Hot water not turning off completely DUPLICATE THREAD 1.

[Colindr]

Hi All

I have a dripping hot water tap in the kitchen so thought this was as good a time as any to replace both taps. You can get new pair of pillar taps approx £15 at DIY stores. I can stop the cold water from the mains stop cock, but I have a hot water tank upstairs in airing cupboard, and although I turned the red gate valve near the tank to shut off the feed, the kitchen tap still continues the flow a little. I left it an hour or so thinking it needed to drain out of the pipes, but still it continued to flow.

https://vid.me/8MxG

Initially I attempted to uncouple the screw connector below the sink but the water coming through the hot water pipe is flowing out too much to replace the tap in the time needed. I quickly re-tightened the connector. Funnily enough since I did this the drip as slowed to 1 every 40 seconds, instead of 1 in every 5. A little more bearable but ideally I would still like to replace both taps. I've heard you can drain the whole tank system but this can create airlocks? Will this be a problem when turning the mains feed on again?

 

[Phill Peck]

Very common with gate valves.

Don't worry about air locks. Yes it can happen but actually is rare.

Go and buy a lever valve
Open the gate valve
Close the cold main
Run hot tap until water stops.
Replace tap
Replace gate valve with aforementioned lever valve
Open cold main

2 birds an all that

 

[Colindr]

Very common with gate valves.

Don't worry about air locks. Yes it can happen but actually is rare.

Go and buy a lever valve
Open the gate valve
Close the cold main
Run hot tap until water stops.
Replace tap
Replace gate valve with aforementioned lever valve
Open cold main

2 birds an all that

Would replacing the gate valve with a lever valve involve cutting through the pipe? I'm trying to avoid doing that. I might give a go at draining the system though. What happens if you have air locks? Does it cause any damage?

 

[Colindr]

Sorry I didn't mean to post a duplicate thread, I had the spinning icon when submitting the topic and must have thought the original thread had not been created;

Thanks for replies, the other thread has been locked so I'll copy to here;

1. The taps you can get for £15 are unlikely to be high quality.
2. Its likely that the red gate valve which controls the flow of water into the base of your hot water cylinder is not shutting off fully. You might try closing it a little further, but don't use too much force or it may shear internally and have to be replaced. Try opening the hot tap, then opening and closing the gate valve a few times, might dislodge the muck and sludge enough.
3. If you've got the space under the kitchen sink:
a. Plenty of old towels down.
b. Isolation valve (preferably full bore) ready to fit and in the "off" position.
c. Clean all paint, muck, Verdigris etc. of hot water pipe.
d. Cut hot water pipe with a pipe slice (not a hacksaw or similar), get the isolation valve on fast.
e. Dry up the water.

Repeat the performance for the cold feed pipe. The with both isolation valves shut you can remove the taps and replace them at your leisure. Don't forget that:

1. If the new taps are to be fitted using tap connectors, you will need new 1/2" fibre washers.
2. If the new taps are to be fitted using flexible connectors, these shouldn't really be fitted directly to the isolation valves. There should be a short piece of copper pipe from the valve ending in a 15mm / 1/2" male iron (made of brass) between them. Check what size connection the new taps have, some will require a 15mm / 3/8" male iron. Toolstation do a solid brass connection piece.
3. If the new taps come with copper tails these will probably be 15mm, and you'll need some copper pipe (perhaps the bits you've removed) and a couple of straight connectors to connect the tail to the isolation valves.

I turned the red gate valve as far as it will go to shut off hot water so as you hinted I don't want to break it. Isolation valves under the sink sound ideal, but I'm not confident enough to cut through the piping, especially with water still running through. May have to get a plumber for that one. I think the Pillar taps I'm looking at are almost like for like replacement with my current one's. It leaves about 50mm length of pipe under the sink to connect to the hot water pipe.

 

[AGAS]

Snatch the fooker , you could get a lever valve for example with a short piece of pipe in one end tightened up in valve with valve fully open,then a hose on that little bit of pipe which leads to outside, so once you've cut the pipe ( not sawing it ) whack on the valve then your not fighting with the pressure of water and you will be surprised how dry your area is , I'll be surprised you'll have spilt a cup full of water.