In the unlikely event the boiler does not give complete
satisfaction, before calling for a Service Engineer, the
Installer should check the following:-
General checks
▶ Is the mode switch in boiler/ON mode?
▶ Is there 230V across the boiler live and neutral terminals?
▶ Is there 230V across the terminals 1 and N? If not there is no demand to the
boiler from the controls or the control wiring is not correct.
▶ Is the polarity correct? (230V across live and earth, 0V across neutral and earth)
▶ Is the air bled from the primary system?
▶ Is the air bled from the oil supply?
▶ Is the flue sized and routed correctly?
Boiler runs straight to lockout
▶ Has the oil line been purged of air?
▶ Where an air eliminator is used in conjunction with a top feed oil tank the non-
return valve, (if fitted), should be removed from the oil dip pipe.
No domestic hot water
▶ Is there a domestic hot water demand from the programmer and has the tank
reached temperature?
▶ Is the circulating pump operating?
▶ Are the programmer, tank thermostat, circulating pump and diverter valve/zone
valves wired correctly?
▶ Is there 230V across 1 and N? If not there is no demand to the boiler from the
controls or the controls wiring is not correct.
No central heating
▶ Are both programmer and room thermostat on demand for central heating?
▶ Are the room thermostat, programmer, circulating pump and diverter valve/zone
valves (if CH and DHW system) wired correctly?
▶ Is the circulating pump operating?
▶ Is there 230V across 1 and N? If not there is no demand to the boiler from the
controls or the controls wiring is not correct.
Worcester, Bosch Group
Cotswold Way, Warndon, Worcester WR4 9SW.
Tel. 0330 123 9559
Worcester, Bosch Group is a brand name of Bosch Thermotechnology Ltd.
worcester-bosch.co.uk
6 720 821725 (2018/04)
WORCESTER, BOSCH GROUP:
TECHNICAL SUPPORT:
0330 123 3366
APPOINTMENTS:
0330 123 9339
SPARES:
0330 123 9779
LITERATURE:
0330 123 9119
TRAINING:
0330 123 0166
SALES:
0330 123 9669