Submittal Sheet

7800 SERIES S7800A2142 KEYBOARD DISPLAY MODULE
21 32-00110—05
Fault 26
*Man-Open Sw. Off*
The Manual Open Valve
Switch was off when it should
be on (Device specific).
1. Check wiring and correct any errors.
2. Make sure that the Manual Open Valve Switch is fully open.
3. Make sure that the Manual Open Valve Switch is
functioning properly and that the switch contacts are free
from contaminants.
4. Reset and sequence the relay module.
5. Make sure that the Manual Open Valve Switch provides an
electrical path when closed. Verify that the relay module is
receiving power at terminal 17.
6. If steps 1 through 5 are correct and the fault persists,
replace the relay module.
Fault 27
*Start Switch On*
Start Switch was on during
PREPURGE (Device specific).
1. Start Switch held on too long.
2. Check wiring; verify that Start Switch is correctly con-
nected.
3. Make sure that the Start Switch is functioning properly and
that the switch contacts are free of contaminants.
4. Reset and sequence the relay module to PREPURGE; set
the Run/Test Switch to Test. Make sure there is no power at
terminal 6 during PREPURGE.
5. If steps 1 through 4 are correct and the fault persists,
replace the relay module.
Fault 28
*Pilot Flame Fail*
Pilot flame failure. 1. Check pilot valve wiring and operation. Correct any errors.
2. Check fuel supply.
3. Check pilot pressure and repeat pilot turndown test.
4. Check ignition transformer electrode, flame detector, flame
detector sighting and flame amplifier.
5. If steps 1 through 4 are correct and the fault persists,
replace the relay module.
Fault 29
*Lockout ILK*
Lockout Interlock fault. 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). Mea-
sure the voltage between terminals 7 and L2(N). Line volt-
age should be present.
5. If steps 1 through 4 are correct and the fault persists,
replace the relay module.
Fault 30
*Running ILK*
Running Interlock fault. 1. Inspect the Running Interlocks, including the Airflow
Switch, and the connections.
2. Make sure that the Running Interlocks, including the Air-
flow Switch, are functioning properly and that switch con-
tacts are free from contaminants.
3. Reset and sequence the relay module to PREPURGE. Set
the Run/Test Switch, if available, to Test. Measure the volt-
age 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.
Table 5. Fault Message Summary. (Continued)
Fault Code System Failure Recommended Troubleshooting