INSTALLATION INSTRUCTIONS
69-0265ES
CT50A, CT51A, CT53A
Thermostats
CT51A
CT50A Heating only
Compatible with most 2 wire gas and oil heating systems.
CT51A Heating/Cooling
Compatible with most 4 wire gas and oil heating systems
and electric heat. Will not work on Heat Pump systems.
CT53A Millivolt heating only
For 250, 500, 750 millivolt systems.
PREPARATION FOR INSTALLATION
Assemble tools required; screwdriver, level, wire stripper.
REMOVING OLD THERMOSTAT
!
Begin by turning off power to the heating system at
the main fuse panel. Most residential systems have a
separate switch box or circuit breaker for
disconnecting power to the furnace.
!
Remove cover of old thermostat. Cover normally
snaps off when pulled firmly from the bottom. If it
resists, check for a screw that locks the cover on.
MERCURY NOTICE
If this product is replacing a control that contains
mercury in a sealed tube, do not place the old
control in the trash. Contact your local waste
management authority for instructions regarding
recycling and proper disposal.
For CT50A, CT51A Installation
!
Before removing the old thermostat from the wall, look
at it carefully to locate the heat anticipator adjustment
mechanism. See illustration below to help you
recognize the heat anticipator. Make a note
here _____ of the anticipator setting.
IMPORTANT
Setting the heat anticipator allows the thermo-
stat to maintain accurate temperature control.
MOUNTING CLIPS
(FOR COVER)
MOUNTING CLIPS
(FOR COVER)
TOP MOUNTING
HOLE
ADJUSTABLE HEAT
ANTICIPATOR
SETTING LEVER
(CT50A, CT51A ONLY)
FAN SWITCH
(CT51A ONLY)
SYSTEM SWITCH
(CT51A ONLY)
BOTTOM
MOUNTING HOLE
TEMPERATURE
SETTING LEVER
M11901
