Honeywell CHRONOTHERM T8621A - Manual (Page 10)

10
Fig. 9—T8621C 2-stage heat/1-stage cool thermostat with HEAT-AUTO-COOL-OFF system and AUTO-ON
fan switching.
NOMINAL 24 Vac POWER MUST BE PRESENT BETWEEN R AND C FOR
THERMOSTAT OPERATION.
DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION.
M5233
HEATING
TRANSFORMER
R
C
W1
W2
HEAT RELAY 1
HEAT RELAY 2
COOLING
TRANSFORMER
Y1
G
RC
COOLING
CONTACTOR
FAN RELAY
HEAT 1
HIGH
LIMIT
HIGH
LIMIT
L1
(HOT)
L2
HEAT
AUTO
OFF
SYSTEM
SWITCH
AUTO
ON
FAN
SWITCH
COOL
HEAT 2
2
1
COOL
L1
(HOT)
L2
1
2
1
2
3
4
3
4
SUBBASE
LOGIC/
CONTROL
CIRCUIT
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
FOR SINGLE TRANSFORMER SYSTEM JUMPER R AND RC.
POWER
SUPPLY
THERMOSTAT
LOGIC CIRCUIT
T8621A,C,D
INSTALLATION