Install Instructions

39

The burner ames should be inspected with the burner
compartment door installed. Flames should be stable,
quiet, soft, and blue (dust may cause orange tips but
they must not be yellow). Flames should extend directly
outward from the burners without curling, oating, or lifting
o󰀨. Flames must not impinge on the sides of the heat
exchanger ring tubes.

A number of safety circuits are employed to ensure safe
and proper furnace operation. These circuits serve to
control any potential safety hazards and serve as inputs
in the monitoring and diagnosis of abnormal function.
These circuits are continuously monitored during furnace
operation by the integrated control module.



The integrated control module is an electronic device
which, if a potential safety concern is detected, will
take the necessary precautions and provide diagnostic
information through an LED.

The primary limit control is located on the partition panel
and monitors heat exchanger compartment temperatures.
It is a normally-closed (electrically), automatic reset,
temperature-activated sensor. The limit guards against
overheating as a result of insu󰀩cient conditioned air
passing over the heat exchanger.

The auxiliary limit controls are located on or near the
circulator blower and monitors blower compartment
temperatures. They are a normally-closed (electrically),
manual-reset sensors. These limits guard against
overheating as a result of insu󰀩cient conditioned air
passing over the heat exchanger.

The rollout limit controls are mounted on the burner/
manifold assembly and monitor the burner ame. They are
normally-closed (electrically), manual-reset sensors. These
limits guard against burner ames not being properly
drawn into the heat exchanger.

The pressure switches are normally-open (closed during
operation) negative air pressure-activated switches. They
monitor the airow (combustion air and ue products)
through the heat exchanger via pressure taps located on
the induced draft blower and the coil front cover. These
switches guard against insu󰀩cient airow (combustion
air and ue products) through the heat exchanger and/or
blocked condensate drain conditions.

The ame sensor is a probe mounted to the burner/
manifold assembly which uses the principle of ame
rectication to determine the presence or absence of
ame.


The furnace should be inspected by a qualied installer, or
service agency at least once per year. This check should
be performed at the beginning of the heating season.
This will ensure that all furnace components are in proper
working order and that the heating system functions
appropriately. Pay particular attention to the following
items. Repair or service as necessary.
• Flue pipe system. Check for blockage and/or leakage.
Check the outside termination and the connections at
and internal to the furnace.
• Heat exchanger. Check for corrosion and/or buildup
within the heat exchanger passageways.
• Burners. Check for proper ignition, burner ame, and
ame sense.
• Drainage system. Check for blockage and/or leakage.
Check hose connections at and internal to furnace.
• Wiring. Check electrical connections for tightness
and/or corrosion. Check wires for damage.
• Filters.


Improper lter maintenance is the most common cause of
inadequate heating or cooling performance. Filters should
be cleaned (permanent) or replaced (disposable) every
two months or as required. When replacing a lter, it must
be replaced with a lter of the same type and size.

Depending on the installation, di󰀨ering lter arrangements
can be applied. Filters can be installed in either the central
return register or a side panel external lter rack (upow
only). A media air lter or electronic air cleaner can be
used as an alternate lter. Follow the lter sizes given in
the Recommended Minimum Filter size table to ensure
proper unit performance.
To remove lters from an external lter rack in an upright
upow installation, follow the directions provided with
external lter rack kit.