New Wilo pump head for Biasi M90D 24S

[chrishutt]

I need to replace the Wilo pump head on a Biasi M90D 24S. Will a standard Wilo pump head fit, and should it be a 5 or 6 metre head pump (existing head is 0.36 Amp, 83 Watt)?

 

[gas4you]

I don't know if it will fit, but I always thought that all system boilers and combis had 6m head pumps in as standard, I stand to be corrected though as I don't know Biasi's.

 

[mehran]

i think you are out of luck there chirs, i believe they use a different impeller for the m90's. i have the biasi pump in the van but i don't have a standard wilo to compare(i think a m96 is a standard head tho)

but i think tim tried but it did not work, http://homegas.co.uk/pump.htm that is what the pumps look like

 

[chrishutt]

Thanks for that, mehran. The old head is exactly like the one on the left with the white impeller. Looks like I'll have to buy the official spare then - bogger, I resent paying inflated prices for these things.

 

[mehran]

well... there is a way, the impeller can be taken out from the old one and put in a new pump as long they are the same generation of pump. i have never try this method but have heard about it working. it depends on the new pump and what is wrong with the old one.

 

[bobthebender]

I have this one off of a M90 24s which is what you want.
where do you live and how soon do you want it ?
It has had 2 months of use and has been in my shed for 3 years but is as good as new and could be yours for postage + a drink but i am going away on thurs till sunday.

 

[chrishutt]

Thanks for the offer bob, but I've got to fit a new pump tomorrow (angry tenant has no hot water or heating). Unless you happen to be in Bristol there's not much chance of getting it in time.

Mehran, any idea how to remove the impeller? Does it just screw onto the shaft?

 

[bobthebender]

It levers out.
Just in from where the o ring sits you can lever out the metal back plate and impeller.Or push from the internal screw.

 

[mehran]

yeh, just use a flat screw driver and pop that plate up.

 

[chrishutt]

Yeh, I worked that one out. What I meant was how do you detach the impeller from the shaft. The problem with the old pump head is that the bearing between the impeller and rotor has failed. You can't replace the bearing without removing the impeller from the shaft.

Thanks anyway.

 

[mehran]

no you change the whole thing, the impeller, the shaft...the whole middle bit inside. sorry i was not clear at all. i have taking the middle part from two pumps in the pictures and swapped them, they do fit.

 

[chrishutt]

But the problem is the failed bearing on the old shaft assembly (impeller, rotor, etc.). There wouldn't be any point in fitting it to a new pump head unless I could swap the bearings or swap the impellers, either of which would require removal of impeller from shaft.

 

[mehran]

yeh i think you can, i have never done it before tho(so don't shout at me if it does not work ). the impeller does not fit but the head does so swap the middle bit. sorry if you miss understood me

 

[Agile]

The first M90s used the standard Wilo pump impeller.

However later boilers used a special with a smaller inlet hole in the impeller. I dont know the exact date but perhaps sometime in 2004.

The one in the picture is the earlier standard Wilo.

Just to confuse the situation there was also a third type with the larger inlet which would appear to fit but then was likely to stick when the bolts were done up.

If you are really clever and stuck for the correct one it IS possible to use the original type but thats not advised.

Tony

 

[chrishutt]

Thanks Tony. This M90D was manufactured in 2003. The impeller inlet is 30mm. It looks the same as the one in the pictures posted. Does that identify it as the standard Wilo?