
20
A drop in ame signal can be caused by nearly
invisible coating on the sensor. Remove the sensor
and carefully clean with steel wool.
• Auxiliary/Secondary Limit
A dirty lter, excessive duct static, insucient air
ow, a faulty limit, or a failed circulator blower can
cause this limit to open. Check lters, total external
duct static, circulator blower motor, blower motor
speed tap (see wiring diagram), and limit. An
interruption in electrical power during a heating
cycle may also cause the auxiliary limit to open.
The automatic reset secondary limit is located on
top of the circulator blower assembly.
• Rollout Limit
If the burner ames are not properly drawn into
the heat exchanger, the ame rollout protection
device will open. Possible causes are restricted
or blocked flue passages, blocked or cracked
heat exchanger, a failed induced draft blower, or
insucient combustion air. The rollout protection
device is a manual reset limit located on the burner
bracket. The cause of the ame rollout must be
determined and corrected before resetting the limit.
• Check wiring
Check wiring for opens/shorts and miswiring.
If you have to frequently reset your
gas/electric package unit, it means that a problem exists that
should be corrected. Contact a qualied servicer for further
information.
A pressure switch stuck open can be caused by a faulty
pressure switch, faulty wiring, a disconnected or damaged
hose, a blocked or restricted ue, a blocked pressure tap or
a faulty induced draft blower.
If the control senses an open pressure switch during the pre-
purge cycle, the induced draft blower only will be energized.
If the pressure switch opens after ignition has begun the gas
valve is de-energized, the circulator blower heat o cycle
begins, and the induced draft blower remains on. The diag-
nostic LED (red) code is two (2) ashes.
A stuck closed pressure switch can be caused by a faulty pres-
sure switch or faulty wiring. If the control encounters a pressure
switch stuck closed, the induced draft blower remains o. The
diagnostic red LED code for this fault is three (3) ashes.
A primary limit will open due to excessive supply air tem-
peratures. This can be caused by a dirty lter, excessive
duct static, insucient air ow, or a faulty limit. Check lters,
total external duct static, blower motor, blower motor speed
tap (see wiring diagram), and limit. This limit will automati-
cally reset once the temperature falls below a preset level.
If a limit switch opens, the gas valve is immediately de-en-
ergized, the induced draft and air circulating blowers are en-
ergized. The induced draft and air circulator blowers remain
energized until the limit switch re-closes. The diagnostic
LED (red) code for an open limit is four (4) ashes.
If the primary limit opens ve (5) times within the
same call for heat, the ignition control will lock out for one
(1) hour with the air circulating blower energized at high heat
speed. The diagnostic LED (red) code for this condition is
seven (7) ashes.
If ame is detected with the gas valve de-energized, the
combustion and air circulator blowers are energized. The di-
agnostic fault code is ve (5) ashes (red LED) for this con-
dition. The ame diagnostic LED (amber) will ash (2) times
to indicate this condition. The control can be reset by remov-
ing the power supply to the unit or it will automatically reset
after one hour. Miswiring is the probable cause for this fault.
Under some conditions, the fuel or air supply can create a
nearly invisible coating on the ame sensor. This coating
acts as an insulator causing a drop in the ame signal. If the
ame signal drops below a predetermined value, the ignition
control will display an error code of (1) ash on the amber
diagnostic LED. The unit will continue to operate until the
control can no longer detect ame.
The automatic ignition control has a built-in feature that pre-
vents damage to the compressor in short cycling situations.
In the event of intermittent power losses or intermittent ther-
mostat operation, the ignition control will delay output to the
compressor contactor for three minutes from the time power
is restored or thermostat call for cooling is restored. (Com-
pressor is o a total of three minutes). The diagnostic red
LED will ash six (6) times to indicate the compressor con-
tactor output is being delayed.
Some electronic thermostats also have a built-in
compressor short cycle timer that may be longer than the
three minute delay given above. If you are using an elec-
tronic thermostat and the compressor has not started after
three minutes, wait an additional ve minutes to allow the
thermostat to complete its short cycle delay time.
Some models include a high pressure cutout switch and/
or a loss of charge cutout switch. The high pressure cutout
switch protects the refrigeration system from excessive op-
erating pressures. The loss of charge cutout switch protects
the refrigeration system from very low operating pressures
due to a loss of refrigerant. Compressor operation will be
disabled if either of these devices opens. If either devices
opens, the diagnostic red LED will ash (9) times to indicate
that a refrigeration system pressure switch is open.