
48
Rev. 2
SYSTEM OPERATION
ABNORMAL OPERATION
(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 for an in-
terpretation of the signals and to this section for a descrip-
tion.
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 energized
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) sec-
onds, the control will recycle this series of three tries
four (4) 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.
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 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
circulation 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 circulation blower and vent blower will be energized
all the time. The diagnostic light code for this problem is
five flashes followed by a pause. The probable 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 circulation blower and the induced draft
blower continuously. The diagnostic light code for this
problem is continuous light flashing. The probable
cause is either a short to ground in flame sense circuit
or miswiring.
LIGHT SIGNAL
FOR CORRECTIVE ACTION REFER TO
ABNORMAL OPERATION NUMBER
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
50A50 or HSI 1-1A INTEGRATED IGNITION CONTROL
DIAGNOSTIC SIGNAL CHART
LIGHT SIGNAL
FOR CORRECTIVE ACTION REFER TO
ABNORMAL OPERATION NUMBER
Continuous Light
1. Internal Control Failure
1 Flash
2. System Lockout (Retries/Recycles Exceeded)
2 Flashes
3. Pressure Switch Stuck Closed
3 Flashes
4. Pressure Switch Stuck Open
4 Flashes
5. Open Primary or Auxiliary Limit
5 Flashes
6. Open Rollout Limit
6 Flashes
7. 115V AC Power Reversed or Poor Unit Ground
8 Flashes
8. Pressure Switch Open 5 Times During Heat Cycle
9 Flashes
9. Primary Limit Open 5 Times During Heat Cycle
Continuous Flashing
10. Unanticipated Flame Present
HSI-2 INTEGRATED IGNITION CONTROL
DIAGNOSTIC SIGNAL CHART
Содержание GCIA045A30
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