17
Cooling Operation
NOTE:
Mechanical cooling cannot be reliably provided at ambient temperatures below 50° F.
1. Turn on the electrical power supply to the unit.
2. Place the room thermostat selector switch in the COOL position (or AUTO if available, and if automatic changeover from
cooling to heating is desired).
3. Set the room thermostat to the desired temperature.
TROUBLESHOOTING
I
GNITION
C
ONTROL
E
RROR
C
ODES
The following presents probable causes of questionable unit operation. Refer to
Diagnostic Indicator Chart
for an interpretation of
the signal and to this section for an explanation.
Remove the control box access panel and note the number of diagnostic LED flashes. Refer to
Diagnostic Indicator Chart
for an
interpretation of the signal and to this section for an explanation.
F
AULT
R
ECALL
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.
A
BNORMAL
O
PERATION
- H
EATING
I
NTERNAL
C
ONTROL
F
AILURE
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.
E
XTERNAL
L
OCKOUT
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.
P
RESSURE
S
WITCH
S
TUCK
O
PEN
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.
