Help! - Central Heating Pump Question

[Lord Flathead]

Bloody typical, our central heating pump has just given up the ghost

It is a Grundfoss, but being as we will rip out the whole system in the summer I am planning on replacing it with a cheapo pump to get us running again.

The question I have is: Are all the bodies the same distance between both flanges i.e. will any pump have the same footprint, or will I have to stick to another Grundfoss?

Any help greatly appreciated as I have a dinner party tonight (how bloody typcial is that??), and am trying to get this changed before Buy & Queue closes at 8pm.

[browno]

Should be standard - I replaced both the pumps on the system at my old house, and pumps from the local B&Q slotted straight on... HTH

[Lord Flathead]

Ah great, thankyou for your prompt reply. Off I go to that B/Q.

[SS2.]

Any that you can buy from your local DIY store should be the same size..

But are you sure the current pump has actually given up the ghost ?

[maser_spyder]

Lord Flathead said:

Bloody typical, our central heating pump has just given up the ghost

It is a Grundfoss, but being as we will rip out the whole system in the summer I am planning on replacing it with a cheapo pump to get us running again.

The question I have is: Are all the bodies the same distance between both flanges i.e. will any pump have the same footprint, or will I have to stick to another Grundfoss?

Any help greatly appreciated as I have a dinner party tonight (how bloody typcial is that??), and am trying to get this changed before Buy & Queue closes at 8pm.

You'll find they are all the same size. For peace of mind (given the one you have is buggered) take it out and with you when you pick up the replacement, can't do any harm to double check.

Grundfoss is the de-facto pump, although there are a couple of others on the market, you'll struggle to find one that isn't a Grundfoss!

Might be teaching you to suck eggs here, but for changing it, you should find a gate valve (or other type of valve), both above and below the pump. Turn off both valves, a bit of water in the pump will leak out, but you won't need to drain down the whole system.

Unless it's hard to get to, should be easy to change, 30 minute job once you have the pump.

If you're anywhere near Cheltenham, I actually have a spare CH pump (old and a little noisy, but perfectly functional) that you're welcome to, gratis.

[Ozone]

I had the same problem with a pump of the same name a few years ago. It had seized because the header tank had run dry, the ballcock was jammed, and there was air in the system. I shut the valves off on either side of it, took it out and put WD40 in the impeller bearings and it lasted for years.

[NDA]

SS2. said:

But are you sure the current pump has actually given up the ghost ?

My thoughts too. There's a large chrome screw head at the front, this can normally be removed to see if the pump will rotate.



NDA is not a plumber and, as such, is not regulated to give any such advice. The value of your house may go up or down as a result and these vouchers may not be exchanged for food

[Lord Flathead]

SS2. said:

Any that you can buy from your local DIY store should be the same size..

But are you sure the current pump has actually given up the ghost ?

Yes, it was my fault completely, I decided in my wisdom to add some powerflush to the system.. was supposed to be in there for a couple of hours IRC, but I forgot about it and it was in there a week

When I came to flush the system out, I found species that David Bellamy had not discovered in the waste water, and I think all the debris were clogging the pump. On Christmas Eve, the boiler actually cut out due to overtemp, but I didn't realize at the time that the pump was turning properly. I took the cap off when the system was cold today, and it was hard to turn the impeller with a screwdriver. When swutched on, my voltmeter show 243v at the pump but not spinning.

[sploosh]

Give it a few good whacks with a hammer - often frees things up and costs nowt to try.

[maser_spyder]

sploosh said:

Give it a few good whacks with a hammer - often frees things up and costs nowt to try.

Not going to knacker an already pump, and at the least might get you out of trouble until tomorrow....

I did this on a pump three years ago, and it's still going now!

[SS2.]

Lord Flathead said:

SS2. said:

Any that you can buy from your local DIY store should be the same size..

But are you sure the current pump has actually given up the ghost ?

Yes, it was my fault completely, I decided in my wisdom to add some powerflush to the system.. was supposed to be in there for a couple of hours IRC, but I forgot about it and it was in there a week

When I came to flush the system out, I found species that David Bellamy had not discovered in the waste water, and I think all the debris were clogging the pump. On Christmas Eve, the boiler actually cut out due to overtemp, but I didn't realize at the time that the pump was turning properly. I took the cap off when the system was cold today, and it was hard to turn the impeller with a screwdriver. When swutched on, my voltmeter show 243v at the pump but not spinning.

Long shot, but you before you bin the pump, you could try undoing the Allen bolts which hold the pump together and removing any debris which might be blocking / jamming the impellor.

Edited by SS2. on Saturday 2nd January 18:20

[Festive Ferg]

Whatever else you do, DON'T expect the isolating walves to hold back the water. If they do it's a bonus.

[maser_spyder]

Festive Ferg said:

Whatever else you do, DON'T expect the isolating walves to hold back the water. If they do it's a bonus.

Better trying them than not though!

I was lucky with mine, but good point!

[SS2.]

Festive Ferg said:

..DON'T expect the isolating walves to hold back the water.

[Festive Ferg]

maser_spyder said:

Better trying them than not though!

Oh certainly, i just wouldn't want him to crash into it and leave himself nowhere to go.
Crack the nuts and wait 'till the water stops, but trickling out. Just don't be surprised if (when!) it doesn't stop.

[maser_spyder]

Well, it's all gone quiet....

So either OP is cooking for dinner guests, or mopping up after a failed pump valve....

[Lord Flathead]

Well that wasn't quite the 30 minutes job I had expected

Firstly, the pump came minus the sealing rings so I had to dash back to B&Q and extract two from another box.. as some thieving bastewards had pinched mine

Suitably armed, the Lord of the Rings returned again, to a less progressed dinner which was now candle-lit. It seems that while I was out, there was a power outage. This was a local one, ie just my house as the RCD had tripped out which was a problem because no one had tried to find the distribution board. My guests gave me a cheer when I returned, they were suitably lubricated and I was down about two bottles of wine (thank God for Virgin Wines Crimbo special). Changing hat from plumber to electrician it was noted that the fault was persistant and the breakers would not reset (downstairs lights and upstairs power). As if by magic, Fergs' power of suggestion was correct and the previously dry non-weeping isolator valves had changed their minds in my absense and had been leaking into a computer power supply in the bathroom and also the ceiling rose of the lights below. To make matters worse, water had also dripped into my dated Potterton 2000 controller so I had to remove that and strip it down to dry it off. Guests witnessed me pouring wine with one hand while drying the controller with a hair dryer in the other

By 10pm, everyone was drunk, the joint was as dry as the Gobi Desert. My sauce developed a kevlar skin, the parsnips had been case-hardeneed, and even the petit-poir tasted wrong.

I ran out of wine glasses (broke 3 over the holiday period!) and the drain in the sink blocked for obvious reason (although the kevlar sauce may have had something to do with it).

All in all a fantastic night, great company, and everyone was far too merry to worry about the cooking. The house is nice and warm now for the first time in a long time. Thanks for the pointers - PH come through again

[mybrainhurts]

Well done that man...

Bit late now, but there are two sizes of pump.

you got, errrrr, lucky......

[Ferg]

Sorry.
Wish I'd been wrong, but 30 years of plumbing tell me otherwise.

[SS2.]

Lord Flathead said:

The house is nice and warm now for the first time in a long time.

Glad its all sorted..