DIY Doctor

Main navigation

Boiler pressure high - Glow Worm 30ci

Postby favemuppet » Tue Mar 04, 2008 10:37 pm

Complete novice so forgive me.

Boiler pressure recently dropped and boiler shut down

Increased pressure as indicated to 1.0 bar (with heating off). When heating come on, pressure goes right up to 2.6 bar, then drops to 2.0 when goes off. Is this normal? Why does instructions say increase to 1.0 for it only to double when in use?

BTW - max pressure I believe is 2.7bar before boiler shuts down.
Rank: Apprentice
Progress to next rank:
Posts: 9
Joined: Tue Dec 04, 2007 1:18 pm


Simply Build It

Postby htg engineer » Wed Mar 05, 2008 8:29 am

Pressurising to 1.0 to 1.5 bar is what is recommended, the pressure will increase slightly when the heating is being used, keep an eye on the pressure gauge over the next few days.

Why did the pressure drop to zero ?

Is there a leak, or did the pressure rise 4.0 bar and then open the pressure relief valve ?

if this happened then there couod be a fault with the boiler, either cold/hot water is mixing with the heating water causing the pressure to rise then discharge outside or the expansion vessel needs re-pressurising or replacing.

Most boilers have a pressure relief valve, which will allow the pressure to rise to about 3.0 - 4.0bar before shutting down the boiler.
htg engineer
Rank: Project Manager
Posts: 3256
Joined: Tue May 22, 2007 5:22 pm

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics