I'm changing the taps in my bathroom so I've got to turn the water off under the sink , obviously. Will this stop the central heating from working or does it work off a different supply. We have 2 tanks in the loft one big and one small which I think.is the header tank.
Sorry if this a stupid question only that I need the heating on as the baby isn't well.
Thanks in advance.
Mark
OK - header tank (it will be the small one). So it sounds like a vented system with a HW cylinder too. I'm assuming a standard gas/oil boiler system and nothing funky involving solid fuel? There are possibly some caveats to do with not draining the HW cylinder with the latter.
Yes - in which case, AFAIK the system will run fine for a time with the mains water off - header tank will take care of its needs. That is fed by the mains, but it doesn't need to fill continuously (unless you have a leak). The boiler primary supply *is* the header tank so as long as it contains water the boiler and radiators are happy. I would turn the HW cylinder thermostat as low as it will go if draining the HW cylinder - it will stop the boiler cycling trying to heat nothing in the case the rooms are already hot enough.
More usefully, you *may* have an isolation valve near the HW cylinder which will isolate the supply to the hot taps. Look for a pipe, usually 22mm (3/4 inch in old money) coming off the top of the cylinder and which has a valve (may or may not be adjacent to the tank, may be further along the run), it's probably that one. Although, if it's a gate valve (big brass thing with a wheel) it's quite possibly seized if it's not been exercised regularly.
There should also be an isolation valve on the feed to taps off the CW tank (larger tank). Same caveat if it's a gate valve.
I would have said "should have a valve", but my system in my rented house doesn't because it was installed by a bunch of corner cutting cheapskates, so don't be worried if you can't find one.
Not forgetting, that if this valve doesn't work/exist and you do need to shut off at the main c*ck, you need to drain the HW cylinder[1] and the large CW tank out first otherwise you'll get a most impressive flood when you take the taps off. Just open the bath taps in the same room as you are working until water stops coming out.
Watch the basin - just might have a direct mains feed - so main c*ck for this.
You might consider taking the chance to fit isolator valves to the HW and/or CW tap/shower feeds though if you have to drain the large tank and cylinder
- I'd recommend a "full bore" lever valve, less trouble than gate valves and doesn't restrict the flow much, easy to operate.
If you are unsure, post a photo or three, on the web, of relevant bits of the pipe work - it's much easier to point something out than talk in a lot of "ifs and maybes"
HTH
Tim
[1] If the HW cylinder is on the floor below the bathroom, then it won't actually drain and doesn't need to.
The hot water cylinder won't drain via the taps, as its output is from the top. If the valves work, the cold feed to the hot tank should cut off the hot water, if not run the taps to drain the cold tank, possibly via the hot tank.
If there is no/nonworking valve in the feed to the cylinder, to save draining the cold tank you can stick a rubber bung (or failing that a carrot!) into the cold feed pipe where it exits the cold water tank (i.e. reach into the water in the tank and plug the exit hole)
It *should* run for ages with no feed to the header tank. Some installers didn't even fit one and you had to top up the tank manually - usually only about every other year.
Yep. They did that in about 1952.
The central heating is entirely separate from the mains cold water supply - apart from the feed to the small tank - whose ball valve opens once in a blue moon to replace evaporation or leakage. So turning the water off will
*not* affect the heating.If you're also changing the hot taps, you'll need to interrupt the hot supply. Hopefully there will be a gate valve in the cold feed which comes from the large header tank to the bottom of the hot cylinder. If so, turn it off and run the hot taps until water stops flowing - should be no more than a couple of minutes. If there *isn't* a gate valve, find the outlet at the bottom of the large header tank, reach down inside, and stick a cork in it.
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