Central Heating pump?

[J]

Hi, I was woken up about half an hour ago by a strange noise coming from my airing cupboard.

The hot water is set to come on in the morning,which does normally make a bit of noise, but today I heard what sounded like drilling. When I had a look in the airing cupboard, it sounded more like a washing machine :(

The noise was coming from what I think is a pump, big brown thing with a pipe coming in, and one going out. It has a small black box on the side witha knob you can turn to marks 1, 2 and 3. This was set to 3. I turned it down to 2 and the noise was less, but still that kind of scraping noise. I've now set it to 1 and it sounds perfectly normal.

What is this thing? I assume it's about time it was replaced. Roughly how much would they cost to get replaced? are we talking £50ish, £100 ish, or £200ish, or more :(

Thanks for any advice, and sorry for the poor description, I should still be in bed :(

J

[Grunff]

Badgers?

Yup, that's the pump.

Yes, it's starting to fail, and should be replaced.

A new pump is ~£30-£35.

It should take no more than half an hour to replace, assuming nothing bad happens (like the pump valves refuse to close, or they start leaking).

The description was fine.

[J]

Wow, thanks for the quick reply, very helpful. Time to dig out that plumber's number :)

[john.stumbles]

Probably, but another cause is a blockage between the header tank (the smaller tank in the attic) and the system resulting in the system gradually losing water throiugh evaporation to the point where there's no longer water in the pump which then makes a dreadful racket.

If you open a bleed valve on an upstairs radiator does water come out (possibly preceded by air) or do you get nothing?

Depends on the pipe layout - they can be a pig to get out if their isn't much space around to get spanners or grips in, and as Grunff says the valves may be knackered as well.

[TheScullster]

"Grunff" wrote: >>

If you go down the "call a plumber" route there will be labour as well of course! Guess £100 total depending on location

Phil

[Dave Liquorice]

Bad assumption in my experience. I've done three or four pumps in various properties of mine and none have been "shut the valves, undo the pump nuts, slide out pump, slide in new, do up nuts, open valves, job done". The worst case required the whole pump and valves to be removed as lump, with sections of pipe each side. Not enough free movement in the pipe work to spring the pipes out of the compression joints on the valves.

[Alan]

Or =A3250 if you call BGas!

[Dave Plowman (News)]

That's what I thought. Turned off the valves and set about it. The brass cap nuts on the valves which connected to the cast iron pump were so corroded in the threads I couldn't move them with two 36" Stilsons. So had to cut them off. Then, of course, discovered the valves hadn't actually shut off completely so had to do a panic drain down. Bought some new valves only to discover they and the new pump didn't 'quite' have the same centres relative to the olives on the pipes. By just enough to require extending one pipe, since there was no 'give' in my system.

What should have been a ten minute job took most of the day. The pump replacement was the same make.

[Dave Plowman (News)]

But they're not compression joints but 'butt' joints with washers - or are on my Grunfros pump. So assuming you can undo the cap nuts they should go back enough to give clearance to simply slide the pump out.