Powermax 155x high pressure problem

[jamineke]

i have recently moved into a second floor flat and have a problem with my Powermax 155x boiler.
when the program clicks on (in timed mode) it seems to work fine but the pressure gauge rises to approximately 2bar before allowing any water to circulate around the radiators (after about 5-8minutes); it then continues to rise up to 3 bar(within10-15minutes of coming on) at which point i panic and turn the whole lot off, as it says to do so in the instructions.
this has only happened since i refilled the system, after the pressure dropped to zero and the lock-out light came on. When this happened i re-filled the system as instructed to do by an engineer (which i called out at great expense the first time it dropped to zero
i have both the user's instructions and the installation & servicing instructions and having read both i am still clueless.
please can anyone help?
i really don't want to have to call out an engineer if it is something straight forward (as i really cannot afford it )
Thanks in anticipation!

 

[jamineke]

some further information if needed..........
its a Range Powermax (Division of RSA Water heating Ltd) (who no longer exist i think)

All radiators have been bled and work fine!

I'm a total novice when it comes to these horrid combi boilers but the installation instructions have quite a good diagram (fig 12.2) that annotates all main parts so i should be able to follow most of the technical jargon.

Thanks!

 

[Gasguru]

You have a thermal store type of system. (Now part of Baxi group)

The unit houses a large vessel of water that is heated to around 82 degrees. Once this has reached about 60 degrees the pump will operate and heat the radiators.

It appears the expansion vessel is either flat or contains very little air. Hence the initial rise to 2 bar as the store is heated and a further rise as the radiators are heated.
I assume you are only presurising to about 1 Bar.

You need to reduce the system pressure down to zero, check the expansion vessel pre-charge is about 0.8 bar and re-presurise. Check the safety valve isn't dripping as you have had the pressure close to its opening setting of 3 bar.

 

[jamineke]

Thanks !

by expansion vessel do you mean the blue DHW expansion Vessel? or is there another one somewhere?

Will try as soon as the pressure drops all the way to zero.

Thanks again

 

[HarrogateGas]

Not on Coppice are you?

 

[jamineke]

if by coppice you mean coppice gardens in harrogate then no, i'm from northallerton.

if by coppice your on about some plumbing term then i don't know!

sorry i'm a simpleton i know!LOL

 

[Gasguru]

No not the blue domestic expansion vessel. That's probably flat as well but leave that for now.

You have to manually reduce the pressure to zero - preferably off a drain off valve or radiator tail.

There should be a red vessel - when you pump it up you need to ensure the system pressure doesn't does rise ie keep draining down to keep the system pressure at zero. Otherwise you won't get a true vessel pressure.

 

[HarrogateGas]

if by coppice you mean coppice gardens in harrogate then no, i'm from northallerton.

if by coppice your on about some plumbing term then i don't know!

sorry i'm a simpleton i know!LOL

I meant coppice Gardens in Harrogate.there is an estate with about 100 of them...i seem to live there!


I know where in Northallerton you are though......near the railway bridge...nice estate.

 

[ChrisR]

There's a lot of waffle in the FAQ section on boiler pressure Problems covering pressure vessels. I know cos I'm still trying to get it right...

 

[gazthepottertonengineer]

if you are still getting problems after you have checked the expansion vessel i would get your engineer to replace the domestic hot water plate heat exchanger as i have had a few which have pinholed and cause this problem

you could call potteton out for a fixed price of £250 on 08706 096096 which includes all parts VAT etc