Powermax 155x, Expansion Vessel and Valve Issues

[Billy Whizz]

Hi All

This is a new post regarding a problem I have asked about before. We have a Powermax 155x Boiler supplying our heating and hot water at home and it has been suffering from pressure loss problems for a week or so now. What happens is that I re-fill the system to 1bar and then when the heating comes on the pressure rises to around 2.5bar. At this point the pressure relief valve vents some of the water to the outside. Consequently the pressure drops until it is at a safe level. This process repeats until the system cuts out due to lack of water... I then have to re-fill.... I think the system also has some trouble maintaining pressure when the heating/hot water is off...

My earlier post, which lead to identification of the expansion vessel as the possible problem, also got the reply:

It may be a duff expansion valve, if it's dripping at less than 3 bar.
The seat can get scored or they can get grit stuck in the valve If the latter, operating the red easing knob will open it and sometimes blow the grit out; usually a new valve is required.

Now I haven't got round to testing and replacing the expansion vessel yet but I don't know where/ can't find the expansion valve. Has anyone got any idea where this is? I also don't have a clue what the red easing knob is... any ideas?

I am also looking for a replacement expansion vessel. The one currently in place is a Zilmet 13B-001836 18 litre variety. Does anyone know where I can get a suitable replacement?

Any help would be gratefully appreciated.

Cheers

 

[Agile]

The symptom is of a faulty expansion vessel.

Have you tried repressurising the existing one? Why do you think its failed?

Tony

 

[Billy Whizz]

The symptom is of a faulty expansion vessel.

Have you tried repressurising the existing one? Why do you think its failed?

Tony

Hi

Thanks for the reply. I am going to try re-pressurising the existing vessel tonight... hopefully, that will fully implicate it.

I have no idea why the vessel should fail in the first place. The entire system is about 6 years old. We had some issues when it was first installed with a leak from a release valve attached to the pipe feeding the vessel. It was removed by a Potterton Engineer who stated we didn't really need it anyway.

I'm quite a novice to this sort of thing but would much rather try and figure things out myself before I call anyone in.... it gives me some good experience in the long run I suppose. Do you have any idea where I can get a replacement vessel if that is truly the problem?

Jamie

 

[Baxi-Remeha]

check out my profile, and send me an email, i may be able to help you out.