I have read a lot of your usefull advice on heating and specially on Vaillant boilers and was hoping that you may be able help me.
When CH is switched on boiler fires and run for 25 mts to get the temperature to 80. On reaching 80 flame goes off and comes back when the teperature has fallen to about 50. This will go on without a problem if no DHW is drawn. Fine.
Once DHW is drawn & taps closed ; on returning to CH the flame goes off on reaching a temperaturte of about 70 and does not come back untill the temperature has dropped to 40 or below and will continue to work between 40 and 70 degrees
How can I rectify this.
The system would not fire at all after the cold spell, not having been used for about ten days. Rads were taken out and flushed, diverter valve assembly cleaned and boiler flushed. Pump flushed and impeller cleaned and fitted. gas sound. The DHW flow rate incresed but heigher temperature can be achieved by contrlling the flow at the taps.
(however still top of rads feel little warmer than the bottom)
Many Thanks
Don
When CH is switched on boiler fires and run for 25 mts to get the temperature to 80. On reaching 80 flame goes off and comes back when the teperature has fallen to about 50. This will go on without a problem if no DHW is drawn. Fine.
Once DHW is drawn & taps closed ; on returning to CH the flame goes off on reaching a temperaturte of about 70 and does not come back untill the temperature has dropped to 40 or below and will continue to work between 40 and 70 degrees
How can I rectify this.
The system would not fire at all after the cold spell, not having been used for about ten days. Rads were taken out and flushed, diverter valve assembly cleaned and boiler flushed. Pump flushed and impeller cleaned and fitted. gas sound. The DHW flow rate incresed but heigher temperature can be achieved by contrlling the flow at the taps.
(however still top of rads feel little warmer than the bottom)
Many Thanks
Don