Installation manual

272313-UIM-A-0407
Unitary Products Group 13
Twinning Operation
Heating - On a call for low-stage heat (W1 signal) from the wall thermo-
stat, both furnaces will start the ignition sequence and the burners on
both furnaces will light and run at low fire. After a short delay, both blow-
ers will come on and operate at the low heat speed. On a call for high-
stage heat (W2 signal), both furnaces will operate at high fire and both
blowers will operate at the high cool setting. When the thermostat is sat-
isfied, the burners of both furnaces will shut off and, after the selected
blower delay time, both blowers will shut off at the same time.
Cooling - On a call for cooling (Y1 or Y1+Y2 signal) from the wall ther-
mostat, both furnace blowers will come on at the same time and will run
at the appropriate cooling speed. After the thermostat is satisfied, both
blowers will stay on for 60 seconds and then will shut off at the same
time.
Continuous Fan - On a call for continuous fan (G signal) from the wall
thermostat, both blowers will come on in the selected continuous fan
speed and will stay on until the G signal is removed.
SECTION VI: COMBUSTION AIR AND
VENT SYSTEM
COMBUSTION AIR AND VENT SAFETY
This Category IV, dual certified direct vent furnace is designed for resi-
dential application. It may be installed without modification to the con-
densate system in a basement, garage, equipment room, alcove, attic
or any other indoor location provided the space temperature is 32 °F
(0°C) or higher and where all required clearance to combustibles and
other restrictions are met. The combustion air and the venting system
must be installed in accordance with Section 5.3, Air for Combustion
and Ventilation, of the National Fuel Gas Code Z223.1/NFPA 54 (latest
edition), or Sections 7.2, 7.3 or 7.4 of CSA B149.1, National Gas and
Propane Codes (latest edition) or applicable provisions of the local
building code and these instructions.
IMPORTANT: The “VENT SYSTEM” must be installed as specified in
these instructions for Residential and Non HUD Modular Homes. The
sealed combustion air / vent system is the only configuration that can
be installed in a Non HUD Modular Home.
FIGURE 8: Twinning Wiring Diagram - 1H/1C Thermostat
FIGURE 9: Twinning Wiring Diagram - 2H/1C Thermostat
FIGURE 10: Twinning Wiring Diagram - 2H/2C Thermostat
Y/Y2
W/W1
W2
R
G
TWIN
TO A/C
1H/1C THERMOSTAT
WG
R
Y
W2 RELAY
FURNACE 2
TWIN
FURNACE 1
Y1
C
Y/Y2
W/W1
W2
R
G
Y1
C
W1 RELAY
Y/Y2
W/W1
W2
R
G
TWIN
TO A/C
2H/1C THERMOSTAT
W2 G
R
Y
W2 RELAY
FURNACE 2
TWIN
FURNACE 1
Y1
C
Y/Y2
W/W1
W2
R
G
Y1
C
W1 RELAY
W1
Y/Y2
W/W1
W2
R
G
TWIN
TO
TWO-STAGE
A/C
2H/2C THERMOSTAT
W2 G
R
Y1
W2 RELAY
FURNACE 2
TWIN
FURNACE 1
Y1
C
Y/Y2
W/W1
W2
R
G
Y1
C
W1 RELAY
W1
Y2
This furnace may not be common vented with any other appliance,
since it requires separate, properly sized air intake and vent lines.
The furnace shall not be connected to any type of B, BW or L vent
or vent connector, and not connected to any portion of a factory-
built or masonry chimney
The furnace shall not be connected to a chimney flue serving a sep-
arate appliance designed to burn solid fuel.
When combustion air pipe is installed above a suspended ceiling or
when it passes through a warm and humid space, the pipe must be
insulated with 1/2” Armaflex or other heat resistant type insulation.
Vent piping must be insulated with 1/2” insulation if it will be sub-
jected to freezing temperatures such as routing through unheated
areas or through an unused chimney.