Amana GUIA Series Service Instructions Manual page 77

SYSTEM OPERATION
ABNORMAL OPERATION
(80% or 90% Models with White-Rodgers 50A50 or
Heatcraft HSI 1-1A Integrated Ignition Control)
The following presents the probable causes of questionable
furnace operation and how to fix them. Look through the
observation window in the blower access door and make a
note of the number of flashes in sequence between pauses.
Next, refer to the Diagnostic Signal Chart below for an inter-
pretation of the LED signals and to the information in this
section for a description of the problem.
1. Internal Control Failure with Integrated Ignition Con-
trol. If the control determines it has an internal fault, it
enters a locked-out state, and the diagnostic light will
light continuously with no flashes. The control should
be replaced.
2. System Lockout. If a flame is not sensed during the
first seven (7) seconds after the gas valve is energized,
the control turns off the gas. There will then be a 60
second delay while the induced draft blower is ener-
gized to purge the heat exchanger. The ignitor will next
be energized and preheated for 27 seconds. The gas
valve will then be energized. If flame is not sensed in
seven (7) seconds the gas valve will be de-energized
and another purge will occur. The control will cycle the
gas valve a total of three (3) times before it determines
it cannot establish measurable combustion and enters
a locked out state. If flame is sensed but lost after ten
(10) seconds, the control will recycle this series of three
tries four (4) more times before locking out. The diag-
nostic light code for this problem is one short flash
followed by a longer pause. The control can be reset
and brought out of lockout mode by turning the thermo-
stat off and then back on. It can also be reset by turning
off the electrical disconnect switch to the furnace for 30
seconds.
NOTE: The control board will automatically reset one hour
after lockout occurs. If the furnace frequently has to be re-
set, it means that a problem exists that should be corrected.
50A50 or HSI 1-1A INTEGRATED IGNITION CONTROL
DIAGNOSTIC SIGNAL CHART
FOR CORRECTIVE ACTION REFER TO
LIGHT SIGNAL
Continuous Light
1. Internal Control Failure
1 Flash 2. System Lockout
2 Flashes 3. Pressure Switch Stuck Closed
3 Flashes 4. Pressure Switch Stuck Open
4 Flashes 5. Open Limit Control
5 Flashes 6. Open Rollout Control
Continuous Flashing 7. Flame Sensed No Call For Heat
3. Pressure Switch Stuck Closed. If the control senses
the pressure switch is closed when the induced draft
blower is off, it waits until the fault is corrected. The di-
agnostic light code for this problem is two short flashes
followed by a longer pause. The probable cause is either
a faulty pressure switch or wiring.
4. Pressure Switch Stuck Open. If, after the induced draft
blower is energized, the pressure switch does not close,
the control will keep the blower on and wait for the switch
to close. The diagnostic light code for this problem is
three short flashes followed by a pause. The probable
cause is either disconnected hose to the pressure
switch, faulty pressure switch or wiring, or restricted air
intake or flue piping.
5. Open Limit Control. If the limit control opens, the air
circulator and induced draft blower will be turned on
until the limit closes. The diagnostic light code for this
problem is four short flashes followed by a pause. The
probable cause is either low conditioned air flow due to
dirty filter or resistance in duct work, faulty limit, faulty
blower, or blower speed set to low.
6. Open Rollout Control. If the rollout control opens, the
air circulator blower and induced draft blower will be
energized all the time. The diagnostic light code for this
problem is five flashes followed by a pause. The prob-
able cause is either restricted flue piping or improper
air requirements.
7. Flame Sensed with No Call for Heat. If the control
senses a flame when the gas valve is de-energized, it
will run the air circulator blower and the induced draft
blower continuously. The diagnostic light code for this
problem is continuous light flashing. The probable
causes are either a short to ground in flame sense cir-
cuit, miswiring, lingering burner flame or a slow closing
gas valve.
ABNORMAL OPERATION NUMBER
77
Rev. 1