GRUNDFOS Circulator pump

[Paintbrush]

Hi folks,

I wonder if anyone can help with the removal of the impeller nut.

This is a stock photo but if needed can take a picture of the actual unit.

By removing this nut it allows access to the bearing which needs replacing (on three units).

The pumps in question are these at nearly £200 each, not sure why so expensive but there you go.

Thanks for any help.

 

[Spikey101]

You'll want to check with Grundfos technical but i'm fairly certain they class these types of pumps (Actually most of their water circulators) as unserviceable. I know that the motor repairs/rewinds people we use don't do any work on them, but that might be for any number of reasons. It might very well be a custom bearing knowing Grundfos. If you call them direct they will be able to advise you.

Failing that just go nuts ( ) on it and hope for the best, worst ways you have to fit a new pump and are no worse off.

 

[Dan Robinson]

That is not a nut.

The impellor is forced onto the shaft in the factory.

Don't be a tightwad and buy a new pump.

 

[Paintbrush]

Cheers for the replies.

The nut looks like a cap of some sort hence the slot, not sure but it won't matter if it breaks.

I have Grundfos tech, will give them a bell Monday. Other option is just to buy the cartridge as above complete which is a doddle to fit (four Allen bolts).

In fact, it's probably easier to replace the cartridge in-situ without removing the pump.

 

[Paintbrush]

If I have any success will post back, for anyone that has a noisy pump the 'cartridge' is the bit shown at the end. In essence this has all of the moving parts, bearings ect together with seals.

The rest of the unit has no wearable parts.

https://youtu.be/puRu4xKfGxA

 

[muggles]

Is yours definitely the same as the one in the pic, IE a 25-60 180? What's it come out of?

 

[Paintbrush]

The one fitted is 25 - 50 130 as are the other two. It's a regular 3 bed modern house, quite small.

Bit of a long story really but the two spares were bought to replace the main one this summer. There's a faint whine sometimes but nothing too serious.

Unfortunately both replacements although sold as working had defective bearings.

Ideally I would like to keep one as a spare and the other as a garden pump for mist irrigation (poly tunnel).

That's the plan anyway, best laid plans and all that..

 

[muggles]

In that case, this would do you very nicely http://www.gaspares.co.uk/product/MPCBS23

Alternatively, if you can get the pump body out rather than just changing the head, you could use this http://www.totalboilerspares.com/ourshop/prod_1631625-MPCBS43-GRANT-VORTEX-PRO-6M-WATER-PUMP.html

 

[Paintbrush]

Cheers for that Andrew.

I have one of units in bits which exposes the bearing.

Here's an interesting thing, instead of being a regular ball race it'looks to be metal on metal but immersed in water for lube. I am therefore wondering if old coolant could hinder or wear the bearing over time?

I'll give Grundfos a call Tuesday to see of the cartridges are available, if not will opt for the pump you have recommended above.

 

[D_Hailsham]

The one fitted is 25 - 50 130 as are the other two. It's a regular 3 bed modern house, quite small.

That size house would normally have a 15-50/130. They are much cheaper than the 25-50/130.

 

[Paintbrush]

The one fitted is 25 - 50 130 as are the other two. It's a regular 3 bed modern house, quite small.

That size house would normally have a 15-50/130. They are much cheaper than the 25-50/130.

Thanks, and yes this is what has been said by several with experience. The house next door is slightly bigger but has a higher spec pump than this one.

It is set at the lowest setting which possibly explains over spec.

I spoke with Grundfos tech sales this morning. Bit of a shambles really, they tried to say the parts don't exist until I pointed out Grundfos in the US provide them, ahh.. well we don't, despite the web site offering service kits for all pumps.

Nope, throw it away 200 pounds plus extras.

I guess the UK market just puts up with it and that's that. In terms of repair unless you have a cartridge there's nothing to change, the impeller and shaft appear to be made of some sort of phosphorous metal which helps with friction/running.

Cheers for the replies (tight wad or just someone who hates throwing good stuff away )

 

[Dan Robinson]

If you had the right pump for the job it wouldn't be £200

 

[Paintbrush]

If you had the right pump for the job it wouldn't be £200

Dan, agreed, but this is what has been fitted to these houses or bigger!

Grundfos have a database along their agents, once you give them the serial number it states 'custom OEM pump for system' - they won't deviate off of that.

I could fit the lower spec 15 - 50/130 nad maybe crank it up a tad.

50 is the head but what does the 15 represent?


(That size house would normally have a 15-50/130. They are much cheaper than the 25-50/130.)

 

[D_Hailsham]

Grundfos have a database along their agents, once you give them the serial number it states 'custom OEM pump for system'

What's so special about the system that it needs a non-standard pump?

50 is the head but what does the 15 represent?

It's the diameter of the entry and exit ports - not the same as the connection size.

If you look at the performance curves of the 15-50/130 and the 25-50/130 they are identically the same.

 

[Paintbrush]

Grundfos have a database along their agents, once you give them the serial number it states 'custom OEM pump for system'

What's so special about the system that it needs a non-standard pump?

No idea, but I am sure the same answer came back when I quoted the boiler serial number. OEM pump built for the system manufacture, not available otherwise.

tbh, I have found the replies from Grundfos hopeless if not entirely confusing. You can buy the exact same pump identical but with a different serial number, I have two!

50 is the head but what does the 15 represent?

It's the diameter of the entry and exit ports - not the same as the connection size.

If you look at the performance curves of the 15-50/130 and the 25-50/130 they are identically the same.

Thanks for the helpful info, btw given the main bearing is reliant on water for lubrication would it help adding something to the water?