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If the control senses an open pressure switch during the pre-purge cycle, the induced draft blower only will be energized. If the
pressure switch opens after ignition has begun the gas valve is de-energized, the circulator blower heat off cycle begins, and the
induced draft blower remains on. The diagnostic LED (red) code is two (2) flashes.
P
S
S
RESSURE
WITCH
TUCK
A stuck closed pressure switch can be caused by a faulty pressure switch or faulty wiring. If the control encounters a pressure
switch stuck closed, the induced draft blower remains off. The diagnostic red LED code for this fault is three (3) flashes.
P
L
RIMARY
IMIT
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 until the limit switch re-closes. The diagnostic LED (red) code for an
open limit is four (4) flashes.
NOTE: If the primary limit opens five (5) 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. The diagnostic LED (red) code for this condition is seven (7) flashes.
F
D
G
LAME
ETECTED WITH
If flame is detected with the gas valve de-energized, the combustion and air circulator blowers are energized. The diagnostic fault
code is five (5) flashes (red LED) for this condition. The flame diagnostic LED (amber) will flash (2) times to indicate this condition.
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.
L
F
S
OW
LAME
IGNAL
Under some conditions, the fuel or air supply can create a nearly invisible coating on the flame sensor. This coating acts as an
insulator 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.
A
O
- C
BNORMAL
PERATION
S
C
C
HORT
YCLE
OMPRESSOR
The automatic ignition control has a built-in feature that prevents damage to the compressor in short cycling situations. In the
event of intermittent power losses or intermittent thermostat operation, the ignition control 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). The diagnostic red LED will flash six (6) times to indicate the compressor contactor output is being delayed.
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.
H
P
S
/L
IGH
RESSURE
WITCH
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. If either devices opens, the diagnostic red LED will flash (9) times to indicate that a refrigeration system pressure
switch is open.
C
LOSED
V
C
AS
ALVE
LOSED
OOLING
D
ELAY
C
S
OSS OF
HARGE
WITCH
18
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