2nd Ave. Honeywell Relay Modules 7800 Series User Manual
Page 12
12
7800 SERIES RELAY MODULES
65-0229—1
Table 3. Hold and Fault Message Summary (continued).
Fault Code
System Failure
Recommended Troubleshooting
Fault 18
*Flame Detected*
Flame sensed when shutter is
open and no flame is expected
during PREPURGE.
1.
Check that flame is not present in the combustion chamber.
Correct any errors.
2.
Make sure that the flame amplifier and flame detector are
compatible.
3.
Check the wiring and correct any errors. Make sure F and G
wires are in individual conduits and protected from stray
noise pickup.
4.
Remove the flame amplifier and inspect the connectors.
Reseat the flame amplifier.
5.
Reset and sequence the relay module.
6.
If the code reappears, replace the flame amplifier and/or the
flame detector.
7.
If the fault persists, replace the relay module.
Fault 19
*Main Flame Ign.*
Flame was lost during MFEP or
the first 10 seconds of the RUN
state.
1.
Inspect the main fuel valve(s) and connection(s).
2.
Make sure that the fuel pressure is high enough to supply
fuel to the combustion chamber.
3.
Make sure the flame detector is positioned to obtain the
required flame signal strength; reset and recycle.
Fault 20
*Low Fire Sw. Off*
Low Fire Interlock switch failure
to close during PREPURGE.
1.
Check wiring and correct any errors.
2.
Reset and sequence the relay module.
3.
Use either the manual motor potentiometer to drive the
motor to the Low Fire position or use the Run/Test Switch
option, if available. Sequence to Prepurge drive to Low Fire
and place in the Test position. Adjust the Low Fire Switch
to make sure that it closes properly.
4.
Measure the voltage between terminal 18 and G (ground)
while in the Prepurge drive to Low Fire state. Line supply
voltage should be present. If not, the switch adjustment is
incorrect and/or the switch is defective and needs
replacing.
5.
Reset and sequence the relay module. If line supply voltage
was present between the Low Fire Switch and terminal 18,
and the fault still persists, replace the relay module.
Fault 21
*Running ILK*
Running Interlock fault during
PREPURGE.
1.
Check wiring; correct any errors.
2.
Inspect the fan; make sure there is no blockage of the air
intake and that it is supplying air.
3.
Make sure the Interlock Switches are working properly and
that all switch contacts are free of contaminants.
Fault 22
*Lockout ILK*
Lockout Interlock fault during
PREPURGE.
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 G (ground).
Line voltage should be present.
Fault 23
*Airflow Switch*
Combustion airflow interlock
fault during PREPURGE.
5.
If steps 1 through 4 are correct and the fault persists,
replace the relay module.
Fault 24
*Call Service*
The flame interlock (relay
module) was on when it should
be off.
1.
Check for F leadwire routing. Make sure routing is in its
conduit and isolated from noise-producing circuits.
Fault 25
*Call Service*
The flame interlock (relay
module) was off when it should
be on.
Fault 26
*Man-Open Sw. Off*
The Manual Open Valve Switch
was off when it should be on
(RM7838B only).
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.
(continued)