Boiler pressure problem

[Byelobog]

Hi All,

Hopefully someone can assist with this query please.

I have a Vaillant Eco Plus 831 combi which was installed in 2008 (fitted with a time switch & Drayton wireless RF). We have never had a problem with the boiler and everything works as expected, but I am worried about the pressure being too high when the central heating is on and it causing some long term issue.

We have 10 rads being fed and they all get to a good temperature. I noticed that the pressure had got to 3.2 BAR (red zone) a few weeks ago and the boiler display flashes with the value maybe indicating a problem. At the time I opened a valve out side the house to drain the rads which brought the pressure down to about 2.0 (grey zone) when the heating was on.

I just checked again and the BAR pressure was back up to 3.2 again after about 2-3 weeks when the heating was on even though I have not added any more pressure via the valve under the boiler.

Can someone please advise what would make the pressure increase so much, and if it really is a problem ?

If so, I'll get a professional in to take a look.

Any feedback would be really appreciated !!

 

[Howsie]

Hello. Sounds like the filling 'loop' is passing. Is it fully off? If so, call your installer back to resolve.

 

[steadyon]

If the pressure rises when the heating is on, but then reduces as the system gets cold, then it is likely to be the expansion vessel having lost its charge or become faulty.

If the pressure does not fall when the boiler has been off for a while then it will be mains water getting into the system. Either from the filling loop as outlined in post 2 above, or possibly but less likely from a defective hot water heat exchanger.

It is a problem, and you should get a professional in.

 

[Howsie]

If the pressure rises when the heating is on, but then reduces as the system gets cold, then it is likely to be the expansion vessel having lost its charge or become faulty.

If the pressure does not fall when the boiler has been off for a while then it will be mains water getting into the system. Either from the filling loop as outlined in post 2 above, or possibly but less likely from a defective hot water heat exchanger.

It is a problem, and you should get a professional in.

The OP seems to have drained the system to reduce the pressure yet it still rises my money is on the loop.

 

[Centralheatking]

Have you got an internal filling loop on this model or
is it the external braided one - detach external one and check internal loop is off.

CHK

 

[Ermintrude]

Only happens when heating on and droops back when cold.... Couldn't be zilmet friends again? Get a GSR in for a service and a look at it. He should see fault from the doorstep.