Trying to shut off hot water

nordicb

Good day,

Apologies if this has been asked, need some advice. The sink tap in the kitchen needs replacement, however I'm really struggling to understand how to turn the hot water off. In the hot press I can only see 2 valves, one is cold water feed and another tap sits on the top of the tank. I turned both off and while cold water stops immediately, the hot one flows as usual? I traced the pipe, and, looks like, it meets a T connection, one side goes up to the 1st floor bypassing the tank and another one to rads or bathroom sink on the ground floor... Does it mean I need to wait until the whole system (rads, tank, etc) drains?

Thanks in advance.

Wearb

Close the one going into the bottom of the cylinder. If it's closing properly it should stop flow to all your hot taps.

There may also be a valve on your coil in the cylinder, leave that one alone. That is usually not as close to the bottom as the one you need.

nordicb

Thanks for that. There isn't any valve specifically for the cylinder bottom, only one red on top of it.
The cylinder bottom would get closed if I close main cold water supply, but it doesn't stop the hot water as mentioned, so it looks like the water is running backwards from somewhere else, perhaps rads or pipes above the sink... The reason I don't want to drain the 1st floor rads (in case water comes from there), it took me ages to bleed air out of them...

Wearb

The rad circuit has nothing to do with it. The cold water supply to cylinder should stop hot water at taps.
A pic of your cylinder would help. Resize it. My connection spoed is very poor.

PK27

One of the valves in the hot press will turn off the hot water. Is it the kitchen it's still running? This is because the kitchen is downstairs so there's a run of pipe from the hot tank and it takes a while to run off. Open a hot tap in the bathroom first, then go down and open the kitchen hot, it'll drain fast. It's not backing up from anywhere, and it's certainly not mixing with the hearing as you said, they're two separate systems, you wouldnt want to be washing your face with heating water I can assure you!
If the water still won't stop it's possible the valve is bangered, they can snap inside, if this is the case either turn the mains off and drain the tank or tie up the ballcock in the attic tank, average tank will drain in 10 or so minutes through the bath.

nordicb

Thanks everyone, I'll try it again when I get to it withing few days, if no luck, I'll get a picture. The main cold water feed tap seems to work fine as it stops the cold water flow.

Any tips on fitting valve onto a plastic pipe, do I need to use any jointing compound/tape?

Many thanks

PK27

Boss white or uniwhite, take off nuts and rings and rub it into the valve on both ends where the ring seats into it. Won't leak.

Dtp1979

nordicb wrote: »

Thanks everyone, I'll try it again when I get to it withing few days, if no luck, I'll get a picture. The main cold water feed tap seems to work fine as it stops the cold water flow.

Any tips on fitting valve onto a plastic pipe, do I need to use any jointing compound/tape?

Many thanks

If it's pex/acorn the you need to use an insert most importantly. If it's a compression fitting then put some gas(yellow roll) ptfe tape around the compressed olive (not the threads).

nordicb

Ok, thanks everyone for the help. It looks like I had to drain the tank in the attic in the end. That tank has 2 pipes at the bottom of it, one has the valve and another doesn't for some reason. In case of emergency, this is a bit odd, draining the whole tank on the floor is not what I would like be doing!

Those plastic hoses, it's a compression fitting, cut new end, used new inserts and ferrules, made sure mating surfaces are smooth, no leak so far, quite happy about it.

Thanks a lot