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marriedmanw 02-28-2010 03:18 PM

Multi stage heat pump thermostat
Hey, I changed out my thermostat on a multi-stage heat pump and it's working fine in heat and E heat mode, but I have question about the 1st and 2nd stage heat. I have not tried the AC mode, but I believe that is on the reversing value (O) and should be fine. My question is: Is Y1 the 1st stage heating and W2 is the 2nd stage heating then Emergency heat is pulled from the 2nd stage with the compressor locked out?
Below is how I have connected my thermostat, but while connecting it I kept thinking the Emergency was 2nd stage.

Thanks in advance. :thumbup:

Old Thermo: Honeywell CT70(Mercury)
X- Blue
W2 - White
R- Red
G - Green
O - Orange
Y1 - Yellow

New Thermo: Honeywell RTH3100C
C - Blue (Common)
R - Red (Return)
O - Orange (Reverse Valve)
G - Green (Fan)
Y1 - Yellow (1st stage heat?????)
W2 - White (2nd stage heat????)
Emergency - W2 to E connected by Jumper

Houston204 02-28-2010 03:41 PM

Yes, you are correct.

marriedmanw 02-28-2010 04:12 PM


Originally Posted by Houston204 (Post 407420)
Yes, you are correct.

Thank you for the quick reply. I was over analyzing the problem and got myself turned around. The previous HO didn't have the E heat jumpered and the old t-stat had built-in jumper on Y1 and W1. Until I started asking on this thread and remembered O is reverse valve, I was thinking cooling mode ran on Y1.

Thanks again. :thumbsup:

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