Fault Finding & Diagnosis; Fault Finding - Bosch 12/18 Instruction Manual

PROBLEM CAUSE
LOCKOUT:
Pulsation on start Combustion settings incorrect
Faulty nozzle
Intermittent lockout Bad electrical connection
Intermittent flame detection fault
Burner motor fails to Faulty motor or electrical supply
operate to motor
Control box fault
Flame detection Photocell filmed over (dirty)
fault Photocell faulty
Control box faulty
Incorrect CO Air adjustment fault
2
Oil pressure incorrect
No oil from nozzle No oil at pump
Air in pump
Nozzle blocked
Faulty pump or drive
Faulty mechanical shut off valve
(12/18 & 18/25 only)
Ignition failure Electrode settings incorrect
Faulty ignition transformer
Open circuit ignition
Faulty control box or electrical
connections not properly made
BURNER FAILS No power to boiler
TO START Faulty boiler thermostat
Programmer open circuit
Faulty control box
HIGH SMOKE Air intake/flue blocked
NUMBER Incorrect combustion settings
Oil pressure incorrect
Incorrect components used on
combustion head
Faulty nozzle
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR HEATSLAVE EXTERNAL 12/18-18/25-25/32
8 716 106 252b (07/06
REMEDY
Set up as in installation instructions
Replace nozzle
Check control box/electrical connections
See flame detection fault
Check for 230v at motor plug during
startup period
Replace control box
Wipe clean
Replace
Replace
Set up as in installation instructions
Set up as in installation instructions
Check and refill oil tank/bleed oil line
Check and clean filters & valves from oil
tank to boiler
Bleed pump
Replace nozzle
Replace
Clean or replace
Set up as in installation instructions
Replace
Check and replace electrodes or high
tension leads if necessary
Correct control box electrical
connections or replace control box
Check electrical / control circuit
Check by temporarily linking out high
limit and control thermostats
Check by temporarily linking 8 & 9 on
the connector
Replace
Check & clear air intake/flue
Set up as in installation instructions
Adjust to correct pressure
Check with installation instructions
Replace nozzle

FAULT FINDING

BOILER LOCKOUT :
Indicated by the illumination of the 'Lockout'
indicator on the fascia.
To reset, wait 2 minutes then press the lockout
reset button.
Also refer to fault finding logic on pages
46 and 47.
UNDER NO CIRCUMSTANCES MUST AN
APPLIANCE BE LEFT TO OPERATE WITH
ANY CONTOL LINKED OUT OR
OVERRIDDEN.
FAULT FINDING
44