Low pressure light and 0.3bar. Unable to re pressurise. System not as hot as normal last night so bled some of the radiators and made sure pressure still ok. Usually can repressurise no problem but nothing happening. Can open filling loop tap but can't hear any water going through and pressure not rising. Any suggestions please.

Paul B, January 2007

Same appened to mine and i just attached another filling loop to my heating system and can pressurise system and still get reading from boiler

David, February 2011

> The way I resolved it was to put a hose on the drain cock and backfill.

Brilliant - that worked for me (glowworm 30ci). Thank you!

Mark, January 2010

Apparently the filling loop gets blocked. Quite common.

The way I resolved it was to put a hose on the drain cock and backfill.

Put the running hose in position on the drain cock and open the drain cock (or you will drain the system even more). The filling point knob under the boiler should be closed when you fill from the drain cock side.

Apparently you can clean and unblock the filling loop or replace I do not know how to do this.

BB Essex, August 2009

I had same problem with my Glow Worm 30cxi boilor and could not repressure it and found faulty pressure valve. You have to replace this valve.

Imran, October 2008

Just to let you know the same problem has occurred with my son's boiler and I have discovered that the filler valve needle is plastic and prone to breaking. This therefore stops the filler valve operating when you open it, you have to replace it or manufacture a new needle.

Harry, August 2007

I'm having the same problem. I moved a radiator and tried to repressurise the system by turning the plastic valve. Nothing happened, no flush of water.

The boiler was installed nearly 3 years ago now so I'm out of warranty. Why should this cost so much to get fixed

Mr F, August 2007

Paul..I have the same problem too,partially drained system to move rad.turned plastic valve to re-pressurise,nothing...are we the only ones..Ive been quoted £215 for a Glow worm plumber to fix the problem,could be a design fault!

chris, March 2007

Hi Gas Aid

don't know if you read this but just to let you know filling loop was broken. luckily still under warranty and new one being fitted this week but thanks for your help.

Paul B, January 2007

The water pressure is fine. As far as I can tell there is only one
filling loop valve as I have done this a couple of times before without any problem. thanks for your help. looks like i will need to get someone out to it.

Paul B, January 2007

Are both the filling loop valves open (If fitted with two)?

Is the mains pressure coming into the house suitable or has it dropped real low? The mains pressure needs to be higher than that in the system.


If all is well, possibly the non-return valve as jammed up - Rare on such a new appliance though.

GasAid.co.uk, January 2007