Tinkerin' wiv me central heating ...

[Arfa Daily]

Hi all

I need to slightly re-route the pipework to an upstairs radiator. I'm actually doing away with the supply and return pipes that come up through the floor, and moving them into the wall to feed a new ladder-style towel radiator. What's the recommended way of doing this with the least hassle ? It's a bog-standard system from 20 odd years ago. Floor standing boiler downstairs. Header tank in the loft. There is a drain point on the radiator in the utility room where the boiler is. Is it best to partially drain down, until the upstairs part of the system is empty ? If so, best to shut off the upstairs rads and leave them full of water, or drain them as well ?

I seem to remember that when I had a couple of additional rads put onto the downstairs circuit in the conservatory, the plumber that did the job used a trick of tying up the ball valve in the header tank, and sticking a cork in the tank's outlet. He reckoned that all the water would 'hang' in the system, and indeed, he lost almost no water at all as I recall. Of course, as this was downstairs, and the pipes he was breaking into were under a traditional suspended floor, I don't suppose it would have mattered a lot if he had, but obviously, I don't want to risk losing any significant amount of water upstairs, over the top of a plasterboard ceiling ...

Is this a known 'technique' he was using, and something I could do myself, or am I really better to drain down some ? If I do, any issues regarding refilling properly and avoiding air locks ? OK to tie up the ball valve during the job to stop the tank refilling ?

TIA

Arfa

[Heliotrope Smith]

I would really recommend that you partly drain down to 1st floor level. Stop the supply to the F&E tank-tie up the ball valve or turn off the water- , if you have 2 or 3 port valves then latch it back to the manual position and drain down to the required level. You can turn off the upstairs rads but would likely need to open the vent on one of them (probably the one you are working on).

When refilling make sure the motorised valve is still latched back.

[Peter Andrews]

What every DIY plumber needs:

they work!

Peter

[Arfa Daily]

OK Peter. That looks like what the plumber was using. Seems like there are a couple of suppliers within 4 miles of me. What sort of price are we looking at ? I assume that the instructions that come with them are a bit more comprehensive than the pdf on the website ? Or maybe not ? If I wanted to work on a bit of horizontal pipe upstairs, where am I carrying out the mentioned 1 minute drain via the bleed key ? On a downstairs rad ?

Arfa

[Dave Plowman (News)]

If you're not sure about the condition of the system, now would be a good time to drain fully - possibly use a flushing additive (follow instructions), and refill with new inhibitor. If you know the inhibitor is recent then just drain down the minimum needed - close off all gate valves etc on rads to minimise losses.

[Phil Addison]

On Tue, 1 Sep 2009 01:31:02 +0100, "Arfa Daily"

Yes I have a set of these, got them from B&Q years ago for around a fiver.

Never had more than 1/2 pint water drain out before the vacuum stopped it. That's from 15mm pipe, could be a bit worse if you're draining from larger pipe. I routinely head for these if I need to remove a rad or mod the pipework. Bear in mind the 33 feet (1 atmosphere) limit of height of a column of water that can be held by a vacuum. We are in a Victorian house and it works fine between the header tank on the floor of the loft, and below the ground floor joists, which I guess is in the region of a 25 ft column.

The web pdf instructions are all you need, just go to the header tank, stuff one bung in the feed & expansion pipe, and the other in the cold feed outlet at the bottom of the tank. Bleed off a cupful or two of water from e.g. a rad bleed valve (then close it!) and you can open up the system but ONLY at one point of course, though you can saw through a pipe and no water will come out either side (well, a bit might). Actually if you do ned to open it at two points all that happens is that the water between these two poins will drain out from the lower opening. All the rest above the top opening is held by vacuum, and below the lower won't drain anyway.

Don't forget to turn off the c/h first! And do'nt forget to remove them after!!

Definitely a 'must have' for any c/h work.

Phil

[Arfa Daily]

I picked up a pair last Friday, and did the job Saturday. I was (sort of) amazed that not a single drop of water was lost from the cut pipes. I say "sort of" because I remembered my tame plumber using this trick when he added rads to the downstairs circuit for the conservatory, although at the time, I was not sure exactly what he had done, and using what - hence my original question in this thread. Must have been a pair of these. Still, they're in the box of plumbing kit now, and a fine tool addition they are too ! Thanks to Peter Andrews for pointing me at them.

Bit of a story there. I got them from a local Plumb Base. The guy in there looked at me very strangely and said that I was the second person in a day to ask for them, and he hadn't sold any before this, in the last year or more ... Spooky, or someone else who read this thread and thought "Ah - just what *I* need !" ?

Arfa