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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.
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 Sensor
The pressure sensor is mounted near induced draft blower. Its
function is to regulate the induced draft blower's speed in order
to maintain proper air-fuel ratio for clean and reliable combustion.
The electrical output signal from the sensor is expected to be
proportional to the magnitude of the differential pressure between
the inducer inlet negative pressure and the ambient air pressure.
The pressure sensor also guards against insufficient airflow
(combustion air and flue products) through the heat exchanger.
At the beginning of a call for heat, the control ensures the inducer
is in an off state, then checks the pressure sensor output for the
proper null offset value. If the pressure sensor output is outside
the acceptable range for the null value, the control enters a five
minute lockout. After the lockout timer has expired, the control
resumes normal operation.
During inducer operation, including all operating modes except for
the null test, the control monitors the pressure sensor output for
expected values. The control limits during normal operation are
expected to be within certain tolerances of the target pressures.
In response to a pressure sensor span error, the control enters a
five minute lockout. After the lockout timer has expired, the control
resumes normal operation.
Primary Limit
A primary limit will open due to excessive supply air temperatures.
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 automatically reset once the
temperature falls below a preset level.
If a limit switch opens, the gas valve is immediately de-energized,
the induced draft and air circulating blowers are energized. The
induced draft and air circulator blowers remain energized for 5
minutes or until the limit switch re-closes, whichever happens first.
NOTE: If the primary limit opens three (3) times within the same
call for heat, the ignition control will lock out for one (1) hour with
the air circulating blower energized at high heat speed.
Flame Detected with Gas Valve Closed
If flame is detected with the gas 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 one hour. Miswiring is the probable
cause for this fault. The initial lockout period is 5 minutes. After
that time, the control continues to monitor the flame sense input
and resumes normal operation when flame is no longer sensed.
Low Flame Signal
Under some conditions, the fuel or air supply can create a nearly
invisible coating on the flame sensor. This coating acts as an insu-
lator 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.
Burner Switch
The burner temperature switch is mounted on the burner
assembly to monitor the burner box temperature. It is normally
closed (electrically), auto-reset sensor. This switch guards
against the burner flames not being properly drawn into the heat
exchanger.
The control senses an open blocked burner switch, indicating
that the burner temperature/pressure has exceeded its set point.
The control de-energizes the gas valve, energizes the inducer to
the pre-purge setting and energizes the indoor blower. The initial
lockout period is five minutes. After this time elapses, the control
evaluates the state of the blocked burner switch. If the switch is
closed, the control resumes normal operation. The control will
enter a one hour lockout state if the blocked burner switch fails to
reset before the recovery timer has expired.
ID Plug
The control operational parameters are stored in ID Plug which
connects on the circuit board. The control requires a valid ID
plug present to operate in heating mode. If a valid ID plug is not
present the control will not respond to a call for heat. However,
the control will respond to thermostat inputs "Y" or "G", operating
the appropriate fan output. The cooling delays are ignored in this
operating mode. The control puts the burner into hard lockout and
will not respond to heating requests until the power is cycled with
a valid ID plug installed.
Abnormal Operation - Cooling
Short Cycle Compressor Delay
In the event of intermittent power losses or intermittent thermostat
operation, the control system will delay output to the compressor
contactor for three minutes from the time power is restored or
thermostat call for cooling is restored. (Compressor is off a total
of three minutes).
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 electronic
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.
High Pressure Switch/Loss of Charge Switch
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.
Have the gas heating section of the unit checked at least once
a year before the heating season begins, to be sure that the
combustion air inlet and flue outlet hoods are not blocked by
debris, which would prevent adequate combustion air and a
properly operating vent system.
19
Maintenance
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