Isolate Shower Mixer Tap

[BigRooster]

I needed to isolate my thermostatic mixer shower taps which comes directly from my Bosch worchester green star si . There's no isolater between the shower and boiler so is there any way of doing it . I was thinking that maybe turning off water from the stop tap and switching off boiler any advice would be great .

[Dodger666]

If your boiler is a combination boiler you can turn the water off at the main stop tap. You can switch the boiler off but it won't come on if there's no water supply.

[The Builder]

Yes, just turn off the cold supply to the combi, or at the rising main if it's easier.

Simply fit isolator valves in the hot and the cold. You can get them with a screwdriver slot or a handle.

[BigRooster]

The plumbing manifold the valves seem to have a flat head screw slot I take it I could turn these which should stop hot water flowing to the shower

[Dodger666]

If you can do that you will have to shut off the cold water supply too. I assume your shower mixer will have a hot & cold water supply.

[BigRooster]

Yes it has both but wasn't sure how easy it was to shut off the hot water valve on the manifold to the shower

[Dodger666]

Why do you have to isolate the mixer valve?

[BigRooster]

To remove it and change the cartridge inside

[Dodger666]

If you already have the replacement cartridge I'd be inclined just to turn the cold water supply off.

[BigRooster]

If I turn the cold water supply off at stop valve under the sink after running the water out of the system would I need repressure the boiler or would it stay the same

[Dodger666]

You must shut off your main water stopcock. You may not have to empty the hot & cold pipes. If the mixer valve is fed from the bottom there shouldn't be much leakage, any leakage would go into your bath/shower anyway. I'm assuming it's a shower mixer valve. This procedure will not affect the boiler pressure so you don't have to worry about that.

Just shut off the water, empty pipes if necessary, change cartridge, turn water back on. Then have a shower and a cup of coffee.

If it all sounds too much get someone else to do it for you.

[BigRooster]

No should be fine do at the weekend cheers for all the help guys