Replace Heat Pump Thermostat

Problems related to residential installations.

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Replace Heat Pump Thermostat

Post by ayabtu123 » Sat Jan 22, 2011 12:27 pm

I am trying to replace my outdated Baystat 239a thermostat with a Honeywell RTH6350D. I have a Trane XR14 heat pump. I have done quite a bit of research, and have came to the following conclusions but I am not 100% confident with what I have determined. I have pieced together this game plan using the manual and some other posts I thought were relevant. Has anyone had any experience with this type of system? I am specifically concerned about the B (common?) wire not being used on the new thermostat. Any insight would be greatly appreciated. Thanks.

Baystat 239a Setup

Y - Yellow
R - Red
T - Tan
W - White
G - Green
O - Orange
X2 - Black
B - Blue
U - not used
F - not used

Honeywell RTH6350 Conversion (Old thermostat terminal in parenthesis)

L - Not Used
E - Black (X2)
Aux - White (W)
G - Green (G)
O/B - Orange (O)
Y - Yellow (Y)
R - Red (R)
Rc - Jumper to R

Old thermostat T and B wires taped off and not used.

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- Replace Heat Pump Thermostat

Post by nomadpeo » Mon Jan 24, 2011 12:07 am

'b' may be an aux common. maybe 't' was used to power a light on the old thermostat. your new connections look right.

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