glow worm 30ci combi boiler constant repressurising, leaking

Hi folks

At little advice if you please?

Have a glowworm 30ci combi boiler. After foolishly turning the boiler off over Christmas for 3 weeks when we got back middle of Jan, the boiler has been lossing pressure when off overnight, so I've been filling with the bypass loop.

The boiler reports it's got .5 bar every morning.

Two days ago I noticed the pressure display blinking and showing 2.5-3 bar.
This morning before I turned it on, I noticed it was leaking from the overflow... constantly. I could also hear the faintest sound of water [hissing kind of!]

After reading on here drained the boiler and I got a tyre pressure gauge to read the expansion vessel. it reads 1.5 Bar.
I have had, and still do a bit of water leaking from brass fitting [next to the red Pressure Relief Valve.] that is linked to the fill-in loop.

**Just looked in the manual and the 'brass fitting' where water is coming out of is the Reduced Pressure Zone Valve

***HAD the boiler on for 15 mins, and it's just lost pressure, this is the FIRST time this has happened whilst the boiler has been running.

Any thought chaps please?

Cheers

Wilse

Hi, had this problem plenty of times with glowworm boilers. The silver flexible tube inside the boiler (back r.h.s.) connecting black plastic manifold to expansion vessel is blocked - unabling the water to expand into the vessel - thus pressure reaches 3 bar & pressure relief valve comes into action dumping the water outside. My advice buy new pipe. (makers part no 2000801895).You need the r.h.s. panel to be removed for access. If you have no access on the r.h.s. of boiler it's a bloody arkward job. Buy a new pressure relief valve(0020014173) aswell, as they never normally seat properly. If you dont wanna struggle, British Gas send a qualified gas safe registered technical engineer to do a one price fix for £168 .......... or £20 per month and a payment of £99 buys you the repair and full boiler insurance cover for the next 12 month -