15
SIDEWALL VENTING
For applications where vertical Category I venting is
not possible, the only recommended method of
sidewall venting is through the use of an accessory
power venter. Only power venters approved by a
nationally recognized approval agency may be used.
Approved power venters are Tjernlund Models
GPAK-JT or GPAK-1T and Field Controls Models
PVG-2 or SWG-4HD. For installation details, follow
the installation instructions supplied with the power
venter.
When sidewall venting these furnaces with a
power venter, it is required that a barometric
draft damper be installed in the vent near the
furnace. Failure to do so could cause a mal-
function of the furnace resulting in asphyxiation.
NOTE: It is recommended that a post-purge timer
be used. This is a device that keeps the
power venter in operation for a short period
at the end of each burner cycle in order to
clear out all flue gases from the vent.
Manufacturers of power venters also can
supply post-purge timers.
ELECTRICAL WIRING
All internal wiring has been made at the factory.
Field wiring requires only the connection of line
voltage supply wiring and low voltage thermostat
wiring.
Service wiring and control wiring may be brought
into the furnace through either side using the holes
provided.
Refer to the unit rating plate and specification tables
found in these instructions for applicable electrical
characteristics and requirements. A complete wiring
diagram is supplied on page 20.
Service wiring
Field wiring connections should be made inside the
furnace casing and a suitable strain relief should be
used at the point the wires exit the furnace casing. In
order for the electrical controls in the furnace to
operate properly, correct electrical polarity must be
observed. If the furnace does not work on initial
start-up and the diagnostic light on the furnace
control flashes six times, the polarity is reversed.
Field wiring of the unit should conform to local codes
or in the absence of local codes with the National
Electrical Code ANSI/NFPA 70. In Canada, field
wiring of the unit should conform to local codes or in
the absence of local codes with the Canadian
Electrical Code, Part I, and CSA C22.1.
A separate fused circuit from the main electrical
panel should serve only the furnace.
Electrical Grounding
The furnace casing must have an uninterrupted
electrical ground in accordance with the National
Electrical Code ANSI/NFPA 70 or, in Canada, with
the Canadian Electrical Code, Part I, and CSA
C22.1. DO NOT use gas piping as an electrical
ground.
Control Wiring
The thermostat should be installed in accordance
with the manufacturer’s instructions, furnished with
the thermostat, and make connections to the unit as
shown on the unit-wiring diagram. It is recom-
mended that size 18 AWG wire be used.
Heat Anticipator
If the wall thermostat has an adjustable heat
anticipator, the setting should be .48 amps. If any
accessories are to be connected to the furnace, the
heat anticipator setting may change. Use a suitable
ammeter to measure the actual anticipator current.
Accessories
A humidifier or electronic air cleaner may be used
with this furnace. All accessories should be wired
according to the manufacturer’s instructions.
The furnace control board has a terminal marked
EAC, which may be used to power an electronic air
cleaner accessory. This terminal is energized with
115 volts whenever the furnace circulating air blower
is operating in either heating or cooling speed.
The furnace control board has a terminal marked
HUM, which may be used to power an humidifier
accessory. This terminal is energized with 115 volts
whenever the wall thermostat calls for heat.
Make sure that the total load on the furnace trans-
former does not exceed 40 VA, including gas valve,
furnace relays, accessories, and air conditioner
loads.
Do not attempt to wire an electronic air cleaner into
the furnace blower relay. Damage to the furnace
blower motor may result.
Twinning
When two furnaces are installed using the same
duct system, it is very important that the two furnace
circulating air blowers operate simultaneously. If one
blower starts before the second blower, the duct
system will become pressurized with air and the
second blower will be made to turn backwards.
During heating operation, this will cause overheating
of the second furnace, possibly causing an unsafe
condition and damage to the furnace. If twinning of
two furnaces is desired, it is necessary to use the
accessory twinning kit that is designed for use with
these furnaces. The accessory twinning kit is
available from your distributor.