Installation manual

ManualsBrandsYork ManualsFurnace92% GY 9 (Upflow)

035-17736-003 Rev. A (0504)

10 Unitary Products Group

Continuous Fan - On a thermostat call for continuous fan (G signal),

both furnace blowers will come on at the same time in cooling speed

and will stay on until the G signal is removed.

STAGING

In applications where more heating capacity or more airflow capacity is

needed than what one furnace can deliver, twinning can be used to

make two furnaces operate in tandem, using one duct system and one

room thermostat. This control can also be used along with a two-stage

wall thermostat to stage two twinned furnaces, making them operate

like a single two-stage furnace. This allows only one furnace to supply

heat during times when the heat output from one furnace is sufficient to

satisfy the demand. When one duct system is used for two furnaces, it

is necessary that the two blowers operate in unison. The twinning func-

tion of this board ensures that both blowers turn on and off simulta-

neously, and operate on the same blower speed. Even when only one

furnace is supplying heat, both furnace blowers must run.

Single-Wire Staging

The single-wire twinning feature of this board can also be used for stag-

ing of two furnaces. With this feature, a single wire is connected

between the TWIN terminal on one furnace board to the TWIN terminal

on the second furnace board. The board then communicates the blower

status from one furnace to the other along this wire. This communica-

tion makes the second furnace blower come on at the same time, and

on the same speed, as the first furnace blower.

Single-Wire Staging Instructions

Connect the control wiring as shown in the Figure 11.

1. Connect the low voltage wiring from the wall thermostat to the ter-

minal strip on the control board of Furnace #1. For staging applica-

tions, the wire from thermostat W1 is connected to the W

connection on the board on Furnace #1. The wire from thermostat

W2 is connected to Furnace #2 through a separate relay, as

described below.

2. Connect a wire from the TWIN terminal of Furnace #1 to the TWIN

terminal of Furnace #2.

3. Install a separate 24V relay as shown in the diagram below. Use of

this relay is required, as it ensures that the transformers of the two

furnaces are isolated, thus preventing the possibility of any safety

devices being bypassed.

Single-Wire Staging Operation

Heating - On a call for first-stage heat (W1 signal) from the wall thermo-

stat, Furnace #1 will start the ignition sequence and the burners will

light. About thirty seconds after the burners light, the blowers on both

furnaces will come on in heating speed. When the thermostat is satis-

fied, the burners will shut off and, after the selected blower off delay

time, both blowers will shut off at the same time. On a call for second

stage of heat, the burners of Furnace #2 will also light and both blowers

will run. The twinning control ensures that both blowers come on and

shut off at the same time.

Cooling - On a call for cooling (Y signal) from the wall thermostat, both

furnace blowers will come on at the same time. When the thermostat is

satisfied, both blowers will stay on for 60 seconds, then will shut off at

the same time.

Continuous Fan - On a thermostat call for continuous fan (G signal),

both furnace blowers will come on at the same time in cooling speed

and will stay on until the G signal is removed.

SECTION VII: 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 where all required clearance to combusti-

bles and other restrictions are met. The combustion air and the venting

system must be installed in accordance with Section 5.3, Air for Com-

bustion 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 10: Single Stage Twinning Wiring Diagram

TWIN

TO A/C

WALL THERMOSTAT

ISOLATION

RELAY

FURNACE 2 CONTROL BOARD

TWIN

FURNACE 1 CONTROL BOARD

FIGURE 11: Two-Stage Twinning Wiring Diagram

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 if

two feet or more of pipe is exposed.

Vent piping must be insulated if it will be subjected to freezing tem-

peratures such as routing through unheated areas or through an

unused chimney.

TWIN

TO A/C

WALL THERMOSTAT

W1 G

ISOLATION

RELAY

FURNACE 2 CONTROL BOARD

TWIN

FURNACE 1 CONTROL BOARD