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View Full Version : BAYSTAT240 to Honeywell TH8320 Conversion


tdmgmm
Dec 13, 2005, 11:01 AM
I am trying to switch my BAYSTAT240 thermostat to a Honeywell vision pro 8000 (TH8320U1008).

My old settings were:

O: Orange
G: Green
Y: Yellow
X2: Connected to white along with W
B: Blue
W: (jumpered to U): White
R: Red
T: Black
F: Vacant


The way I have it hooked up with the TH8320U is:

Orange - O/B
Green to G
Yellow - Y
White - Aux
Blue - C
Red - R (jumper installed to RC)
Black to E
Brown - Vacant

The fan works but I cannot get the heater or a/c to come on. Any suggestions?

labman
Dec 13, 2005, 12:06 PM
Did the instructions say to connect the white to Aux? If not, do they say what terminal the thermostat activates for heat or first stage heat? Go to the heater and see what the white wire is connected to. If it is W, not much help. If it matches any of the labels on the new thermostat, try connecting the white wire to it.

A heat pump needs both a signal to set the reversing valves to heat and a signal to start up. Unusually the white wire provides it. X, O, O/B, and E may be the signal to switch the valves.