GPG16M Installation Instructions

18
FAULT RECALL
The ignition control is equipped with a momentary push-button switch that can be used to display on the diagnostic LED the last five
faults detected by the control. The control must be in Standby Mode (no thermostat inputs) to use the feature. Depress the push-button
switch for approximately 2 seconds. NOTE: Do not hold for longer than 4 seconds. Holding the button for 4 seconds or higher will
erase the memory! Release the switch when the LED is turned off. The diagnostic LED will then display the flash codes associated with
the last five detected faults. The order of display is the most recent fault to the least recent fault.
ABNORMAL OPERATION - HEATING
INTERNAL CONTROL FAILURE
If the integrated ignition control in this unit encounters an internal fault, it will go into a “hard” lockout and turn off the diagnostic 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 seconds. If LED remains off after restoring power, replace control.
EXTERNAL LOCKOUT
An external lockout occurs if the integrated ignition control determines 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 de-
energized, 30 second inter-purge cycle is completed, and ignition is re-attempted. The control will repeat this routine three times if a
measurable combustion is not established. 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 circulator blower at the heat speed and then begin a new ignition sequence.
If flame is established then lost on subsequent attempts, the control will recycle the ignition sequence.
The diagnostic fault code is 1 flash for a lockout due to failed ignition attempts. 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 five seconds.
If the diagnostic red 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 flame sensor
A drop in flame 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 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 auxiliary limit to open. The
automatic reset secondary limit is located on top of the circulator blower assembly.
• 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 wiring
Check wiring for opens/shorts and miswiring.
IMPORTANT NOTE: 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
A pressure switch stuck open can be caused by a faulty pressure switch, faulty wiring, a disconnected or damaged hose, a blocked
or restricted flue, 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 off cycle begins, and the induced draft
blower remains on. The diagnostic LED (red) code is two (2) flashes.
PRESSURE SWITCH STUCK CLOSED
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 off. The diagnostic red LED code for this fault is three (3) flashes.