Cold water cistern overflows when hot water is on.

Postby Stevie-78 » Sat Sep 12, 2009 6:14 pm

Hi, My cold water cistern in the roof constantly overflows when the hot water is on. When I take the top off I can see hot water entering at the bottom from the pipe which should feed cold water to the bottom of the hot water cylinder. I have an in-direct two circuit system and when the hot water is on all four pipes to the hot water cylinder feel hot to touch. It's like there's too much hot water being produced, which is escaping back through both of the cold water feeds. Any ideas on what the problem is and how I fix it?
Thanks, Stevie-78
Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Sat Sep 12, 2009 5:58 pm


Simply Build It

Postby stoneyboy » Sun Sep 13, 2009 8:02 pm

Chances are that the heating coil in the hot water cylinder is failing. When the heating is on this creates pressure in the coil which then feeds into the cylinder.
You probably need specialist help to identify the problem.
Rank: Project Manager
Posts: 2715
Joined: Wed Dec 10, 2008 6:44 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