v)
W--- to W (heating )
Y --- to Black (cooling)
G --- G (FAN)


Thanks all!