Honeywell 7800 Series Product Data page 21

Fault Code
Fault 51 Flame signal value is too high
*Flame Too Strong* to be valid.
Fault 52 Pilot Valve 2 (terminal 21) was
*Call Service* off when it should be on.
Fault 53 Lockout Input fault
*Lockout Switch* (EC/RM7850 only).
Fault 54 Combustion pressure switch
*Comb. Pressure* fault (Fulton pulse only).
Fault 55 Purge fan switch is on when it
*Purge Fan Sw. On* should be off (Fulton pulse
only).
Fault 56 Block intake fault (Fulton pulse
*Block Intake* only).
Fault 57 Purge Fan Switch is off when it
*Purge Fan Sw. Off* should be on (Fulton pulse
only).
FAult 58 - 66 Unused faults.
*Call Service*
Fault 67 L1 and L2
*AC Phase* miswired/exchanged
(EC/RM7850 only).
Table 7. Hold and Fault Message Summary (Continued).
System Failure
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21
7800 SERIES S7800A KEYBOARD DISPLAY MODULE
Recommended Troubleshooting
1. Make sure that flame detector and flame amplifier are
compatible.
2. Remove the flame amplifier and inspect the connections.
Reset the flame amplifier.
3. Reset and sequence the relay module.
4. Check the flame detector sighting position, reset and cycle.
5. Verify that no ignition noise is present in the F lead due to wire
routing.
6. Measure the flame strength. Verify it meets specifications. If
not, refer the flame amplifier and/or flame detector checkout
procedures.
7. If the code reappears, replace the flame amplifier.
8. If the code reappears, replace the flame detector.
9. If the fault persists, replace the relay module.
1. Inspect terminal 21 and connections. Make sure that the valve
is operating properly.
2. Reset and sequence the relay module.
3. If the fault persists, replace the relay module.
1. Check wiring and correct any errors.
2. Inspect the Lockout Switch to make sure it is working properly.
3. Reset and sequence the relay module. During STANDBY or
PREPURGE, measure the voltage between terminal 20 and
L2(N). Supply voltage should be present. If not, the lockout
switch is defective and needs replacing.
4. If the fault persists, replace the relay module.
1. Check wiring and correct any errors.
2. Inspect the Combustion Pressure Switch to make sure it is
working correctly.
3. Reset and sequence the relay module.
4. During STANDBY and PREPURGE, measure the voltage
between terminal 20 and L2(N). Supply voltage should be
present. If not, the Combustion Pressure Switch is defective
and needs replacing.
5. If the fault persists, replace the relay module.
1. Check wiring and correct any errors.
2. Inspect the Purge Fan Switch terminal 18 and its connections.
Make sure the switch is working correctly and is not jumpered
or welded.
3. Reset and sequence the relay module.
4. If the fault persists, replace the relay module.
1. Check wiring and correct any errors.
2. Inspect the Block Intake Switch and make sure it is working
properly.
3. Reset and sequence the relay module.
4. During PREPURGE, measure the voltage between terminal 7
and L2(N). Supply voltage should be present. If not, the Block
Intake Switch is defective and needs replacing.
5. If the fault persists, replace the relay module.
1. Inspect the Prepurge Fan Switch terminal 18 and the
connections. Make sure the fan is working properly.
2. Reset and sequence the relay module.
3. If the fault persists, replace the relay module.
1. Check L1 and L2 for proper line phasing.
65-0090—4