Powermax HE85i presssure loss....

[kelvyn29]

Hi,
Wondering if anyone can help....

We bought our NEW build 5 & half years ago that had a Poterton Powermax HE85i combi boiler.

Everything has been ok, but recently has been locking out.

After doing a bit of a search round I discovered the PRV was dripping all the time, So I bought a new 1 and replaced.

But still havin issues The bolier seems steady with the hot water on, but the minute you turn on the heating after about 20mins or so the system pressure raises to 3 opening the PRV & letting the pressure out.

Once the system cools down the pressure then drops & then locks out.

I have checked the cannister thing & the pressure in here is 1.1bar

Any ideas what it could be??

Thanks

Kelvyn

 

[45yearsagasman]

The flexible braided hose that connects to the "cannister thing" (expansion vessel) may be blocked.
The only way is to de pressurise the system and remove the exp vessel and hose to check.

 

[kelvyn29]

The flexible braided hose that connects to the "cannister thing" (expansion vessel) may be blocked.
The only way is to de pressurise the system and remove the exp vessel and hose to check.

Ok thanks I will have a look.

The braided hose its self has been squashed & I did re straighten it out

 

[andytw]

I have checked the cannister thing & the pressure in here is 1.1bar

The expansion vessel has 2 sides to it, a water side and an air side.
You have measured the pressure in the air side at 1.1 bar but did you do this with NO pressure on the water side. To achieve this you need to release pressure in the heating system via a radiator vent or similar. Opening the pressure relief valve to do this is frowned on as once opened they tend to not re-seal.

I did one for a neighbour yesterday, removed the expansion vessel from the boiler, fitted a new schraeder valve, re-inflated to 1 bar and re-installed it in the boiler.

andytw