E
Troubleshooting
34
NEPTUNE 5 FA_EN_Ver.2.0_25/11
ERROR CODE CHECK LIST
Display
Symptom
Outer cause
Inner cause
Check
HOS
Hot Safety temperature
switch B3 opens when
temp is higher than 270
deg C (518 deg F).
Wire defective.
Flow and pressure
switch out of ad-
justment. Oil resi-
due in boiler. Boi-
ler clogged up.
Boiler security
adjustment.
Switch B3 must
be changed IF
open.
POL
Pump Oil Low
Switch B6 open.
Wire defective. Oil seals worn out. B6 Switch.
LHL
Light sensor B7 see Light,
when Y1 is not activated
Flame sensor short circuit
(Cold water operation, not
possible).
Sensor not in
place.
Wire defective.
Oil residue in boi-
ler is burning.
Y1 Leaky.
Egnition failure.
Oil pressure.
Nozzle
Electrode
Flame sensor.
HOP
Hot Motor Protector
Motor winding >160degC
(320degF).
Pump pressure
too high.
Temp in room
>40degC
(104degF).
Fan on motor de-
fective.
Fuse(F1 2amp).
Sensor in win-
dings.
FLF
Flow Failure
Flow switch B2 closed and
B4 open.
Wire defective
Flow piston han-
ging.
Reed switch.
LHE
No Light, Fuel Enabled.
Light sensor B7 see no
light when Y1 is open.
Wire defective.
Spark failure.
Oil filter blocked
soot on glass.
Flow switch off.
Fuse (F11).
Sensor B7.
FUE
Fuel Empty.
Levelswitch B9 Open.
Wire defective.
B9 switch
LEA
Leakage.
Three times start without
flow.
Leaky system.
Leaky non-return
valve.
B4 switch.
UPC
U-processor failure.
Water in electric
system.
SEO
Temperature Sensor
Open.
Wire defective.
B1 switch
SEC
Temperature Sensor Clo-
sed.
Wire defective.
B1 switch
FLO
Flow switch B2open and
flow switch B4 close.
Air in suction
water.
No water.
Detergent valve.
Summary of Contents for NEPTUNE 5 FA
Page 1: ...Service Manual NEPTUNE 5 FA NEPTUNE 5 FA_EN_Ver 2 0_25 11 ...
Page 54: ...H Wiring diagrams NEPTUNE 5 FA_EN_Ver 2 0_25 11 54 ...
Page 55: ...H Wiring diagrams NEPTUNE 5 FA_EN_Ver 2 0_25 11 55 ...
Page 56: ...H Wiring diagrams NEPTUNE 5 FA_EN_Ver 2 0_25 11 56 ...
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