Connecting TH8321U thermostats to older packaged heat pumps

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  #1  
Old 11-18-15, 02:52 PM
J
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Connecting TH8321U thermostats to older packaged heat pumps

I think by reading existing threads I have the information I need to do the work I want to do. However someone out there may know of a pit fall that could save me time and money (and maybe a burned out unit).

I have 2 Honeywell TH8321U1097 and 1 TH8321U1006 I would like to use with 3 heat pumps my family has installed. The heat pumps are all 1 cool stage / 2 heat stage (the 2nd stage being aux heat strips). All units are packaged Trane systems. I have already reconfigured and set up the schedules for the Honeywell thermostats.

The day I went to swap out the old analog thermostats I quickly learned there have been some changes in labeling over time. Below are the 3 systems with equipment model numbers and existing wire connections (yes, I know one has blue / black wires reversed, and deserves my scrutiny before continuing). Any feed back, obvious or obscure mistakes, helpful hints, warnings, or questions I need to answer would be most appreciated.

The third analog thermostat has an "AUTO" system selection, the other two must be manually switched between heat and cool.

[table="width: 500"]
[tr]
[td]WCM030F100BB[/td]
[td] [/td]
[td]WCC024F100BF[/td]
[td] [/td]
[td]WCC048F100BE[/td]
[td] [/td]
[/tr]
[tr]
[td]BAYSTAT 239[/td]
[td] [/td]
[td]BAYSTAT 239A[/td]
[td] [/td]
[td]BAY28X138[/td]
[td] [/td]
[/tr]
[tr]
[td]X2[/td]
[td]black[/td]
[td]X2[/td]
[td]black[/td]
[td]X2[/td]
[td]blue[/td]
[/tr]
[tr]
[td]O[/td]
[td]orange[/td]
[td]O[/td]
[td]orange[/td]
[td]O[/td]
[td]orange[/td]
[/tr]
[tr]
[td]G[/td]
[td]green[/td]
[td]G[/td]
[td]green[/td]
[td]G[/td]
[td]green[/td]
[/tr]
[tr]
[td]Y[/td]
[td]yellow[/td]
[td]Y[/td]
[td]yellow[/td]
[td]Y[/td]
[td]yellow[/td]
[/tr]
[tr]
[td]T[/td]
[td]brown[/td]
[td]T[/td]
[td]brown[/td]
[td]T[/td]
[td]brown[/td]
[/tr]
[tr]
[td]R[/td]
[td]red[/td]
[td]R[/td]
[td]red[/td]
[td]R[/td]
[td]red[/td]
[/tr]
[tr]
[td]W[/td]
[td]white[/td]
[td]W[/td]
[td]white[/td]
[td]W[/td]
[td]white[/td]
[/tr]
[tr]
[td]U[/td]
[td]open[/td]
[td]U[/td]
[td]open[/td]
[td]U[/td]
[td]jumper to W[/td]
[/tr]
[tr]
[td]F[/td]
[td]open[/td]
[td]F[/td]
[td]open[/td]
[td]F[/td]
[td]open[/td]
[/tr]
[tr]
[td]B[/td]
[td]open[/td]
[td]B[/td]
[td]blue[/td]
[td]B[/td]
[td]black[/td]
[/tr]
[/table]

From an earlier thread I found the following terminal conversions (old to new)

F = L
O = O/B
Y = Y1
X2 = E
W = Aux
G = G
T = Tape off this wire
B = C
R = Rc and R

Thanks in advance,
Jim T
 
  #2  
Old 11-20-15, 10:45 AM
Houston204's Avatar
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Remove power to the units before replacement or you can pop a fuse or burn up the transformer by touching R to B (C).

You must also configure for heat pump with Aux heat.
Set function 170 to 7.

Verify that function 190 is set to 0.
(The O/B terminal is O)
 
 

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