Honeywell T874/Q674 Fig. 4Wiring connections., Fig. 5Internal schematic and typical wiring diagram for T874N and Q674C.

60-1147-43
Fig. 4—Wiring connections.
2. Carefully remove and discard the polystyrene packing
insert that protects the mercury switches during shipment.
3. If LED indication (EM.HT., CHECK, etc.) is to be used
with the Q674 Subbase, install the preprinted insert under the
thermostat set point scale (Fig. 8). To install, push both
thermostat set point levers to the far ends of the thermostat. Use
index finger to gently pull out the plastic set point scale about
1/4 in. [6 mm]. Drop insert into recessed area behind set point
scale so that selected LEDs show. Make sure insert is com-
pletely seated in recessed area. Let set point scale pop back, and
set levers to desired positions.
FOR STRAIGHT
INSERTION–
STRIP 5/16 in. [8 mm]
FOR WRAPAROUND–
STRIP 7/16 in. [11 mm]
SUBBASE TERMINAL SCREW
M928
BARRIER
Fig. 5—Internal schematic and typical wiring diagram for T874N and Q674C.
M1860
G
R
W2
X
L1
(HOT)
L2
AUTO
SYSTEM
SWITCH
AUTO
ON
FAN
SWITCH
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS
REQUIRED.
1
CHECK
LED
(GRN)
L
Y
OFF
H1
ANTICIPATOR
RISE
W3
W1
FAN RELAY
DEFROST RELAY
CONTACT
C1
C1
ANTICIPATOR
FALL
H2
HEAT
RELAY 1
COMPRESSOR
CONTACTOR
EM. HT. RELAY
CONTACT
EM. HT. RELAY
CONTACT
OUTDOOR
THERMOSTAT
HEAT
RELAY 2
HEAT
RELAY 3
REVERSING
RELAY
OPTIONAL
COMPRESSOR
FAILURE
DEVICE
CO
H2 ANTICIPATOR
FALL
H1