Single Wire Twinning - For Models With Twin Terminals - American Standard *UD Series Operation Manual

Single Wire Twinning – For Models with Twin Terminals
Twinning Connection Diagram for Twinning 1 Stage Furnaces
with Single Wire Twinning Feature 1 Stage Heating Only Thermostat
FURNACE NO. 1
INTEGRATED FURNACE
CONTROL
TWIN Y W G
R
R1
ISOLATION
RELAY
(FIELD SUPPLIED)
SEE NOTE 4
W G C/B
R
1 STAGE
HEATING ONLY
THERMOSTAT
(WITH FAN SWITCH)
Twinning Connection Diagram for Twinning 1 Stage Furnaces
with Single Wire Twinning Feature 1 Stage Heating/1 Stage Cooling Thermostat
FURNACE NO. 1
INTEGRATED FURNACE
CONTROL
TWIN Y W G
R
R1
ISOLATION
RELAY
(FIELD SUPPLIED)
SEE NOTE 4
Y W R G C/B
1 STAGE
HEATING/COOLING
THERMOSTAT
INTEGRATED FURNACE
BLOWER OPERATION OF UNIT NO. 2
IS SYNCHRONIZED WITH UNIT NO. 1
VIA SIGNALS FROM "TWIN" CONNECTION
C TWIN Y
SEE NOTE 4
SEE NOTE 3
ALTERNATE WIRING CONFIGURATION
SEE NOTE 4
INTEGRATED FURNACE
BLOWER OPERATION OF UNIT NO. 2
IS SYNCHRONIZED WITH UNIT NO. 1
VIA SIGNALS FROM "TWIN" CONNECTION
C TWIN Y
SEE NOTE 4
SEE NOTE 3
RC
ISOLATION
RELAY
(FIELD SUPPLIED)
SEE NOTE 3
NOTES:
1. BOTH FURNACES MUST BE POWERED FROM THE SAME 115V. LEG
OF CIRCUIT PANEL.
FURNACE NO. 2
2. INSURE 24V. FURNACE TRANSFORMERS ARE IN PHASE. PRIOR TO
COMPLETING CONNECTIONS, CHECK VOLTAGE BETWEEN "R"
CONTROL
TERMINALS OF EACH FURNACE. IF VOLTAGE IS GREATER THAN
10V., REVERSE THE "BL" AND "RD" SECONDARY LEADS ON ONE OF
THE FURNACE TRANSFORMERS.
3. CONNECTION MAY BE REQUIRED FOR ELECTRONIC THERMOSTAT.
W G C 4. IF CURRENT EXCEEDS THERMOSTAT CURRENT RATING, USE
R
ISOLATION RELAYS "RI" AS SHOWN. (DO NOT CONNECT "W"
TO "W") ISOLATION RELAY NOT NEEDED IF THE THERMOSTAT
CONTACTS ARE RATED AT 1.OA. OR ABOVE.
ISOLATION Twinning requires that two
R1 RELAY
furnaces with the same configu-
SEE NOTE 4
ration, capacity and airflow
must be used. They shall have
common returns with equal
pressure drops or ducts with
equivalent lengths and sizes.
NOTES:
1. BOTH FURNACES MUST BE POWERED FROM THE SAME 115V. LEG
FURNACE NO. 2
OF CIRCUIT PANEL.
2. INSURE 24V. FURNACE TRANSFORMERS ARE IN PHASE. PRIOR
TO COMPLETING CONNECTIONS, CHECK VOLTAGE BETWEEN "R"
CONTROL
TERMINALS OF EACH FURNACE. IF VOLTAGE IS GREATER THAN
10V., REVERSE THE "BL" AND "RD" SECONDARY LEADS ON ONE OF
THE FURNACE TRANSFORMERS.
3. IF OUTDOOR UNIT HAS A 24V. TRANSFORMER, AN ISOLATION
W G C
R RELAY MUST BE INSTALLED. (FIELD SUPPLIED – USE PILOT DUTY
RELAY "RC", SUCH AS RLY0975.) SEE ALTERNATE CONNECTION.
4. IF CURRENT EXCEEDS THERMOSTAT CURRENT RATING, USE
ISOLATION RELAYS "RI" AS SHOWN. (DO NOT CONNECT "W"
TO "W") ISOLATION RELAY NOT NEEDED IF THE THERMOSTAT
CONTACTS ARE RATED AT 1.OA. OR ABOVE.
5. CONNECTION MAY BE REQUIRED FOR ELECTRONIC THERMOSTATS.
ISOLATION
R1 RELAY
SEE NOTE 4
B
OUTDOOR UNIT
(NO TRANSFORMER)
Y
R
OUTDOOR UNIT
(WITH TRANSFORMER)
Y
ALTERNATE WIRING
CONFIGURATION
SEE NOTE 4
38
From Dwg. 21B341422 Rev. 1
From Dwg. 21B341423 Rev. 1