How to turn off hot water?

[Phaete]

Problem: No hot water in kitchen sink but hot water works in bathroom sink and bathtub. All cold water taps work.

I initially thought the problem was an airlock but after taking off the hot water tap handle, I found a lot of hardened "gunk" around the headgear nut. I cleaned it with some wire wool and loosened it with some WD-40 and I managed to get a full flow of hot water. So I've identified that the problem is somewhere in the headgear/washer rather than the piping and now I need to turn off the hot water supply.

Turning off the cold water supply is easy - there's a stop valve underneath the sink. The hot water however, does not have one.

After reading relevant pages in my 'B&Q: You Can Do It' book and identifying all the pipework in my house, the only way that I can see how to turn off the hot water supply is by stopping the cold water supply to the hot water cylinder and then draining all the hot water taps.

Is this the correct method or is there another method (or hidden stop valve) that I should follow (look for)?

If correct, do I need to turn off the boiler before draining the hot water cylinder?

Do I need to drain the whole cylinder or can I just partially drain the cylinder?

Also on a side note, my mum seems to think that the hot water in the kitchen is on a different supply to the hot water in the bathroom. In which case, I'd need to follow a completely different method. Could there be any truth to this?

 

[Whitespirit66]

The simplest way is to either turn the main stop tap off, or isolate the supply to the cold (larger) tank in loft. Then just run all the hot taps for 5 or 10 mins until the water stops. Then you can do your work. The B&Q method is fine, if you can identify the correct valve to turn off.

No need to turn off boiler, you won't be loosing more than a couple of inches of water from the top of the cylinder.

Are you sure there isn't an isolation/service valve on the pipework under the sink?

 

[Phaete]

Thanks for the quick reply Whitespirit66.

The problem with those two methods is that we live in a flat with three other flats above ours. We have a feed-and-expansion tank in the airing cupboard but I think the cold water storage cistern is in one of the flats above. Basically - I don't want to trouble them! I think (hope) it would be more convenient to shut off the cold water supply at the stop valve to the hot water cylinder?

I'm pretty sure there isn't a stop valve for the hot water underneath the sink - unless you want me to break apart our cupboard and have a look underneath!

 

[Whitespirit66]

No, don't break anything!

Yes, turn off cold supply to the cylinder. Then run the hot taps until they dry up.

 

[Phaete]

I've just tried to turn off the cold water supply to the hot water cylinder but it is stiff! After a bit of research I can attempt to loosen the packing nut after applying some grease to it. This should hopefully dislodge some of the minerals that have built up around the base. However it's been reccommended that grease suitable for potable water be used. This is very hard to track down in shops. I have (possibly ignorantly) sprayed a bit of WD-40 onto the spindle to no avail. I would try it on the packing nut but I'm a bit cautious because it may not be suitable for the job and also it is flammable. How should I proceed?

 

[JohnD]

does your hot water cylinder have a cold water tank on top of it? that is quite usual in flats

do you know where the water-main stopcock is?

how old is your flat?

photos of the cylinder and pipes would help. also of your boiler, and the pipes around it.

don't try to loosen the nut on that tap until you have turned off the water and drained your tank. WD40 on the spindle won't help much, taps are waterproof. You can try easing it by turning it a little one way, then the other, then back, then a bit more, and repeat

 

[weemick]

i need to turn off the hot water to change a washer there is one red gate valve at the bottom of the hot water tank do i turn that off if i do wouldn't that drain the tank?

 

[JohnD]

same questions as before.

does your hot water cylinder have a cold water tank on top of it? that is quite usual in flats

do you know where the water-main stopcock is?

how old is your flat?

photos of the cylinder and pipes would help. also of your boiler, and the pipes around it.

don't try to loosen the nut on that tap until you have turned off the water and drained your tank. WD40 on the spindle won't help much, taps are waterproof. You can try easing it by turning it a little one way, then the other, then back, then a bit more, and repeat