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View Full Version : Replacing intertherm with honeywell rth7500d


bubs58
Oct 14, 2009, 07:51 PM
I have a nordyne/intertherm thermostat on heat pump hvac system.
Has seven wires: E- emerg heat
W- aux heat
O- RVS Cooling
G- Fan
R- 24 Vac hot
C- 24 VAC Comm
Y- Heat/Cool

The Honeywell has the following designated connection points, C, G, Y, O/B, RC, R, W2, E2, L

Can someone tell me what wires on intertherm corresponds to ones on honeywell?
Thank you,
Dana

hvacservicetech_07
Oct 14, 2009, 09:01 PM
Wire for wire should do the trick. Nothing will connect to the "L" terminal,put a jumper wire between "W2 and E2" and connect whatever is on "W" to those terminals. "O" on the old stat will go to O/B on the new. Good luck!

hvac1000
Oct 14, 2009, 09:03 PM
PS you might have to select either O or B in the thermostat setup.

bubs58
Oct 15, 2009, 07:53 PM
Wire for wire should do the trick. Nothing will connect to the "L" terminal,put a jumper wire between "W2 and E2" and connect whatever is on "W" to those terminals. "O" on the old stat will go to O/B on the new. Good luck!

Thank you for the reply but it doesn't explain what to do with the "E" wire from the intertherm. That's designated emerg heat. Since I would be tying the W wire to both W2 and E2 that doesn't leave me a place for the E:)