Bosch 12/18 User Manual
PROBLEM
CAUSE
REMEDY
LOCKOUT:
Pulsation on start
Combustion settings incorrect
Set up as in installation instructions
Faulty nozzle
Replace nozzle
Intermittent lockout
Bad electrical connection
Check control box/electrical connections
Intermittent flame detection fault
See flame detection fault
Burner motor fails to
operate
operate
Faulty motor or electrical supply
to motor
to motor
Check for 230v at motor plug during
startup period
startup period
Control box fault
Replace control box
Flame detection
Photocell filmed over (dirty)
Wipe clean
fault
Photocell faulty
Replace
Control box faulty
Replace
Incorrect CO
2
Air adjustment fault
Set up as in installation instructions
Oil pressure incorrect
Set up as in installation instructions
No oil from nozzle
No oil at pump
Check and refill oil tank/bleed oil line
Check and clean filters & valves from oil
tank to boiler
tank to boiler
Air in pump
Bleed pump
Nozzle blocked
Replace nozzle
Faulty pump or drive
Replace
Faulty mechanical shut off valve
Clean or replace
(12/18 & 18/25 only)
Ignition failure
Electrode settings incorrect
Set up as in installation instructions
Faulty ignition transformer
Replace
Open circuit ignition
Check and replace electrodes or high
tension leads if necessary
tension leads if necessary
Faulty control box or electrical
connections not properly made
connections not properly made
Correct control box electrical
connections or replace control box
connections or replace control box
BURNER FAILS
No power to boiler
Check electrical / control circuit
TO START
Faulty boiler thermostat
Check by temporarily linking out high
limit and control thermostats
limit and control thermostats
Programmer open circuit
Check by temporarily linking 8 & 9 on
the connector
the connector
Faulty control box
Replace
HIGH SMOKE
Air intake/flue blocked
Check & clear air intake/flue
NUMBER
Incorrect combustion settings
Set up as in installation instructions
Oil pressure incorrect
Adjust to correct pressure
Incorrect components used on
combustion head
combustion head
Check with installation instructions
Faulty nozzle
Replace nozzle
FAULT FINDING
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR HEATSLAVE EXTERNAL 12/18-18/25-25/32
8 716 106 252b (07/06
8 716 106 252b (07/06
44
FA
U
LT
F
IN
D
IN
G
& D
IA
G
R
A
M
S
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.
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.
46 and 47.
UNDER NO CIRCUMSTANCES MUST AN
APPLIANCE BE LEFT TO OPERATE WITH
ANY CONTOL LINKED OUT OR
OVERRIDDEN.
APPLIANCE BE LEFT TO OPERATE WITH
ANY CONTOL LINKED OUT OR
OVERRIDDEN.