Fault Finding - Bosch External System 12/18 Users Instructions And Customer Care Manual

2.2.6 Fault finding

Problem
Desired room temperature is
not reached
Desired room temperature
exceeded by large amount
Temperature rises instead of
falling
No Programmer display or
Programmer does not
respond
Hot water temperature too
low
Danesmoor External & External System– 6 720 809 792 (2013/10)
Cause
Thermostatic radiator valve(s) set too low
Room temperature set too low
Temperature control on the boiler set too low
Air is trapped in the heating system
Radiators are too hot
Clock/programmer is incorrectly set
Momentary power failure
Hot water temperature set too low
Cylinder is cold
Remedy
Increase thermostatic radiator valve setting(s)
Increase room temperature setting
Increase temperature control setting
Bleed radiators and recharge heating system
Turn down thermostatic radiator valves/room
thermostat/boiler temperature control setting
Check the setting
Switch off the boiler at the master switch, wait a
few seconds and then switch the boiler on again
Check the setting of the cylinder thermostat, then
the boiler temperature control setting
Check programmer timings
Using your boiler
7