Turning off hot water

Hi

Recently moved house and I want to change the bathroom taps - sink and bath.

I found the valve for the cold water OK but am having trouble finding anywhere to turn off the hot. I'm not familiar with central heating/water systems but I'll try to describe what we've got.

There's a gas boiler downstairs in the kitchen and a hot water tank in a cupboard upstairs. In the loft are what I think are 2 water tanks - main large one and a smaller one. The pipes around these tanks have 3 red circular on/off valves, one of which I discovered was the cold water for the bathroom, and a couple of lever-type valves.

The only valve-type thing I can see near the hot tank is not what I would say is a "hand" valve - looks more like it needs a wrench or something. I quickly tried to turn it with a spanner but it was VERY tight so I left it alone.

There are no valves in the bathroom apart from the one for the toilet cistern

Any advice welcome.

Thanks

Sounds similar to my setup in an old flat. If so you should have two feeds from the main large cold tank in the loft. One you have correctly identified as the cold feed. The other would be a feed into the base of the hot water tank (the pressure pushes the hot water out the top). There should be a stop tap for this feed somewhere around the tank in the loft where the pipe exits the tank. Otherwise you can use a bung inside the tank as discussed elsewhere on these forums.

The service valve for domestic hot water usually a gate valve may have the red wheel on iut or may just have a square brass end to take a wheel or suitable tool. Buy another gate valve and use the wheel from it.

Be very clear about using the right valve, it is on a 3/4" or 22mm pipe coming down from the space above to the very bottom of the side of the hot water cylinder. There are two other lowish pipes of same size going to cylinder, any valve on these two you must not touch it is to balance the heating system.

Gate valves are notorious for breaking, still turning but no further action where it matters. If there is the slightest hint of trouble I don't use the old gate valve, just bung the tank or do the job live, depending on the job that isn't always realistic.

Bottom line is if you turn off the main stop cock and run the hot taps water will stop eventually.

Then you have to research air locks.

Thanks guys

If I bung the tank (the smaller of the tanks in the loft I presume ??) is there still the risk of airlocks ? Once this is done do I then just run the hot taps until the hot tank is empty ?

Cheers

No still the larger one I would imagine. You would expect to have individual feeds coming from it for cold water and hot water. Look around there should be at least 2 pipes exiting the tank, hopefully each with stopcock (You've identified the cold one already)

Not exactly sure what the smaller one does, think it's an expansion/top up tank for the hot water. Someone competent on this forum can probably let you know

You shouldn't need to run the hot water cylinder empty. Bunging the tank will remove pressure on the entry at the bottom of the cylinder therefore no hot water can be forced out the top. Your hot taps will probably run for a short period then dry up (similar sort of period to the cold ones). Think there's minimal risk of airlock here but again someone more competent may confirm