DIY Doctor

Main navigation

Coalfired Back Boiler Hot Water Cylinder Pressurising When Cool

Postby RED1 » Tue Feb 24, 2015 3:00 pm

I have an old cottage with simple coalfired back boiler which heats hot water cylinder, no radiators.
Problem is overflow from hot cylinder into overflow/topup tank, even when fire not on.
Last night fire was out approx 11pm, water was hot but level in overflow tank was ok. This morning approx 7am water from tap was lukewarm. This afternoon, fire still not on, there is a steady dribble pouring from overflow outside onto pavement. Water inlet valve to system shut off all day so excess isn't coming from mains supply.
Any ideas?
Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Tue Feb 24, 2015 2:24 pm


Simply Build It

Postby proptech » Tue Feb 24, 2015 6:34 pm


If your F+E tank has it's water level lower than that in main storage tank, I would think it likely that there is an internal leak in the cylinder primary coil.
Rank: Foreman
Progress to next rank:
Posts: 415
Joined: Wed Dec 05, 2012 11:22 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