Securing water before changing tap

[GeePee]

I'm sure this is a simple common question. I had two taps/Valves in my Airing cupboard which enabled me to turn off either Hot or Cold or both supplies in order to work on simple things like changing a washer. On his last visit my Plumber said you don't need these and removed them. Now I don't know how to turn off either the hot or cold water apart from turning off the Main supply in the pavement outside my home. 1. If I use the main supply valve to turn off the water will it secure all taps in the house or just the supply to the roof water tank? 2. I assume I should turn off gas heating boiler before turning off? Guidance would be appreciated. 3. If I turn off Mains supply how is the water contained in the roof tank? Thanks.

 

[Roy_66]

Just a silly question first before folks give you proper answers. Are you sure no stop tap under the sink or in a cupboard. Perhaps could have been boxed in by a kitchen job.

In general I'd favour not having too many valves that you don't need. My airing cupboard has three that I don't use.

Silly other question, is you hot water a pressurised system? or a traditional vented? I note you mention tank in the loft so I guess the later but I could be wrong. If working on the hot then after isolating the supply then I'd empty the tank via the bath, and leave the bath tap open. Also leave the kitchen sink cold tap open.

Myself I would in general turn off the boiler, and make sure others know it's supposed to be off (stick a note on the switch if any doubt).

Cheers,

Roy (Amateur all trades)
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One other thing that should be said here, for a vented system make sure no valves etc. in the vent pipe up to the tank. Otherwise potentially you have a bomb. No joke.

If unsure get a professional in. Also if it's pressurised then always leave it to the Pro's.

Roy

 

[Aquarius]

Good afternoon GeePee,

As Roy suggested, there could and should be a means of isolation upon entering the property. If your plumber has removed a main stopcock, then that’s against good practice, not to mention regulations. If you do indeed have a tank in the loft, there might be an isolation valve on the supply to that, but usually a gate valve to isolate the hot water cylinder.

1. If using the street one, it will isolate all mains feeds including that to your tank.
2. Turning off heating isn’t necessary, unless you’re changing the cylinder, or an associated part.
3. Water wouldn’t be contained in the tank if you’re draining the hot water side, or any tank fed appliances.