60
88-A951X001-1B-EN
Twinning
TWINNING CONNECTION DIAGRAM
1 STAGE HEAT / 1 STAGE COOLING THERMOSTAT
1 STAGE HEATING
1 STAGE COOLING
THERMOSTAT
FURNACE NO. 1
FURNACE NO. 2
ISOLATION RELAY
R1
R1
1 STAGE ODU
(NO TRANSFORMER)
Y1
B
Y1
Y1
Y1
W 1
W 1
W 1
R
R
R
G
G
G
B
B
B
NOTES:
1. BOTH FURNACES MUST BE POWERED FROM
THE SAME 115 VAC PHASE LEG AT THE CIRCUIT BREAKER.
2. TRANSFORMERS MUST BE IN PHASE.
- MEASURE THE VOLTAGE BETWEEN THE “R” TERMINALS
ON BOTH FURNACES, VOLTAGE SHOULD BE LESS THAN
10 VOLTS.
- IF GREATER, REVERSE THE LOW VOLTAGE ON ONE OF THE
TRANSFORMERS AND RECHECK.
3. HEATING AND COOLING AIRFLOW MUST BE THE SAME FOR
BOTH FURNACES.
TWINNING CONNECTION DIAGRAM
1 STAGE HEAT / 1 STAGE COOLING
(WITH TRANSFORMER) THERMOSTAT
1 STAGE HEATING
1 STAGE COOLING
THERMOSTAT
FURNACE NO. 1
FURNACE NO. 2
ISOLATION RELAY
(FIELD SUPPLIED)
ISOLATION RELAY
R1
R1
Y1
B
Y1
Y1
Y1
W 1
W 1
W 1
R
R
R
G
G
G
B
B
B
NOTES:
1. BOTH FURNACES MUST BE POWERED FROM
THE SAME 115 VAC PHASE LEG AT THE CIRCUIT BREAKER.
2. TRANSFORMERS MUST BE IN PHASE.
- MEASURE THE VOLTAGE BETWEEN THE “R” TERMINALS
ON BOTH FURNACES, VOLTAGE SHOULD BE LESS THAN
10 VOLTS.
- IF GREATER, REVERSE THE LOW VOLTAGE ON ONE OF THE
TRANSFORMERS AND RECHECK.
3. HEATING AND COOLING AIRFLOW MUST BE THE SAME FOR
BOTH FURNACES.
From Dwg. 21B341337 Rev. 2
OUTDOOR UNIT
(WITH TRANSFORMER)
RC
ISOLATION RELAY
(FIELD SUPPLIED)
ALTERNATE CONNECTION