Amana GUIA Series Service Instructions Manual page 107

SYSTEM OPERATION
Abnormal Operation
(90% Two-Stage Models with White- Rodgers 50M61-
288 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 Troubleshooting Chart on the following
page for an interpretation of the LED signals and to the
information in this section for a description of the problem.
1. Internal Control Failure with Integrated Ignition
Control. 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 energized
to purge the heat exchanger. The ignitor will next be
energized and preheated for 20 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) sec-
onds, the control will recycle this series of three tries
five (5) more times before locking out. The diagnostic
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 thermostat off and
then back on. It can also be reset by turning off the elec-
trical 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.
Refer to Troubleshooting Chart on the following pages for
aid in determining the cause.
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 induced draft 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 causes are either a blocked,
pinched or disconnected hose to the pressure switch,
faulty pressure switch or loosse or misconnected wir-
ing, restricted air intake or flue piping, blocked drain
system or weak induced draft blower.
5. Open Primary, Auxiliary or Rollout Limit. If the limit
control opens, the air circulator 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 for either an open primary or auxiliary
limit is low conditioned air flow due to dirty filter or resis-
tance in duct work, faulty limit, faulty blower, blower
speed set to low or loose or misconnected wiring. The
rollout limit(s) is(are) open due to flame rollout. The prob-
able cause for an open rollout limit is misaligned burn-
ers, blocked flue and/or air inlet pipe, failed induced draft
blower or loose or misconnected wiring.
6. Reversed Polarity. If the 115V or 24V AC power leads
are reversed, the furnace will fail to operate. The diag-
nostic light code for this problem is six flashes followed
by a pause. The probable cause is either the 115V AC
power to furnace or integrated control module is reversed,
the 24V AC orange and gray wires to transformer are
reversed, or poor unit ground.
7. Low Flame Sense Signal. If the furnace continues to
operate and the micro-amp signal from the flame sensor
falls below specified level. The diagnostic light code for
this problem is seven flashes followed by a pause. The
probable cause is either a coated/oxidized sensor, in-
correctly positioned senser in burner flame or lazy burner
flame due to improper gas pressure or combustion air.
8. Ignitor Circuit Problem. If the furnace fails to operate
due to a problem with the ignitor. The diagnostic code
for this problem is eight flashes followed by a pause.
The probable cause is either loose or misconnected wir-
ing or a bad ignitor.
9. Furnace Operating on Low Stage Gas with High
Stage Induced Draft Blower and High Stage Circu-
lator Blower. If the furnaces high stage pressure switch
circuit fails to close in rspone to hihg stage induced draft
blower operation. The diagnostic light code for this prob-
lem is nine flashes followed by a pause. The probable
causes are either a blocked, pinched or disconnected
hose to the pressure switch, faulty pressure switch or
loose of misconnected wiring, restricted air intake or flue
piping, blocked drain system or weak induced draft
blower.
10. 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 with no further furnace operation.
The diagnostic flash code for this is a continuous flash.
The probable causes are either a short to ground in
flame sense circuit, miswiring, lingering burner flame
or a slow closing gas valve.
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