Honeywell 7800 SERIES Manual page 14

Fault Code
Fault 29 Lockout Interlock fault.
*Lockout ILK*
Fault 30 Running Interlock fault.
*Running ILK*
Fault 31 Low Fire Interlock Switch failure
*Low Fire Sw. Off* to close during RUN (Device
specific).
Fault 32 Combustion Airflow Interlock
*Airflow Switch* fault.
Fault 33 Pre-Ignition Interlock fault.
*Pre-Ignition ILK*
Fault 34 CTL input was energized at the
*Control On* wrong time for the relay
module. This fault implies a
field wiring error.
Table 7. Hold and Fault Message Summary. (Continued)
System Failure
19
7800 SERIES S7800A1142 KEYBOARD DISPLAY MODULE
Recommended Troubleshooting
1. Check wiring and correct any errors.
2. Inspect the fan; make sure that there is no blockage of the air
intake and that it is supplying air.
3. Make sure that the Lockout Interlock Switches are working
properly and that all switch contacts are free from
contaminants.
4. Reset and sequence the relay module to PREPURGE (place
the Run/Test Switch in the Test position, if available). Measure
the voltage between terminals 7 and L2(N). Line voltage
should be present.
5. If steps 1 through 4 are correct and the fault persists, replace
the relay module.
1. Inspect the Running Interlocks, including the Airflow Switch,
and the connections.
2. Make sure that the Running Interlocks, including the Airflow
Switch, are functioning properly and that switch contacts are
free from contaminants.
3. Reset and sequence the relay module to PREPURGE. Set the
Run/Test Switch, if available, to Test. Measure the voltage
between terminal 7 and L2(N). Line voltage should be present.
4. If steps 1 through 3 are correct and the fault persists, replace
the relay module.
1. Check wiring and correct any errors.
2. Reset and sequence the relay module.
3. Use either the manual motor position to drive the motor to the
Low Fire position, or use the Run/Test Switch option, if
available. Sequence to Run drive to Low Fire and place the
switch in the Test position. Adjust the Low Fire Switch while in
this state to make sure it is closing properly.
4. While in Run, drive to Low Fire state, measure the voltage
between terminal 18 and L2(N). Line voltage should be
present. If not, the switch adjustment is incorrect and/or the
switch is defective and needs replacement.
5. Reset and sequence the relay module. If line voltage was
present between the Low Fire Switch and terminal 18, and the
fault persists, replace the relay module.
1. Check wiring and correct any errors.
2. Inspect the fan; make sure there is no blockage of the air
intake and it is supplying air.
3. Make sure the Airflow Interlock Switches are working properly
and all switch contacts are free from contaminants.
4. Reset and sequence the relay module to PREPURGE. Place
the Run/Test Switch in the Test position, if available. Measure
the voltage between terminals 7 and L2(N). Line voltage
should be present.
5. If steps 1 through 4 are correct and the fault persists, replace
the relay module.
1. Check wiring and correct any errors.
2. Inspect the Pre-Ignition Interlock switches and make sure they
function properly.
3. Check fuel valve operation. Valve must close within five
seconds.
4. Reset and sequence the relay module.
5. During STANDBY or PREPURGE, measure the voltage
between terminal 20 and L2(N). Line voltage should be
present. If not, the Pre-Ignition Interlock switches can be
defective and need replacing.
6. If the fault persists, replace the relay module.
1. Check wiring and correct any errors.
2. Reset and sequence the relay module.
3. If fault persists, replace the relay module.
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