The chances that any body reading on this goup has the exact
two thermostat models you are asking about in hand approaches
zero as an upper limit.

Assuming that the presently installed Trane worked correctly at some time,
get out your Trane manual for the Trane unit and find out from
the manual what the *function* of each of the terminals on the Trane
unit is or was. Write those down, e.g. Terminal 1 Blue = heat on,
Terminal 3 Yellow = AC on, etc.

Then look in the manual for your new Honeywell and find out what
functions go with what terminals in the Honeywell. Write those down.
Then match up the functions with the correct color wires.

Consider labeling each wire for its function befre disconnecing
the Trane, and keep those labels on each wire after connecting up
the Honeywell.

If you don't have a manual for Trane, google for their web site, find
a manual, download and print it out.



dancensound wrote:
I am tring to replace a Trane BAYSENS008B thermostat That has 5 wires as
follows Terminal #1 BLUE,Terminal#2 RED,Terminal#3 YELLOW, Terminal#4
Green, Terminal#5 White,with a HONEWELL RTH7500 on what terminals do place
my existing wires on the new thermostat?