TWINNING CONNECTION DIAGRAM
FOR TWINNING S-SERIES FURNACES
2 STAGE HEAT / 1 STAGE COOLING THERMOSTAT
2 STAGE HEATING
1 STAGE COOLING
THERMOSTAT
FURNACE NO. 1
FURNACE NO. 2
R2
R2
ISOLATION RELAY
R1
R1
1 STAGE ODU
(NO TRANSFORMER)
Y1
B
Y1 Y1 Y1
W 1
W 1
W 1
W 2
W 2
W 2
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.
4. OD UNIT TYPE SETUP MUST BE THE SAME FOR BOTH FURNACES.