d2481290
May 28, 2009, 04:53 PM
Hello everybody,
I've been trying to replace an entry-level Honeywell thermostat - TH3100D - with a programmable model - RTH8500 - from the same company.
The TH3100D had five wires connected:
WYGORc[shunted with R via jumper] B and C were not used.
However, for the RTH8500, W and O use the same connection; according to their manual, there should be no O wire, unless you have a heat-pump (I don't - I have an gas-burning boiler and a York air-conditioner outside). The "typical" and "alternate" wiring schemes described in their manual show some other wiring (C, Y, etc) which I don't have.
The "typical" scheme (with O left out) works fine for heating - but the air conditioning doesn't pair up with the fan: the device itself starts functioning, but its effect is nil, because the fan won't kick in.
The "heat-pumps only" scheme, which makes O go into W's place and W into Aux (shunted with E via jumper) sets the fan ON permanently (with no possibility of stopping it), but doesn't start the air conditioning system.
What's the catch here? What am I doing wrong? Where should the O wire go?
I've been trying to replace an entry-level Honeywell thermostat - TH3100D - with a programmable model - RTH8500 - from the same company.
The TH3100D had five wires connected:
WYGORc[shunted with R via jumper] B and C were not used.
However, for the RTH8500, W and O use the same connection; according to their manual, there should be no O wire, unless you have a heat-pump (I don't - I have an gas-burning boiler and a York air-conditioner outside). The "typical" and "alternate" wiring schemes described in their manual show some other wiring (C, Y, etc) which I don't have.
The "typical" scheme (with O left out) works fine for heating - but the air conditioning doesn't pair up with the fan: the device itself starts functioning, but its effect is nil, because the fan won't kick in.
The "heat-pumps only" scheme, which makes O go into W's place and W into Aux (shunted with E via jumper) sets the fan ON permanently (with no possibility of stopping it), but doesn't start the air conditioning system.
What's the catch here? What am I doing wrong? Where should the O wire go?