Amana GUIS Installation Instructions Manual page 21

WARNING
To prevent death, personal injury or
property damage due to fire, follow these
directions for the auxiliary limit control. If
the auxiliary limit control opens, it may be
reset one time only.
SERVICER'S NOTE: If it becomes necessary to slide the
air circulation blower assembly out of the furnace, the
auxiliary limit control should be removed first. After the air
circulation blower assembly is reinstalled, the auxiliary limit
must be reinstalled.
ABNORMAL OPERATION - 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 air circulation blower access
door and make a note of the number of flashes in sequence
between pauses. Next, refer to the Diagnostic Signal Chart
for an interpretation of the signals and to this section for a
description.
1. Internal Lockout
An internal lockout occurs when the integrated ignition
control senses an internal problem and stops the unit.
The diagnostic light will indicate the condition with a
continuous light.
To solve this problem, replace the ignition control.
2. External Lockout
A external lockout occurs when the integrated ignition
control determines that a measurable combustion can-
not be established or maintained after three consecu-
tive tries (four, if flame is established then lost) to turn
on the furnace.
If a flame is not sensed during the first seven seconds
after a gas valve has been energized, the ignition
control will internally turn off the gas. After 120 seconds,
during which time the induced draft blower purges the
heat exchanger, the igniter will reenergize and preheat
for 27 seconds. The gas valve is then reenergize. If a
flame is not sensed again in seven seconds, the gas
valve will de-energize and another purge is performed.
The ignition control will cycle the gas valve three times
before it determines it cannot establish measurable
combustion and enter a lockout state. If a flame is
sensed but lost after 10 seconds, the control will cycle
four more times before locking out. A lockout stops
ignition attempts and causes the air circulation blower
to run continuously. The diagnostic light will indicate
either condition with one short flash followed by a
longer off.
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 electrical disconnect
switch to the furnace for 30 seconds. The control will
reset after two hours.
IMPORTANT: If you have to frequently reset your furnace,
it means that a problem exists that should be corrected.
Contact a qualified servicer for further information.
3. Pressure Switch Stuck Closed
A sticking pressure switch can be caused by either a
faulty pressure switch, faulty wiring, a disconnected
hose, or a restricted intake or flue piping. In the case
of a pressure switch sticking closed, the probable
cause is a faulty pressure switch or wiring.
If the ignition control senses that the pressure switch
is closed and the induced draft blower is off, it will shut
down the unit until the fault is corrected. The light code
for this problem is two short flashes followed by a
longer pause.
4. Pressure Switch Stuck Open
A sticking open pressure switch can be caused by a
faulty pressure switch, a disconnected hose to the
pressure switch, a restricted air intake or flue piping, or
faulty wiring.
If the ignition control senses that the induced draft
blower is energized but the pressure switch is not
closed, the control will keep the air circulation blower on
and wait for the switch to close. The diagnostic light
code for this problem is three short flashes followed
by a pause.
5. Open Thermal Protection Device
If the primary (high) limit, auxiliary limit, or rollout limit
control opens, the gas valve is de-energized. Both the
induced draft blower and air circulation blower are
energized on low heat speed. The diagnostic light code
for this is four short flashes followed by a longer
pause.
If the primary or auxiliary limit is open, the probable
cause is either: low conditioned air flow due to a dirty
filter or high resistance in duct work, a faulty limit, a
faulty air circulation blower or an air circulation blower
speed set too low. The primary limit will automatically
reset; however, the auxiliary limit control must be
manually reset.
If the rollout limit control is open, the probable cause is
insufficient combustion air, restricted flue passage, or
restricted heat exchanger. The rollout limit control must
be manually reset.
6. 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 circulation blower and the
induced draft blower continuously. The diagnostic light
code for this is continuous light flashing. Probable
cause is miswiring.
OPERATING INSTRUCTIONS
1. Close the manual gas valve external to the furnace.
2. Turn off the electrical power supply to the furnace.
3. Set room thermostat to lowest possible setting.
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