15
FAULT FINDING
6 720 644 864a (2010/10)
7FAULT FINDING
If a boiler fault occurs, please read the following page thoroughly before contacting Worcester, Bosch
Group.
Problem Cause Remedy
Desired room temperature is
not reached
Thermostatic radiator valve(s)
set too low
B Increase thermostatic
radiator valve setting(s)
Temperature control for
central heating flow on boiler
set too low
B Increase central heating
flow temperature control
setting
Air trapped in heating system
B Bleed radiators and
recharge heating system
Desired room temperature
exceeded by large amount
Radiators are too hot B Turn down thermostatic
radiator valves/room
thermostat
B Reduce central heating
temperature by turning
down the Central Heating
control on boiler
Heating stays on for too long Clock is incorrectly set B Check setting and adjust
No ON/OFF mains indicator Momentary power failure B Switch off boiler at master
switch, wait a few seconds
then switch on again
Hot water temperature too
low
Temperature set too low B Check setting and adjust
Hot water temperature too
high
Temperature set too high B Check setting and adjust
Tab. 2