how to drain down hot water cylinder to replace immersion

Postby scotto » Wed Jun 18, 2008 6:02 pm

to change immersion heater in top of cylinder i believe i need to drain some water from the cylinder but there does not appear to be a drain cock. is there another way of draining the cylinder?
Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Wed Jun 18, 2008 5:39 pm


Simply Build It

Postby AdamsHeating » Wed Aug 13, 2008 1:42 pm

hi mate,

isolate the cold water supply to the tank that feed the cylinder. Now open all you taps that are fed by the tank/cylinder until they are showing no more water.

Now theoretically your cylinder will still be full but there will be no pressure forcing the water out (cold water storage empty as supple isolated). There will be a little bit of water left just above where the hot water leaves the cylinder, how much depends on how well the system was installed. Slowly undo the immersion heater to test how much water is left in the pipe (at this point there may be a bit of water so I'd advise a bucket or a bin bag, one without holes!) and let it drain down.

Eventually the water should stop coming and you should be able to remove the immersion heater.

don't want to sound like an old man but here goes... please isolate the electrical supply to the immersion heater before you do anything else!

If that doesn't work then I don't know, that's how I changed one before!


Rank: Ganger
Progress to next rank:
Posts: 121
Joined: Fri Aug 08, 2008 10:49 am

Postby TOPSPARK » Wed Aug 13, 2008 3:16 pm

Yes turn off cold water stop tap and then open hot tap on both basin and sink also tie up ball valve on header tank to stop header tank filling main tank back up. then you can take out immersion heater coil. when doing this dont forget to isolate electric supply for immersion heater
Rank: Ganger
Progress to next rank:
Posts: 97
Joined: Fri Jul 25, 2008 9:44 pm

Postby Steve the gas » Fri Aug 15, 2008 6:52 pm

I'm thinkng he would have fixed it by now, it was a post from JUNE
Steve the gas
Rank: Site Agent
Progress to next rank:
Posts: 780
Joined: Sun May 04, 2008 7:07 am

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