TWINNING CONNECTION DIAGRAM
FOR TWINNING S-SERIES FURNACES
2 STAGE HEAT / 1 STAGE COOLING
(WITH TRANSFORMER) THERMOSTAT
2 STAGE HEATING
1 STAGE COOLING
THERMOSTAT
FURNACE NO. 1
FURNACE NO. 2
R2
R2
ISOLATION RELAY
(FIELD SUPPLIED)
ISOLATION RELAY
R1
R1
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
O
N BOTH FURNACES, VOLTAGE SHOULD BE LESS THAN
10 VOLTS.
- IF GREATER, REVERSE THE LOW VOLTAGE ON ONE OF THE
T
RANSFORMERS AND RECHECK.
3. HEATING AND COOLING AIRFLOW MUST BE THE SAME FOR
BOTH FURNACES.
4. OD UNIT TYPE SETUP MUST BE SET FOR 1-1.
From Dwg. 21B341337 Rev. 2
OUTDOOR UNIT
(WITH TRANSFORMER)
RC
ISOLATION RELAY
(FIELD SUPPLIED)
ALTERNATE CONNECTION