Installation - Honeywell CHRONOTHERM T8621A User Manual

T8621A,C,D

INSTALLATION

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