Kenmore N8MSL0701412A1 Installation Instructions Manual page 46

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2 PRESSURE SWITCH DID NOT OPEN -
Check for:
- Obstructed pressure tube.
- Pressure switch stuck closed.
3 PRESSURE SWITCH DID NOT CLOSE
OR REOPENED If opens during blower
on-delay period, blower will come on for
the selected blower off-delay. If open
longer than 5 minutes inducer shuts off for
15 minutes before retry. Check for:
- Proper vent sizing.
- Low inlet gas pressure (if LGPS used).
- Inadequate combustion air supply.
- Disconnected or obstructed pressure
tubing.
- Defective or miswired pressure switches
- Excessive wind.
- Restricted vent.
- Defective Inducer motor.
- Low inducer voltage (115 VAC)
LIMIT CIRCUIT FAULT - Indicates the
limit, draft safeguard, flame rollout, or
blocked vent switch (if used) is open.
Blower will run for 4 min. or until open
switch remakes whichever is longer. If
open longer than 3 min, code changes to
lockout #7. If open less than 3 rain. status
code #4 continues to flash until blower
shuts off. Flame rollout and blocked vent
switch require manual reset. Check for:
- Restricted vent.
- Loose blower wheel.
- Defective switch or connections.
- Proper vent sizing.
- Dirty filter or restricted duct system.
- Excessive wind.
- Inadequate combustion air supply.
(Flame rollout switch open)
- Defective blower motor
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ABNORMAL FLAME-PROVING SIGNAL
Flame is proved while gas valve is de-
energized. Inducer will run until fault is
cleared. Check for:
- Stuck open or leaky gas valve.
IGNITION PROVING FAILURE -If flame is
not sensed during the trial for ignition
period, the control will repeat the ignition
sequence 3 more times before lockout #6 +
1 occurs. If flame signal is lost during the
blower on-delay period, blower will come on
for the selected blower off-delay. Check
the following before going to the next step.
- Gas valve electric switch on?
- Manual shut-offvalve open?
- Green/Yellow wire MUST be connected
to furnace sheet metal.
- Flame sensor must not be grounded.
LIMIT CIRCUIT LOCKOUT - Lockout
occurs if the limit, draft safeguard, flame
rollout, or blocked vent switch (if used) is
open longer than 3 minutes. Control will
auto-reset after 3 hours. Refer to status
code #4.
GAS HEATING LOCKOUT - Control will
NOT auto reset. Turn off power and wait
5 minutes to retry. Check for:
- Stuck closed gas valve relay on control.
- Miswire or short to gas valve wire.
POLARITY - Check for correct line
voltage polarity. If units are twinned,
check for proper low--voltage (24V)
transformer phasing.
1 + 2 BLOWER ON AFTER POWER UP
(115V OR 24V) Normal operation.
Blower runs for 90 seconds, if unit is
powered up during a call for heat (R-
W/W1 closed) or when (R--W/W1 opens)
during the blower on--delay period.
6 + 1 IGNITION LOCKOUT - System failed to
ignite gas and prove flame in 4
attempts. Control will auto-reset after 3
hours. Refer to status code #6.
To determine whether the problem is in the gas
valve, igniter, or flame sensor the system can be
operated in component test mode. To check the
igniter, remove the R thermostat connection
from the control, reset power, start the
component test. Does the igniter glow
orange/white by the end of the 15 second warm-
up period?
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NOTE:
NUMBER IN UPPER LEFT HAND
CORNER REPRESENTS FLASH CODE
Unplug igniter harness from control and
repeat component test. Check for 115V
between connector P2 (HSI) and
NEUTRAL4_2 on the control. Was 115V
present for the 15 second period?
Reconnect the R thermostat lead and set
thermostat to call for heat. Connect
voltmeter across gas valve connections.
Does gas valve receive 24V?
YES
Does gas valve open and allow gas to
flow?
YES
Do the main burners ignite?
YES
Do the main burners stay on?
Repeat call for heat and check flame
sensor current during trial for ignition
period. Is the DC current below 0.5 ,uA?
_ YES
Clean flame sensor with fine steel wool
and recheck current. Nominal current is
4.0 to 6.0 #A DC.
Is current near typical value?
YES
Will main burners ignite and stay on?
YES
Fixed.
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Replace furnace control.
Check fer continuity in the
harness and igniter. Replace
defective component.
Check connections. If OK,
replace control.
Check that gas valve electric
switch is turned on. Replace
valve.
Check fer:
- Inadequate flame carryover
or rough ignition.
- Low inlet gas pressure.
- Proper firing rate.
- Air leakage around igniter
bracket.
Allow blower to come on and
repeat test to check for
intermittent operation.
Check connections and retry.
If current is near typical value
(4.0-6.0_ DC nominal) and
burners will not stay on,
replace control.
Replace electrode.
Replace furnace control.
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