Honeywell MagicStat 28 Programming And Installation Instructions page 7

Replacing a Clock Thermostat that has C
or C1 Clock Terminals?
If you are replacing a Honeywell
®
Chronotherm Thermostat, you may find one
or two wires that go to the C or C1 clock
terminals on the Chronotherm Thermostat
wiring wallplate. Do not allow them to touch,
or you may damage your transformer.
Disconnect the wires and wrap them sepa-
rately, using electrical tape. Do not wrap them
together . Place the wires where they will not
interfere with the operation of the new
thermostat. Record the colors and terminal
designation labels of the remaining wires.
Six or more wires?
If there are six or more wires (excluding
clock wires attached to terminals), you
most likely have a variation of a heat pump
or multistage system. The thermostat is
not compatible with such systems so return
the product to the place of purchase. If you
would like information about which program-
mable thermostats will work with your system,
call Honeywell Customer Assistance at
1-800-468-1502.
Three thermostat wires?
If you have three wires for heating only and
can operate the fan using the fan ON switch,
this thermostat will work with your system.
However, some hot water (zoned) heating
systems have three thermostat wires. The
thermostat will not work without installing an
isolating relay on these systems. For details,
call Honeywell Customer Assistance at 1-800-
468-1502.
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