16
Fig. 8—T8611M Thermostat with EM.HT.-HEAT-OFF-AUTO-COOL system and ON-AUTO fan switching;
EM.HT., CHECK, and AUX. HT. LEDS. Applied to 3-stage heat/2-stage cool system.
Fig. 9—T8611M Thermostat with EM.HT.-HEAT-OFF-AUTO-COOL system and ON-AUTO fan switching,
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
POSSIBLE CHECK LED CIRCUITS:
SOME OLDER HEAT PUMP THERMOSTATS USE X FOR COMMON TERMINAL.
NOMINAL 24 Vac POWER MUST BE PRESENT BETWEEN R AND C TERMINALS FOR THERMOSTAT OPERATION.
RECOMMENDED INTERCONNECT CABLE: 18-GAUGE THERMOSTAT CABLE, 200 ft. [61 m] MAXIMUM LENGTH. ROUTE
INTERCONNECT CABLE AWAY FROM SOURCES OF ELECTRICAL NOISE.
1
2
3
4
5
M1019D
MONITOR
AUXILIARY
HEAT RELAY
L1
(HOT)
L2
HEAT
OFF
AUTO
SYSTEM
SWITCH
COOL 1
AUTO
ON
FAN
SWITCH
4
1
R
C
L
W3
W2
E
G
O
B
Y
Y2
X2
EMERGENCY
HEAT RELAY
FAN RELAY
CHANGEOVER
RELAY (HEAT)
STAGE 1 COMPRESSOR
CONTACTOR
3
C.O.
EM. HT.
COOL
X1
CHANGEOVER
RELAY (COOL)
AUX. HEAT
LED (GRN)
HEAT 3
EM. HEAT
LED (RED)
HIGH
LIMIT
C.O.
HEAT 1
HIGH
LIMIT
CHECK LED
(YELLOW)
2
S1
S2
S3
S1
S2
S3
202905 REMOTE
SENSOR
5
X2
X1
CHECK
LED
(YELLOW)
FAULT DETECTION
SWITCH
SWITCH TO R (POWER) SIDE OF
SYSTEM TRANSFORMER
TO R
TO C
X2
X1
CHECK
LED
(YELLOW)
FAULT DETECTION
SWITCH
SWITCH TO C (COMMON) SIDE
OF SYSTEM TRANSFORMER
TO R
TO C
X2
X1
CHECK
LED
(YELLOW)
SWITCHING
DEVICE
SWITCH IN SECONDARY OF
SEPARATE TRANSFORMER
L1
(HOT)
L2
24 Vac 1
SUBBASE
LOGIC/
CONTROL
CIRCUIT
THERMOSTAT
LOGIC
CIRCUIT
POWER
SUPPLY
6
7
APPLICABLE ONLY ON MODEL WITH REMOTE SENSOR.
DENOTES THERMOSTAT TO SUBBASE INTERCONNECT.
6
7
HEAT 2
COOL 2
T8611M
INSTALLATION