SOLVED! ( ... or almost ...) How to safely remove the impeller from a Grundfos UPS32-80 180?

[Breixo]

In my heating system, I have a UPS32-80 attached to a very specific TEKMAR cast iron block. The pump makes a deafening noise so I bought a new UPS32-80 to replace it.
Unfortunately, the new UPS32-80 has a plastic impeller whose water inlet has a larger diameter which prevents the new pump from fitting into the cast block.
My idea is to change the impeller from the old (metallic) pump to the new one but I have no idea how to remove both impellers without damaging the pumps.
Does anyone know how it can be done? Does it require a special tool?

Thanks for your time and attention.

 

[ianmcd]

Those two pump heads look a different size

 

[muggles]

I don't think what you're proposing is possible.

 

[BoilerBob]

I think you could try to undo the nut in the middle but you’ll have to use the old impeller as they are different sizes. It is usually the bearing gone which makes the noise. Bob

 

[Breixo]

Those two pump heads look a different size

The two pumps are dimensionally and electrically identical. The only differences are, the old one was manufactured in 1995 and the new one in 2015 and, internally, the water inlet (center of the impeller) is wider in the new one, probably to strengthen the plastic impeller since, in the old one it is made of sheet metal.

Thanks,

 

[Breixo]

I don't think what you're proposing is possible.

Why not? Unless there is an impediment in fixing the impellers to the respective shafts.
I am looking for someone who has had to replace an impeller in these types of pumps. I do not want to risk breaking something, at this time, outside my house we are at 2ºC and for tonight temperatures of up to -4ºC are expected.
Thanks,

 

[Breixo]

I think you could try to undo the nut in the middle but you’ll have to use the old impeller as they are different sizes. It is usually the bearing gone which makes the noise. Bob

Too risky, I would need someone who has had a similar problem with any of the myriad Grundfos pumps that feature the same type of impeller to shaft attachment.

The noise is as if something (invisible) tripped internally (it is not a constant noise as it usually happens with worn bearings about which I do not have much experience), what has me intrigued is that if I loosen the central (bleed) nut the noise it disappears but obviously water starts to come out.
Thanks,

 

[muggles]

The impellers aren't designed to be replaced. I'd certainly want to try removing one on a pump I don't mind breaking, before trying it on one I do. Incidentally your "new" pump was manufactured in September 2007, are you sure it's actually any good?

 

[just pumps]

Can`t be done.

 

[just pumps]

Too risky, I would need someone who has had a similar problem with any of the myriad Grundfos pumps that feature the same type of impeller to shaft attachment.

The noise is as if something (invisible) tripped internally (it is not a constant noise as it usually happens with worn bearings about which I do not have much experience), what has me intrigued is that if I loosen the central (bleed) nut the noise it disappears but obviously water starts to come out.
Thanks,

By bleeding it you take the load of the shaft bearing hence the change in tone.

 

[JimCrow]

 

[Breixo]

View attachment 216206

Hi, JimCrow,
In the figure that you have sent me, which are the bearings?. It occurs to me that if the bearings are in the stator, perhaps by placing the "old" rotor (with its shaft and immovable impeller) in the new stator, the problem may be solved.
Any suggestions?

 

[just pumps]

Hi, JimCrow,
In the figure that you have sent me, which are the bearings?. It occurs to me that if the bearings are in the stator, perhaps by placing the "old" rotor (with its shaft and immovable impeller) in the new stator, the problem may be solved.
Any suggestions?

Really need the next page to put parts to numbers.

 

[Bodgedbuild]

It wouldn't be as simple as this would it?

 

[sxturbo]

Should be a case of removing the nut in the middle, ideally you should have an impeller puller, so you can jack the impeller off the shaft, it is highly possible the old impeller will break as it's likely to be pretty siezed on the shaft.

The "new" pump is 13 years old, I would have reservations as to the condition of the bearings having been sat in the same position for that time.