Vaillant pressure problem, new boiler

[mylifestory]

Hi there,
Ive got a Vaillant boiler with megaflow tank, 18 months old, from new the pressure drops so it cuts out, every few months, now twice in past month. Vaillant have said there's nothing wrong with it. A week later it does it again.

Any ideas?

Thanks!

 

[Rtplumb]

Hi there,
Ive got a Vaillant boiler with megaflow tank, 18 months old, from new the pressure drops so it cuts out, every few months, now twice in past month. Vaillant have said there's nothing wrong with it. A week later it does it again.

Any ideas?

Thanks!

Just a suggestion. If there are no obvious leaks on the whole system try checking the boiler's PRV (pressure release valve) to see if it's passing when the boiler gets up to temperature.

 

[Plumbbob1]

Just a suggestion. If there are no obvious leaks on the whole system try checking the boiler's PRV (pressure release valve) to see if it's passing when the boiler gets up to temperature.

Hi there,
Ive got a Vaillant boiler with megaflow tank, 18 months old, from new the pressure drops so it cuts out, every few months, now twice in past month. Vaillant have said there's nothing wrong with it. A week later it does it again.

Any ideas?

Thanks!

 

[Last Plumber]

The water is escaping somewhere. Vaillant will have isolated the boiler presumably, to eliminate that side. I would think they checked the PRV and heat ex for leaks.
More often than not it is on the system. Obvious places are radiator valves. Do you have suspended floors? It could be below those if you do.