Central Heating pump advice required please.......
Central Heating pump advice required please.......
Author
Discussion

Wacky Racer

Original Poster:

40,603 posts

270 months

Wednesday 26th January 2005
quotequote all
To all PH Central Heating guru's...........

Ferg!!!!....

For several weeks now, our central heating pump, which is situated in an airing cupboard, next to our bedroom had started to get very noisy, but only intermittently, usually, just after the heating is switched on, but not always so........

The noise can best be described as a pulsating "droning", keeping the same tempo, but then after about fifteen minutes the noise dies down, and is replaced by a quiet hum, which is normal, I would guess.....

The problem is, this usual happens around 7am, waking everybody up, as the "droning" echoes around the upstairs, but at least it does away with the need of an alarm clock.......

The pump, was probably fitted when the house was new, around thirteen years ago, could the bearings be worn perhaps, and if so can they be replaced, or would we have to buy a new pump???

The pump is pink in colour, and is a GRUNDFOS "Selectric" (max 10 bar), and says model UPS 15-05-130..........................

Also, if a new pump is required, what kind of money are we talking about??



Thanks, as usual, in anticipation....

sparkythecat

8,062 posts

278 months

Wednesday 26th January 2005
quotequote all
Replace the pump. They are dirt cheap, typically £30-£50

<a href="http://www.screwfix.com/app/sfd/cat/cat.jsp?ts=33203&id=102027">www.screwfix.com/app/sfd/cat/cat.jsp?ts=33203&id=102027</a>

A modern pump is bound to be more effficient than one 13 years old and so will save you money as well as being quieter.

If it doesn't already have them, make sure that when you replace your pump, you put isolating valves each side of it. That way you won't have to drain your whole system down to remove the pump should it any time require future attention.



>> Edited by sparkythecat on Wednesday 26th January 10:12

dern

14,055 posts

302 months

Wednesday 26th January 2005
quotequote all
Give your local plumb center (www.plumbcenter.co.uk/) a call. They sell grundfos selectric pumps for about 50 quid. Give them the numbers off yours and they'll sort something suitable out.

Regards,

Mark

Incorrigible

13,668 posts

284 months

Wednesday 26th January 2005
quotequote all
I would guess that in a house of that age it will already have the isolating valves

Dead easy job, might take an hour tops, even if you don't know what you're doing

lazy_b

387 posts

259 months

Wednesday 26th January 2005
quotequote all
It might just be an airlock in the system, especially if the pipes betweeen the boiler and pump have a high point where air can gather.

It happened with our central heating once, shortly after draining and refilling (to install a new radiator). Every time the system switched on in the morning, there was a loud "whoosh" as all the accumulated air went through the pump, followed by the pump humming and gurgling for a short period, until the air had been dispersed around the system. It cured itself in a few weeks (helped by a dose of Fernox), as all the dissolved air boiled out and was vented out of the radiators.

ATG

22,940 posts

295 months

Wednesday 26th January 2005
quotequote all
Only problem you might have is if your installation has been crammed into a small space (Podie??). One benefit of putting isolating valves either side of the pump is that it might allow you to cut out any sections of pipe near the pump that have been inside compression joints rather than trying to recylce half the joint. Good luck. Say goodbye to the skin on your knuckles and put a physiotherapist on standby.

Editted to say lazy_b makes a very good point.

>> Edited by ATG on Wednesday 26th January 11:31

gtr-gaz

5,258 posts

269 months

Wednesday 26th January 2005
quotequote all
All good advice there.

I would just add that the isolating valves will probably be seized. At best they will "let by"

You will more than likely find that you will need to drain part of the system, but it's no big deal.

JonRB

79,299 posts

295 months

Wednesday 26th January 2005
quotequote all
I had the same problem on a Grunfos pump and replacing it cured it. Cost about £45 as I recall.

Being a bit of a numpty, I wrote it all down, took it to my local trade centre and asked the chap on the counter about it and had he come across the make before.
He laughed and told me that about 99% of domestic central heating pumps were Grunfos.

Edit: Yes, you'll probably need new isolating valves too as they usually seize. They're not expensive though.

>> Edited by JonRB on Wednesday 26th January 12:14

cmsapms

708 posts

267 months

Wednesday 26th January 2005
quotequote all

If you get the choice, get a Grundfos Alpha. It should fit, and automatically adjusts the flow depending on the system requirement. This makes it more efficient, and quieter.

Wacky Racer

Original Poster:

40,603 posts

270 months

Wednesday 26th January 2005
quotequote all
Well, the PH massive comes up trumps again..., a very sincere thanks to all the kind Ph'ers who offered advice, just goes to show what a wonderful, helpful forum this is.........

