Glowworm 30ci loss of pressure

[radio_engineer]

Gloworm 30ci suffers loss of pressure. Works fine but when cold pressure drops under 0.5 bar. No leaks noticable except when filling up. Some scale on metal under PZV brass drain off. I suspect leak on Reduced Pressure Zone Valve. As I try to fill boiler there is leak on brass part of this valve. This apparently is common but this valve leaks when pressure reaches .6 or 0.7 bar so much it is not possible to fill boiler to 1.5 bar. I had to use screwdriver with cloth over the tip to close RPZdrain off hole to fill boiler.

Where can I get replacement part in NW London. I have searched net but could not fing part no.

Any advice on part no, for RPZ or web site. Can this be cleaned up or repaired?

PRV was changed did not fix problem. Boiler engineer has given up after 3 visits. No leaks on pipes or radiators.

 

[radio_engineer]

Hi,

Still same problem with loss of pressure does anyone agree/disagree that RPZ valve ( Reduced Pressure Zone) could be problem?

 

[Alfredo]

1) What pressure are you trying to fill it to..should be 1 bar when cold
2)When central heating is hot what is the pressure reading? does it rise quicky to in excess of 2.5bar
3) If you switch off CH and just use Hot Water..does it still lose pressure.
4) have you checked the pressure relief valve pipe outside to see if it is leaking when boiler is operating.

Reduced Pressure Zone valve is supposed to drip when you fill it..don;t know why, but they all do, so that is probably a red herring unless it is dripping ALL the time..in which case..yes its probably faulty.

Most likely causes are:

1) Blocked flexi pipe between pump and expansion vessel
2) leak on the system
3) leaking pressure relief valve

Alfredo

 

[ChrisR]

Careful, they changed it, easy to get wrong one.

 

[radio_engineer]

Just to update forum on outcome.

I have apparently fixed the problem, it was blocked pipe hose (flexi). Only problem it may be now that whatever particle was blocking the pipe may block it again as the particle was flushed in the pressure expansion reservoir.

The other problem I have noticed is that filter on CH flow can't be taken out for cleaning. It must be seized due to scale etc. I have attempted to force the filter out but it is made of plastic and in plastic housing so I am concerned I may damage the body of the filter housing.

Thanks for help.