60-1147-45
Fig. 7—Internal schematic and typical wiring diagram for T874R and Q674L.
L1
HOT
L2
1
X2
W2
EM. HEAT
LED (RED)
AUX. HEAT
LED (GREEN)
HIGH LIMIT
SWITCH
FAN RELAY
G
EM. HEAT
RELAY
COMPRESSOR
CONTACTOR
Y
E
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
H1/C1
ANTICIPATOR
H1
H2
H2
ANTICIPATOR
1POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M3685
FALL
R
FALL
L
C1
HEAT
RELAY 1
HEAT
CONTACTOR 3
EM.HT. RELAY
CONTACT
OUTDOOR
THERMOSTAT HEAT
CONTACTOR 2
AUTO
ON
FAN SWITCH
O
X1
B
W3
OPTIONAL COMP
FAILURE DEVICE
DEFROST
RELAY
DEFROST
RELAY
REVERSING
VALVE
EM.HT. RELAY
CONTACT
COOL RELAY
HIGH
PRESSURE
SWITCH
LOW
AMBIENT
CUTOFF
4. Turn over thermostat base and note the spring fingersthat engage the subbase contacts. Make sure the springfingers are not bent flat. Flat fingers prevent proper electricalcontact with the subbase.5. Set the second stage heat anticipation indicator tomatch the current rating of the controlled equipment. SeeHeat Anticipator Setting section. The first stage heat antici-pator and the cooling anticipator are nonadjustable.6. Note the two tabs on the top inside edge of thethermostat base. The tabs fit into corresponding slots on topof the subbase. Mount the thermostat on the subbase.7. Align the two captive mounting screws in the thermo-stat base with the posts on the subbase (Fig. 9). Tighten bothscrews. Do not overtighten screws because damage tosubbase posts can result.Fig. 8—LED space location and adjustable lever
stops.
TIGHTENING SCREW
ADJUSTABLE STOPS
LED SPACE
M7557