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Low Voltage Wiring
Install the thermostat per the manufacturer's instructions.
The low voltage (24 volt) connections from the thermostat
are made at the terminal strip on the integrated control in
the furnace. See Figure 18 for the proper connections for
heating only (two-wire) and heating/cooling (four-wire)
applications. The recommended minimum wire gauge for
thermostat wiring is shown in Table 10.
The thermostat must not be installed on an outside wall or
any other location where its operation may be adversely
affected. Adverse affects include radiant loading from
fireplaces, sunlight, or lighting fixtures, and convective
loading from warm air registers or electrical appliances.
To determine the heat anticipator setting either:
1.
Add the current draw of the system components; or
2.
Measure the current flow on the thermostat R-W
circuit after the circulating blower motor has started.
Set the heat anticipator according to the thermostat
manufacturer's instructions for heat anticipator settings.
START-UP AND ADJUSTMENTS
General
Prior to start-up, verify that:
1.
The line voltage power leads are securely connected,
that the polarity of the connections is correct, and
that the furnace is properly grounded.
2.
The thermostat wires (R, W, Y, and G) are securely
connected to the correct leads on the terminal strip
of the circuit board.
3.
The gas line service pressure does not exceed 10.0
in. water column (0.36 psig), and is not less than 4.5
in. water column (0.16 psig) for natural gas. For LP
gas the line service pressure must not exceed 14 in.
water column (0.51 psig), and must not be less than
11.0 in. w.c. (0.40 psig).
4.
The roll-out and vent safety manual reset switches
are closed. If necessary, press the red button to
reset a switch. DO NOT install a jumper wire across
White (Neutral)
Green or Bare
24
Field Supplied
Field Supplied
Fused Service
Panel Connector
Panel
Black (Hot)
Black
White
(Ground)
Ground
Field Supplied Disconnect
Within Sight of Furnace
Figure 22. Line Voltage Field Wiring
a switch to defeat its function. If a switch reopens
on start-up, DO NOT reset the switch without
identifying and correcting the fault condition which
caused the switch to trip.
5.
The blower door is in place, closing the door switch
in the line voltage circuit.
6.
The gas line has been purged and all connections are
leak tight.
Start-up Procedures
After all of the above checks have been made:
1.
Set the thermostat to the lowest setting.
2.
Close the disconnect(s) to provide line voltage to the
furnace.
3.
Follow the procedures given on the operating
instruction label attached to the furnace.
4.
Set the thermostat above room temperature and
verify the operating sequence. (See the Sequence
of Operation).
5.
After the furnace has run for approximately five
minutes, set the thermostat below room temperature
and verify steps (9) through (11) of the Sequence of
Operation.
Verifying and Adjusting Firing Rate
The firing rate must be verified for each installation to
prevent over-firing the furnace.
IMPORTANT NOTE:
The firing rate must not exceed the rate shown on the
furnace rating plate. At altitudes above 2000 feet it must
not exceed that on the rating plate less 4% for each 1000
feet.
Follow the procedure below to determine the firing rate.
1.
Shut off all other gas fired appliances.
2.
Start the furnace and allow it to run for at least three
minutes.
Black
Black
White
White
Ground
Ground
Junction Box (may be internal
or external to the furnace). These
connections can be made in the
field supplied disconnect at the
furnace.
Field Line Voltage
Wiring
Factory Line
Voltage Wiring
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