24
Remove the control box access panel and note the num-
ber of diagnostic LED flashes. Refer to Diagnostic Indicator
Chart for an interpretation of the signal and to this section
for an explanation.
i
nternal
c
OntrOl
f
ailure
If the integrated ignition control in this unit encounters an in-
ternal fault, it will go into a “hard” lockout and turn off the diag-
nostic LED. If diagnostic LED indicates an internal fault, check
power supply to unit for proper voltage, check all fuses, circuit
breakers and wiring. Disconnect electric power for five sec
-
onds. If LED remains off after restoring power, replace control.
a
bnOrmal
O
PeratiOn
- h
eating
c
Odes
External Lockout (1 FLASH CODE)
An external lockout occurs if the integrated ignition control de-
termines that a measurable combustion cannot be established
within three (3) consecutive ignition attempts. If flame is not
established within the seven (7) second trial for ignition, the
gas valve is deenergized, 15 second inter-purge cycle is com-
pleted, and ignition is reattempted. The control will repeat this
routine three times if a measurable combustion is not estab-
lished. The control will then shut off the induced draft blower
and go into a lockout state.
If flame is established but lost, the control will energize the cir
-
culator blower at the heat speed and then begin a new ignition
sequence. If flame is established then lost on subsequent at
-
tempts, the control will recycle for four (4) consecutive ignition
attempts (five attempts total) before locking out.
The diagnostic fault code is 1 flash for a lockout due to failed
ignition attempts or flame dropouts. The integrated control will
automatically reset after one hour, or it can be reset by remov-
ing the thermostat signal or disconnecting the electrical power
supply for over five seconds. If the diagnostic LED indicates an
external lockout, perform the following checks:
• Check the supply and manifold pressures
• Check the gas orifices for debris
• Check gas valve for proper operation
• Check secondary limit
A dirty filter, excessive duct static, insufficient air flow,
a faulty limit, or a failed circulator blower can cause this
limit to open. Check filters, 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 auxil-
iary limit to open. The automatic reset secondary limit
is located on top of the circulator blower assembly.
• Check rollout limit
If the burner flames are not properly drawn into the
heat exchanger, the flame rollout protection device will
open. Possible causes are restricted or blocked flue
passages, blocked or cracked heat exchanger, a failed
induced draft blower, or insufficient combustion air. The
rollout protection device is a manual reset limit located
on the burner bracket. The cause of the flame rollout
must be determined and corrected before resetting the
limit.
• Check flame sensor
A drop in flame signal can be caused by nearly invisible
coating on the sensor. Remove the sensor and careful-
ly clean with steel wool.
• Check wiring
Check wiring for opens/shorts and miswiring.
IMPORTANT:
If you have to frequently reset your gas/electric
package unit, it means that a problem exists that should be
corrected. Contact a qualified servicer for further information.
Pressure Switch Stuck Open (2 FLASH CODE)
IA pressure switch stuck open can be caused by a faulty
pressure switch, faulty wiring, a disconnected or damaged
hose, a blocked or restricted flue, 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 off cycle be-
gins, and the induced draft blower remains on. The diag-
nostic fault code is two flashes.
Pressure Switch Stuck Closed (3 FLASH CODE)
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 re-
mains off. The diagnostic LED code for this fault is three (3)
flashes.
Open Thermal Protection Device (4 FLASH CODE)
If the primary limit switch opens, the gas valve is immediate-
ly deenergized, the induced draft and air circulating blower-
sare energized. The induced draft and air circulator blow-
ers remain energized until the limit switch recloses. The
diagnostic fault code for an open limit is four (4) flashes.
A primary limit will open due to excessive supply air tem-
peratures. This can be caused by a dirty filter, excessive
duct static, insufficient air flow, or a faulty limit. Check filters,
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.
Flame Detected with Gas Valve Closed (5 FLASH CODE)
If flame is detected with the gas valve deenergized, the com
-
bustion and air circulator blowers are energized. The diag-
nostic fault code is five (5) flashes 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.
A
bnormAl
o
perAtion
- C
ooling
C
odes
Short Cycle Compressor Delay (6 FLASH CODE)
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. (Compressor is off a total of three minutes). The
diagnostic LED will flash six (6) times to indicate the com
-
pressor contactor output is being delayed.
NOTE:
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 five minutes to allow the
thermostat to complete its short cycle delay time.
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