Draining down the HW Cylinder

[kjhi98]

I need to replace my immersion heater element 2moro,it's a 27inc

fitting to the top of the HW cylinder. Can I get away with just partially draining the HW cylinder to a leve where when I unscrew the old element out water won't flow out?or shoul I drain it down completely? Is the best way to drain it to run a hose from the drain plug to th bath?I don't have a drain tap so will a spanner do?should I WD40 i first? HW cylinder size is 900x450mm & i think it stores 117 litres any idea for the length of time to give it to drain? Any tips much appreciated thanks in advanc

-- kjhi98

[Lurch]

On Thu, 15 Feb 2007 17:39:03 +0000, kjhi98 mused:

Right.

Generally I just drain down until I can remove the element without getting wet, no need to drain it right down.

As long as the edge of the bath is below the level at which you want the tank draining to.

I find the easiest way to drain down is turn off the cold supply to the cylinder, open a downstairs hot tap, open an upstairs hot tap and then just drain off a few litres via the drain off once the hot taps have stopped running.

Yes.

No, although some of the cheaper drain offs have a rubber inside that stays put as you unscrew it. This involves you stripping it down and prodding the washer with a screwdriver, while it is full of water.

Few minutes to drain it to the level you want.

[John Stumbles]

Actually the washer disintegrates and comes of the little tit (technical term) on the bit you're unscrewing and stays in the valve body. If it doesn't want to open don't prod it unless you can cope with it starting and not stopping because the washer's fallen to pieces! Better to loosen the immersion heater and either j-cloth or wet-vac away the dribble as it starts until you've got the level down.

[Lurch]

On Fri, 16 Feb 2007 00:18:02 GMT, John Stumbles mused:

I was struggling with the technical terms there, thanks for filling in the gaps!

Yes, removing the washer with a screwdriver has much the same effect as just jigsawing through the pipe.

The other way to d it is to drill a small hole in the pipe and have at least 2 small bowls, 2 buckets, towels and dustsheets and someone to empty the buckets on hand.

Or, those cheap 'screw on' washing machine valves that pierce the copper pipe, use one of those to drain the system down.

If the drain off is faulty then while the system is empty replace it.

[TheScullster]

"Lurch" wrote

Now that is an idea worth remembering! My drain c*ck is decidedly dodgy.

Phil

[<me9]

I would remove the connection to the top (dome) of the tank, and shove a hose down it and syphonit out , about a bucketfull will be enough. First turn of the cold fill, and drain the hot taps, then when you disconnect the top pipe you'll only get a small quantity to mop up. A towel or two will do to collect the drips.

[John Stumbles]

IME you'll be lucky to get the top connection off the cylinder, but you can probably j-cloth/wet-vac away enough from the immersion boss as you unscrew it to get that off and syphon out from there.

If you have a wet vac and you're in a hard water area you can hoover out some of the half ton of scale you've probably got in the cylinder while you're at it.

And yes do replace the drain-off-c*ck washer while you've got the cylinder empty.