[biggsgolf]

I am replacing a Robertshaw 9520 TSTAT with a Carrier TSTATCCREC01. The current wiring on 9520 goes to these terminals. W2 has only a jumper.
R,
Y1,
O,
G,
E,
C,
And a jumper from W2 to E.

The carrier terminals are as follows:
C,
G,
Y1,
O,
W1,
R,
Y2,
W2.

They show the following wiring for a six wire, 1 stage cooling, and 2 stage heating heatpump:
Old wiring designation first:
R to R,
Y1 to Y1,
O to O,
G to G,
W2 to W2,
C to C.
I am confused since 9520 currently has no wire to the W2 except the jumper from E. Would I hook up according to these directions and hook the old E black wire to W2, and not install a jumper? Help is appreciated! Bruce

[labman]

Neither anybody else here or I seem to have the info you need. You may have to do some more digging yourself. Whoever sold you the thermostat should be willing to answer a few questions too. Did it come with much in directions? Does your system expect the thermostat to choose a heating rate? Are the E and W2 for different heating rates? Unless either your heating unit or the new thermostat are set up to choose different heating rates, I would jumper both heating rates to the terminal on the thermostat that signals for heat. Also, where is the control for the supplementary heat, air handler, thermostat, or manual?

The new thermostat has all the same terminals as the old except for W1 and Y2. My guess is that the Y2 is for a second A/C rate, and you should leave it unconnected. It sounds like W1 replaces E for one heating rate. Unless the new thermostat gives directions for controlling the heating rate, I would jumper W1 and W2, and connect the wire that went to E to one of them. Even if the thermostat and heating system are both set up to have the thermostat select different heating rates, you would need a 7'th wire for the thermostat to control it.

[labman]

I didn't find your email until today. Looking at the single stage cooling 2 stage heat pump, if that is what you have, I assume you already have it all connected up if your system has the terminals listed. If you still need help, let me know. Posting here is better than email. Not only will I find it faster, but others drop in sometimes with good ideas.

My Yahoo account fills up with spam and messages from All Experts, and sometimes I don't find things until I work at cleaning out my inbox.

Those were useful links you posted. I can use them to be more helpful in areas where I have less experience.

http://www.icca.invensys.com/manuals...w/110-733c.pdf

http://www.thermostatusa.com/pdf/CCR...stallation.pdf
G or F Fan G
Y1, Y or C Cooling Y1
W1,O,B
W1, W or H Heating
Rh, R, M, Vr, A Power R
C Common C*
W1,O,B**
O/B Rev. Valve
2nd Stage Cool
Y2 Y2
2nd Stage Heat
W2 W2
RS+5 Remote Sensor +5vdc
RS Remote Sensor Signal
RS G Remote Sensor Ground
CK1 Dry Contact Switch
CK2 Dry Contact
* C may not be used on all systems.
** O/B is used if your system is a Heat Pump.