Honeywell 7800 Series Product Data page 25

Fault Code System Failure
Fault 57 Purge Fan Switch is off
*Purge Fan when it should be on
Sw. Off* (Fulton pulse only).
Flame is indicated
Fault 58 by both the combus-
*Combustion tion pressure and the
pressure/ flame amplifier when
Flame* it should be off (Fulton
pulse only).
Faults
59–66 *Call Unused faults.
Service*
L1 and L2 miswired/ex-
Fault 67 *AC changed (EC/RM7810,
Phase* 7820, 7830, 7850
only).
Fault 68
Pre-Ignition Interlock
*Pre-Ignition
fault.
ILK*
Fault 69–70
Unused faults.
*Call Service*
Low Fire Switch closed,
Fault 71
High Fire Switch must
*Dynamic
be open (EC/RM7850
LFS*
only).
Fault 71 Limit input (terminal 7)
*Limits Com- is off when it should be
plete* on (RM7888 only).
High Fire Switch closed;
Fault 72
Low Fire Switch must
*Dynamic
be open (EC/RM7850
HFS*
only).
Fault 72 Special Function 2 In-
*Spec. put (terminal 17) is off
Func.2* when it should be on.
Fault 73 Special Function 3 In-
*Spec. put (terminal 19) is off
Func.3* when it should be on.
Fault 74
Unused fault.
*Unused*
7800 SERIESS7800A2142 4-Line LCD Keyboard Display Module
Inspect the Prepurge Fan Switch terminal 18 and the connec-
tions.
Make sure the switch is working properly. Reset and sequence
the relay module.
If the fault persists, replace the relay module.
-
-
Check L1 and L2 for proper line phasing.
Check wiring; correct any errors.
Inspect the Pre-Ignition Interlock switches and make sure
they work
properly.
Check fuel valve operation. Valve must close within five
seconds.
Reset and sequence the relay module.
During STANDBY or PREPURGE, measure the voltage be-
tween terminal 17 and G (ground). Supply voltage should be
present. If not, the Pre-ignition Interlock switches are defec-
tive and need replacing.
If the fault persists, replace the relay module.
-
Check firing rate position switches (usually in Modutrol®
Motor) for proper operation.
Check wiring, correct any errors.
Reset and sequence the relay module.
If the fault persists, replace the relay module
Check limits to make sure they are satisfied after resetting.
Check electrical connections to terminal 7 of wiring subbase.
Reset relay module.
If the fault persists, replace the relay module.
Check firing rate position switches (usually in Modutrol®
Motor) for proper operation.
Check wiring, correct any errors.
Reset and sequence the relay module.
If the fault persists, replace the relay module.
Check operation of Special Function 2 of PLC.
Check electrical connection to terminal 17 of wiring subbase
and confirm presence of supply power when Special Function
2 is activated.
Reset relay module.
If the fault persists, replace the relay module.
Check operation of Special Function 3 of PLC.
Check electrical connection to terminal 19 of wiring subbase
and confirm presence of supply power when Special Function
3 is activated.
Reset relay module.
If the fault persists, replace the relay module
-
25 32-00110-07