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If ame is established but lost, the control will energize
the circulator blower at the heat speed and then begin a
new ignition sequence. If ame is established then lost on
subsequent attempts, the control will recycle for four (4)
consecutive ignition attempts (ve attempts total) before
locking out.
The diagnostic fault code is 1 ash for a lockout due to
failed ignition attempts or ame dropouts. The integrated
control will automatically reset after one hour, or it can be
reset by removing the thermostat signal or disconnecting
the electrical power supply for over ve seconds. If the
diagnostic LED indicates an external lockout, perform the
following checks:
• Check the supply and manifold gas pressures
• Check the gas orices for debris
• Check gas valve for proper operation
• Check 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.
• Check 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 ue 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 ame sensor
A drop in ame signal can be caused by nearly invisible
coating on the sensor. Remove the sensor and carefully
clean with steel wool.
• Check wiring
Check wiring for opens/shorts and miswiring.
IA pressure switch stuck open can be caused by a faulty
pressure switch, faulty wiring, a disconnected or damaged
hose, a blocked or restricted ue, 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 deenergized, the circulator blower heat o
cycle begins, and the induced draft blower remains on.
The diagnostic fault code is two ashes.
A stuck closed pressure switch can be caused by a faulty
pressure switch or faulty wiring. If the control encounters
a pressure switch stuck closed, the induced draft blower
remains o. The diagnostic LED code for this fault is three
(3) ashes.
If the primary limit switch opens, the gas valve is
immediately deenergized, the induced draft and air
circulating blowers are energized. The induced draft and
air circulator blowers remain energized until the limit switch
recloses. The diagnostic fault code for an open limit is four
(4) ashes.
A primary limit will open due to excessive supply air
temperatures. 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 automatically reset once the temperature falls
below a preset level.
If ame is detected with the gas valve deenergized, the
combustion and air circulator blowers are energized. The
diagnostic fault code is ve (5) ashes for this condition.
The control can be reset by removing the power supply
to the unit or it will automatically reset after one hour.
Miswiring is the probable cause for this fault.
The automatic ignition control has a built-in feature that
prevents damage to the compressor in short cycling
situations. In the event of intermittent power losses or
intermittent thermostat operation, the ignition control will
delay output to the compressor contactor for three minutes
from the time power is restored. (Compressor is o a total
of three minutes). The diagnostic LED will ash six (6)
times to indicate the compressor contactor output is being
delayed.
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