Dear all
Our Vaillant VCW BG 221 H BF boiler is 15 years old and has been working perfect until recently. The Domestic Hot Water (DHW) is still working o.k but the Central Heating (CH) is very temperamental.
When there is a call for central heating is made the boiler fires o.k in the first instance until the CH temperature reaches the presetting level via the CH thermostat, then the flame of the main burner goes off (the pilot stays on) as expected. At this stage, it carries on working sometimes as long as the there is a demand for CH, and it stops other times, i.e the boiler does not fire despite the fact that we can hear the pump running.
When it gets into this mode we always cancel the demand for CH and recall it again straight away the boiler fires up as normal.
The boiler fires at all time when there is a demand for DHW.
Any idea please
Many thanks
Our Vaillant VCW BG 221 H BF boiler is 15 years old and has been working perfect until recently. The Domestic Hot Water (DHW) is still working o.k but the Central Heating (CH) is very temperamental.
When there is a call for central heating is made the boiler fires o.k in the first instance until the CH temperature reaches the presetting level via the CH thermostat, then the flame of the main burner goes off (the pilot stays on) as expected. At this stage, it carries on working sometimes as long as the there is a demand for CH, and it stops other times, i.e the boiler does not fire despite the fact that we can hear the pump running.
When it gets into this mode we always cancel the demand for CH and recall it again straight away the boiler fires up as normal.
The boiler fires at all time when there is a demand for DHW.
Any idea please
Many thanks
