Drain kitchen taps but save hot water in cylinder?

22 Oct 2007
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United Kingdom
Replacing my kitchen at the moment, just removing old sink.

Have turned off main stopcock and drained mains fed cold tap, but the stopcocks by my hot water cylinder are seized and I don't want to drain a whole cylinder of hot water.

I have a solution in my head that should work, can someone verify it please!?

If I drain the cold water tank in the loft via the bathroom cold taps, then there will be no head of water to push my hot water out of the cylinder to the kitchen?

Or (lightbulb moment) will opening the kitchen tap basically syphon out the hot water in the cylinder leaving me in the same position as if I had just drained the whole lot via the cylinder anyway? When I turn on the hot tap, I'll drain off the water left in the pipes between empty cold tank and cylinder, then as soon as air enters the cylinder from the feed pipe, it will bubble to the top of the tank and stop the syphoning effect?

Any help appreciated...thanks :)
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leaving the hot tap open won't drain the cylinder just the tank in loft if you have isolated the ball valve and when thats empty the hot will stop running.
why don't you just bung the oulet in the cws tank and no need to drain any tanks and then you can replace the faulty gate valve as well.
Will see if I can use the bungs...they didn't work in central heating tank as it has slots which prevent a seal.

I don't want to drain the system via the hot tap as I have a whole cylinder of hot water sitting there, obviously it will drain all the hot and it will be replaced by the cold from the tank.
yes will loose your hot water try bunging.
DON'T bung the vent just the feed in the tank
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Thanks for the help, couldn't bung as again the outlets have grooves in them which prevents a seal :(

Drained the cold water tank via the bathroom taps and managed to save my hot water, worked a treat :)

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