CT50A, CT51A, CT53A THERMOSTATS
69-0265ES
2
!
Using a pencil point, move the heat anticipator pointer
to the number it was set to on the old thermostat. If you
could not find the anticipator setting on the old
thermostat, use the setting for your type of system
shown in the table below.
NOTES: If the furnace stays on beyond the thermostat set
temperature, move the anticipator pointer down
by 0.1 ampere.
If the furnace shuts off before the set tempera-
ture is reached, move the anticipator pointer up
by 0.1 ampere.
Never adjust the anticipator below 0.3 ampere.
!
Loosen screws holding thermostat to the wall and
lift away.
!
Disconnect wires from old thermostat or subbase. If
your thermostat has more than 2 wires, as you
disconnect each wire, tape the end and label it with the
letter of the terminal designation to make reconnection
to new thermostat easier. Take care that these wires
do not fall back into the wall opening.
!
Retain the old thermostat for reference purposes until
your new thermostat is functioning smoothly.
WIRE AND MOUNT
NEW THERMOSTAT
For CT50A
!
Connect one of the 2 wires from the wall to each of the
two terminals on the back of the thermostat. Tighten
the screws.
For CT51A
!
Connect 4 wires from the wall to matching terminals on
back of thermostat. Tighten the screws.
!
If using CT51A for ELECTRIC heat systems, you must
install a jumper between thermostat terminals 1 and 2.
CT53A
!
Connect wires to R and W for 750 mV systems.
Connect to R and Y for 250 or 500 mV systems.
Tighten the screws.
!
Grasp the thermostat cover at the top and bottom with
one hand. Pull outward on the top edge of the
thermostat cover until it snaps free of the thermostat
base.
!
Carefully remove and discard the red plastic pin
located above the mercury switch. This pin protects
this switch during shipment.
!
Fasten thermostat to the wall with one of the screws
supplied, using the top mounting hole.
!
Place your level across the top of the thermostat and
level it. Start the second screw, supplied, in the center
of the bottom mounting hole.
!
Recheck for level positioning, then firmly tighten both
mounting screws.
Table 1. Heat Anticipator Settings.
Your heating system
Heat anticipator setting
Steam
1.2
Hot water heat
0.8
High-efficiency warm air
0.8
Standard warm air
0.4
Electric heat
0.3
M3775
TERMINAL
SCREWS
(CT51A SHOWN)
M11902