I will try bleeding the pump, but a guess it is more likely that a new one will be required...........

Thanks again......

rev-erend

21,597 posts

307 months

Wednesday 26th January 2005
quotequote all
gtr-gaz said:
All good advice there.

I would just add that the isolating valves will probably be seized. At best they will "let by"

You will more than likely find that you will need to drain part of the system, but it's no big deal.


Following on from this .. you can buy pipe freeze to stop any let by ..

You could also consider autobleed rad valves by Myson
(Aladin Autovent)
http://heatandplumb.com/acatalog/Myson01.html
not cheap at £15 each but do remove rad noise & air.

I've yet to try these - I should add.. but they sound good.

Wacky Racer

Original Poster:

40,603 posts

270 months

Wednesday 26th January 2005
quotequote all
anonymous said:
[redacted]



Thanks Tonker, pass on my thanks to your Dad....

Actually Mrs WR's now retired dad was a time served plumber of 25 years standing, and only lives a mile away, but I did not really want to call him round, as I would be duty bound to buy him an expensive bottle of whisky next Christmas as "payment in kind"....

I will try bleeding tomorrow...

LongQ

13,864 posts

256 months

Wednesday 26th January 2005
quotequote all
FWIW my system has a non-Grundfos pump. The 'other' common pump. Slightly cheaper but you need 2 so you can swap them around when they clog up. Which is about every 2 years.

I had one seize solid - utterly solid - last autumn, after just a few days of humming and 'vibration' noises. It was not very old. I fitted the spare. It made some odd noises just before Xmas, which is when these things always choose to fail.

I now have another one in the airing cupboard - a brand new spare.

Would have brought Grundfos but the purchase was in the middler of may Xmas shopping 2 days before Xmas and the place I was in didn't stock Grundfos and only had one pump left. I bought as a precaution.

Easy swap. Only takes me 10 minutes now - and I am certainly not a plumber.

A long screwdriver works as well as a chisel with less chance of becoming too blunt to use. Chisel has more style though!

norfik dump

2,066 posts

254 months

Thursday 27th January 2005
quotequote all
Had my central heating pump, or as the engineer called it, the impeller, just after Xmas, The new one started making noises very simmilar to the old one, so called them out again to change it again. After reluctantly changing it, he said that the droning noise was a build up of "magnatite", (Black sludge to you & me) in the heating system. He showed me one of the pipes he'd cut to fit the new pump in, I guess the bore of the pipe had been restricted by about half with this black stuff. This, he said was causing the graunching & droning sound from the pump. The only way of clearing this out would be to renew the pipework & possibly the boiler
So far the change on pump & pipework near to the pump has dome the trick, but only time will tell

ferg

15,242 posts

280 months

Thursday 27th January 2005
quotequote all
Sorry Alan...better late than never?

Might be a lack of water causing the 'pulsating', check the header tank has water in it.

If changing it I'd fit a Wilo pump. Grundfos are nice, but their tolerances are such that the smallest bit of crud can stop them firing up on the slower speeds. I buy Grundfos and Wilo for about the same price, £25ish, but in fairly big quantities......

As for changing it...

Make sure the system is cold (i'll explain why in a moment),
Turn off any isolating valves, hopefully gate-type, not screwdriver slot ball-type (which are crap) and loosen the valve-to-pump nut, which is big. If it won't shift buy some pump valves and you may have to cut the nut off and rob one off the new valves. Try to ensure that the water is dripping out at a containable rate, it probably won't stop completely and this is why you should do it cold!!! Dont wind the valves shut mega-tight if they are gate type, they won't open again.

mybrainhurts

90,809 posts

278 months

Friday 28th January 2005
quotequote all
ATG said:
Only problem you might have is if your installation has been crammed into a small space


HA....

I'm still looking for an anorexic pygmy monkey to get at mine......

tallbloke

10,376 posts

306 months

Friday 28th January 2005
quotequote all
LongQ said:
just before Xmas, which is when these things always choose to fail.


How true. I got a call from my tenant who lives in the small back to back I bought years ago on Christmas eve saying the boiler had packed up. Plumbers on the 27th said it'd need a new £150 circuit board and it'd be a week before they'd have it. I tracked the fault to a relay on the circuit board which I got from the local component factors for £2.30 and soldered it in at new year.

Wacky Racer

Original Poster:

40,603 posts

270 months

Friday 28th January 2005
quotequote all
Your not going to believe this...........

The pump has been 100% silent the last two mornings, even though I have not touched it, perhaps it knows it had better behave, or it will end up in the skip.....