Honeywell CHRONOTHERM T8624C User Manual page 9

Fig. 8—T8624D 2-stage heat/2-stage cool thermostat with HEAT-OFF-COOL system and AUTO-ON fan
switching; auto fan on heat and cool; convertible to auto fan on cool only.
THERMOSTAT
LOGIC CIRCUIT
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
FOR GAS OR OIL APPLICATIONS OR ELECTRIC HEAT APPLICATIONS
2
WHERE THE FAN OPERATION IS CONTROLLED INDEPENDENTLY OF
THE THERMOSTAT (AUTO FAN OPERATES WITH Y1 ONLY), TWO
TRANSFORMERS MAY BE USED. SET SWITCH TO NONELECTRIC
POSITION.
5
POWER
SUPPLY
SUBBASE
LOGIC/
CONTROL
CIRCUIT
3
4
5
9
HIGH
LIMIT
HIGH
FAN
LIMIT
OPERATION
SWITCH
3
ELECTRIC
NON-ELECTRIC
2
SYSTEM
SWITCH
HEAT
OFF
COOL
COOL 1
FAN
SWITCH
AUTO
ON
FOR ELECTRIC HEAT APPLICATIONS (AUTO FAN OPERATES WITH W1
AND Y1), USE ONLY ONE TRANSFORMER; JUMPER R AND RC. SET
SWITCH TO ELECTRIC POSITION.
NOMINAL 24 VAC POWER MUST BE PRESENT BETWEEN R AND C FOR
THERMOSTAT OPERATION.
DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION.
T8624C,D
INSTALLATION
L1
(HOT)
1
HEATING
TRANSFORMER
R
4
C
W1
STAGE 1
HEAT RELAY
HEAT 1
W2
HEAT 2
STAGE 2
HEAT RELAY
B
HEATING DAMPER OR
CHANGEOVER RELAY
COOLING DAMPER OR
CHANGEOVER RELAY
O
STAGE 2
COOLING RELAY
Y2
COOL 2
STAGE 1
COOLING RELAY
Y1
FAN RELAY
G
3
RC
COOLING
TRANSFORMER
1
L1
(HOT)
M1016D
68-0134
L2
L2