Drain water tank to replace tap?

The message from " snipped-for-privacy@supplied.com" contains these words:

Dunno, but while the tank's drained why not take advantage of of the situation to install a service valve in the outflow? And one under the tap you're replacing.

I've seen them on sale in the sheds. Two wedge shaped rubber plugs with an eyelet you can attach string to.

Yes. You have to plug both the outflow from the tank *and* the expansion pipe (usually curved over the tank). And turn the boiler off before you start.

Traditionally a carrot and a potato were used.

Do not forget to remove the plugs (especially from the expansion pipe) before turning the boiler back on.

Owain

Yes, Drayton branded, very handy but note that you get two. It's no use just blocking up the feed (in the bottom of the tank) you need to plug the vent as well. Only then will no air or water be able to get in thus letting water out when you remove the tap.

With the plugs securely in place there will still be a bit of seepage and if there are other taps and people in the house beware that if any one of them is opened air will rush in. If the point you are working on is lower than the opened tap then water will rush out, only the contents of the pipework but that'll be more than enough and fast enough to spoil your day...

" snipped-for-privacy@supplied.com" wrote in news: snipped-for-privacy@p79g2000cwp.googlegroups.com:

Isn't there a valve, usually a wheel/gate valve, between the Cold water tank and the HW cylinder - there usually is?

Turn it off, open the tap and it will soon run dry ( -ish if it's a gate valve, but we don't mind a drip or two.

If not, plug the outlet - there's almost no pressure, so anything that will block it fairly well and won't let bits disappear into the pipe will do.

And while you're at it install a valve, only make it a full bore lever ball valve

mike

I've never bothered with the vent, the flow stops when the vent pipe empties & no worries about opening taps. As it was DIY I used a plastic cork from a wine bottle with a few turns of pvc tape to fatten it up a bit, starting oversize then removing a turn until it fit, easier than applying tape to a wet cork if too skinny. Finally a nail across the cork near the end stopped it getting lost if I pushed to much.

The drayton plugs are excellent to have in your tool box. However some posters seem to have differing views on use. A single plug in the outlet of the cold water tank will stop the flow to your hot taps so that you can change it. Two plugs are used on the CH expansion tank, one in the outlet, the other in the (22mm) expansion pipe - this will allow a single break to be made in the system, i.e. when changing a radiator valve, and normally limits water loss to less than a pint. Whatever you do don't open two joints. Altogether a great aid for less than £10.

Peter

If you are working on the hot water then this is true. If you are working on the radiator circuit however it is wise to block both!

As a quick stopgap you cna use a carrot.

Good point, I went straight from ice on the inside of the windows to pressurised systems so these niceties are lost on me.

I rarely run out of wine ;-)