Glow Worm Flexicom 18 - Pressure Vessel

SaabmanBOF · 15 Feb 2019 at 10:34

There's always bloody SOMETHING...

Draining my boiler yesterday, I opened the Schrader valve on the expansion vessel, and water came out! I thought/think it has a rubber bladder inside it, and if so, that has sprung a leak.

What function does the expansion vessel perform, and more to the point, does it matter if the rubber bladder inside it is leaking? If the inlet/outlet is at the bottom, there will still be pressurised air inside it, so can I just leave it as it is, or do I need to get it fixed? I run my system at a cold pressure of about 1.1 bar.

Fireskull · 15 Feb 2019 at 11:03

Sounds like the diaphragm inside has failed, whole vessel will need to be replaced, they're pretty cheap.

SaabmanBOF · 15 Feb 2019 at 11:37

Thank you. They certainly don't cost a lot, but I wonder if I just leave it, will it make much difference?

With the inlet/outlet at the bottom, if it's partially full of air (which it is - there's no water coming out of the Schrader valve with the system at 1.1 bar), it should fulfil the expansion pressure damping function well enough. I know the air inside will eventually be absorbed by water, but very slowly, and I can check the water level inside easily enough by cracking the Schrader valve with the system up to temperature.

NoobCannon · 15 Feb 2019 at 13:49

SaabmanBOF said:
Thank you. They certainly don't cost a lot, but I wonder if I just leave it, will it make much difference?

With the inlet/outlet at the bottom, if it's partially full of air (which it is - there's no water coming out of the Schrader valve with the system at 1.1 bar), it should fulfil the expansion pressure damping function well enough. I know the air inside will eventually be absorbed by water, but very slowly, and I can check the water level inside easily enough by cracking the Schrader valve with the system up to temperature.

Why not just fix it now You Know its broken. Dont do things half assed as they cause
More problrms in the long run

Fireskull · 15 Feb 2019 at 13:58

^ This basically, its a pretty important part of the system, and will cause problems with it not working properly, surprised you don't already have pressure problems because of it or it's releasing water through the prv.

SaabmanBOF · 19 Feb 2019 at 20:29

Well, no problems so far, and it's holding steady pressure, but I take your point, gentlemen; they wouldn't fit an internal diaphragm just to use up some spare left-over rubber sheeting...

I'll fit a new one.