Boiler keeps re-starting

[Akshay]

Hi, we had the water supply turned off at the mains recently to replace 2 radiators, but now there seems to be a problem with our Vailiant TurboMax combi boiler. Whenever the hot water tap is released the boiler fires up but after a short while you can hear it switch off momentarily before firing up again. The result is only lukewarm water because the boiler is never on constantly enough for the water to get hot.

I've checked all radiators for any air in the system.

Any ideas what the problem could be?

 

[EliteHeat]

Does it work OK on central heating?

 

[Akshay]

Hi, no it does the same thing with the central heating too!

 

[EliteHeat]

Could be a few things. A likely cause would be a defective fan or air pressure switch. Either way you will need a registered installer to check it as neither is the province of a DIYer.