daining vented central heating with no drain point

14 Sep 2013
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United Kingdom
How can I drain a vented central heating system with no drain point? Is it ok to cut the central heating pipe under the floor downstairs and let it drain in to the ground. After tying up the ball cock.
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Are you sure you don't have a drain point under the floor?
Not advisable to just allow water to drain into the ground.
Do you have any valves in the airing cupboard?
You don't need to drain the system to change a rad like for like.
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il check under the floor to see if theres a valve. I have heard of people taking a radiator of and connecting to the 15mm valve with a nut and oil and polypipe. But the radiators I have are old ones with 3/4 valves.
When you take the old rad off you will need to remove the valve tails from the old rad and fit them to the new one if your leaving the old valves on.
the radiators going in a different position though I need to change the pipe work.
In that case then take off the smallest rad downstairs possible attach an outside tap hosepipe connection to the valve and attach hosepipe.
After you have isolated the feed and expansion tank and put any valves in the airing cupboard in the manual/drain down position.
Make sure you have plenty of old sheets ready next to the rad that you are draining as this method can sometimes be messy ;)
Just be aware though that if the rad that you take off isn't the one you are changing then when you do take the one off you are changing and the pipes drop from above then those pipes will still be full of water.
Get a wet vac from wickes (approx. £40) and suck the water out when you undo the valves. But only undo the valves with a slight turn so that you can nip them up and empty the wet vac.

Cut the radiator off with the radiator valves.
Then loosen a radiator valve at the radiator side.
Allow the radiator to drain into a tray if you don't have something
like a water vac.

Once radiator is empty undo both ends and remove the old radiator.
You can now drain the system with one of the radiator valves.
anyone else here shouting "get a proper plumber in" ?

This sort of work is our 'bread'n'butter', gets a little fractious at times when muppets before us do not seem to think that anyone else will ever have to come back in the future to do anything... even themselves.


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