Please Help - Replacing a Thermostat

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Please Help - Replacing a Thermostat

Post by Grit2112 » Thu Aug 15, 2013 7:10 am

So I can barely turn a screwdriver - but I need to replace a thermostat, and supposedly that is a rather simple DIY task -

Any advice would be greatly appreciated

I am replacing an old RiteTemp 8085c with a Honeywell RTH6530D

Looking at the RiteTemp manual, my current install is for a Heat Pump system with Auxiliary Heat
On the stat I am replacing (RiteTemp), the following wires were -
C (blue)
W2 (white)
RC (red)
O (orange)
RH jumpered to RC
W jumpered to Y
Y (yellow)
G (green)

My options on the new Honeywell - if I try to match are as -
Aux/E (W, W1, W2)
Rc (Jumpered to R)

The honeywell manual says to leave old C unconnected - no problem

My question is about the W, W2 and Y -
I assume my old W2 (white) will go to AUX
What about my old jumpered Y-W setup?
Do I not need to worry about it?
Do I jump the Y and Aux terminal - even though I already have a W2 wire going to AUX? Just a bit confused.

Again - any help would be appreciated. Thanks!

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- Please Help - Replacing a Thermostat

Post by Freon » Sun Aug 18, 2013 10:52 am

I assume this is a battery powered thermostat and that's why Honeywell doesn't need the C (common) connected. However if there is a C terminal on the thermostat check if you can use the C only because then you don't have to worry about low batteries since the power to the thermostat will be coming from the 24 volt feed. If in doubt, don't connect it.

Since you do not have a W terminal, I will assume that a call for heat and cool will both energize the Y terminal thereby powering the outdoor condenser unit. Some older thermostats had separate power on the W when there was a call for heat and on the Y for cooling. Usually that would be for an AC only system, not heat pump. The W to Y jumper made the Ritetemp work on a heat pump

The W2 will go to Aux.

After installation check the thermostat setup program for powering the O/B connection. That connection determines the changeover valve position at the condenser. You can try the system and call for cooling. If you get heat instead, then the O/B setting needs to be changed.

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