Instruction manual

FAULT FINDING
WORCESTER BOSCH GREENSTAR 12i & 24i SYSTEM
8 716 115 171a (06/2008)
10
FAULT FINDING
Problem Cause Remedy
Switch off boiler at mains
power switch, wait a few
seconds then switch on
again
Check setting
Adjust cylinder thermostat
Desired room
temperature is not
reached
Thermostatic radiator
valve(s)/ room thermostat
set too low
Temperature control for
CH flow on boiler set too
low
Air trapped in heating
system
Desired room
temperature exceeded by
large amount
Heating stays on for too
long
No on/off indicator light
Hot water temperature
too low
Radiators are too hot
Programmer is
incorrectly set
Momentary power failure
Programmer setting
Cylinder thermostat set too
low
Adjust cylinder thermostat
Hot water temperature
too high
Cylinder thermostat set too
high
Increase thermostatic
radiator valve setting(s)/
room thermostat
Increase CH flow
temperature control
setting
Bleed radiators and
recharge heating system
Turn down thermostatic
radiator valves / room
thermostat
Reduce temperature on
boiler (This may affect the
temperature of the hot
water cylinder)
Check setting
This table gives information on basic operating system problems.
In the unlikely event of a boiler fault please read the following page thoroughly
before contacting Worcester, Bosch Group.
MAINTENANCE