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Pressure Switch Stuck Open—2 Flashes (Red LED)
Causes:
Faulty pressure switch
Faulty wiring
Disconnected or damaged hose
Blocked or restricted flue
Faulty induced draft blower
If the control senses an open pressure switch during the pre-
purge cycle, the induced draft blower will be energized only.
If the pressure switch opens after ignition has begun, the gas
control valve is de-energized, the circulator blower Heat Off cycle
begins and the induced draft blower remains on.
Pressure Switch Stuck Closed—3 Flashes (Red LED)
Causes:
Faulty pressure switch
Faulty wiring
If the control encounters a pressure switch stuck closed, the
induced draft blower remains off.
Open Thermal Protection Device—4 Flashes (Red LED)
If a limit switch opens, the gas control valve is immediately de-
energized, and the induced draft and air circulating blowers are
energized. The induced draft and air circulator blowers remain
energized until the limit switch closes again.
Primary Limit Switch
A primary limit switch will open due to excessive supply air
temperatures possibly caused by:
A dirty filter—Check filters.
Excessive duct static—Check total external duct static.
Insufficient airflow—Check blower motor and motor speed
tap (see wiring diagram).
A faulty limit switch—Check limit switch
NOTE: This limit switch will automatically reset once the
temperature falls below a preset level.
Auxiliary/Secondary Limit Switch
An auxiliary/secondary limit switch will open due to:
A dirty filter—Check filters.
Excessive duct static—Check total external duct static.
Insufficient airflow—Check circulator blower motor and motor
speed tap (see wiring diagram).
A faulty limit switch—Check limit switch.
A failed circulator blower—Replace circulator blower.
An interruption in electrical power during a heating cycle—
Automatic reset secondary limit switch is located on top of
the circulator blower assembly.
Rollout Limit Switch
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
Failed induced draft blower
Insufficient combustion air.
NOTE: The rollout limit switch is a manual reset limit switch
located on the burner bracket. The cause of the flame rollout
must be determined and corrected before resetting the limit.
Flame Detected with Gas Control Valve Closed—5
Flashes (Red LED)—2 Flashes (Amber LED)
If a flame is detected with the gas control valve de-energized, the
combustion and air circulator blowers are energized.
The control can be reset by removing the power supply to the
unit or it will automatically reset after 1 hour. Incorrect wiring is
the probable cause for this fault.
Low Flame Signal—1 Flash (Amber LED)
Under some conditions, the fuel or air supply can create a nearly
invisible coating on the flame sensor. This coating acts as an
insulator causing a drop in the flame signal. If the flame signal
drops below a predetermined value, the ignition control will
display an error code of (1) flash on the amber diagnostic LED.
The unit will continue to operate until the control can no longer
detect flame.
Abnormal Operation—Cooling
Short Cycle Compressor Delay—6 Flashes (Red LED)
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 3 minutes from the time power is restored or
thermostat call for cooling is restored. Compressor is off a total of
3 minutes.
NOTE: Some electronic thermostats also have a built-in
compressor short cycle timer that may be longer than the
3-minute delay given above. If you are using an electronic
thermostat and the compressor has not started after 3 minutes,
wait an additional 5 minutes to allow the thermostat to complete
its short cycle delay time.
High Pressure Switch/Loss of Charge Switch—9 Flashes
(Red LED)
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 operating
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.
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