sburrage
Nov 22, 2008, 03:40 PM
I need help hooking up my new programmable Honeywell thermostat. Because the existing wires to the thermostat were apparently hooked up in a non-conventional fashion-, Honeywell says they cannot help me.The natural gas furnace (not a heat pump) is apparently a NORDYNE Model MGHA-075ABFC-01. The existing Thermostat is an INTERTHERM.
The wires on the old thermostat are connected as:
O-not connected
B-not connected
RH- Blue
W- White
HE – Red
RC- Green
Unlabeled- Yellow (maybe this is supposed to be “C”?)
On the furnace itself, the wires are connected as:
RC – Red
RH- Blue
W- White
G- Green
C- RED WIRE-#2 (#2 wire has only 3 wires) green is not attached to anything, and the white wire is connected to the YELLOW wire of wire 1 with a wire nut. Then the other end of the wire runs under the floor where presumably the other ends of Red #2, and white #2 are attached to the compressor.
I understand when they originally installed this system the Heating guy had a difficult time getting it to work, and he kept changing the wires around and he finally got it to work in after a fashion, but it has never seemed very efficient. So we got a programmable thermostat to try to save some money.
Anyway this seems to be a challenging installation as one of the old thermostat post is unlabeled, and more importantly on the furnace the RC wire is RED, but the GREEN wire is connected to RC on the thermostat. I may need to first hook up the furnace correctly, or else run non standard colors on the thermostat.
Thanks in advance for any help.
The wires on the old thermostat are connected as:
O-not connected
B-not connected
RH- Blue
W- White
HE – Red
RC- Green
Unlabeled- Yellow (maybe this is supposed to be “C”?)
On the furnace itself, the wires are connected as:
RC – Red
RH- Blue
W- White
G- Green
C- RED WIRE-#2 (#2 wire has only 3 wires) green is not attached to anything, and the white wire is connected to the YELLOW wire of wire 1 with a wire nut. Then the other end of the wire runs under the floor where presumably the other ends of Red #2, and white #2 are attached to the compressor.
I understand when they originally installed this system the Heating guy had a difficult time getting it to work, and he kept changing the wires around and he finally got it to work in after a fashion, but it has never seemed very efficient. So we got a programmable thermostat to try to save some money.
Anyway this seems to be a challenging installation as one of the old thermostat post is unlabeled, and more importantly on the furnace the RC wire is RED, but the GREEN wire is connected to RC on the thermostat. I may need to first hook up the furnace correctly, or else run non standard colors on the thermostat.
Thanks in advance for any help.