Replace Myson CP53 - Circulating Pump

Skyhigh

Our circulating pump is on its way out
I've tried bleeding it, etc but it's still whirring so it looks like the impeller is shot.

Either way, I could replace it for another CP53 at £40 but everyone online seem to go for Grundfoss.

The Grundfoss 15/150 is recommended as a CP53 replacement:
https://www.centralheat.co.uk/grundfos-15-50-super-selectric-circulating-pump-5m-head.html
(same delivery head, also meant to be very quiet).

So...

1. Does anyone have any other recommendations for a replacement pump?

2. Are all pumps the same 'size' between in the inlet and outlet?

Our current setup has a shutoff valve above/below the pump, so it looks like a simple jobs to change them over.....only if both the CP53 and the new pump are the same 'size' between the pipes.

I'd assume all circulating pumps would be the same 'size', surely?


Any help is greatly appreciated!


Cheers,

keystone

Skyhigh wrote: »

Our circulating pump is on its way out
I've tried bleeding it, etc but it's still whirring so it looks like the impeller is shot.

Are you sure theres water getting to it?

Are all pumps the same 'size' between in the inlet and outlet?

Not always.

Our current setup has a shutoff valve above/below the pump, so it looks like a simple jobs to change them over.....

assuming they are not seized which 9/10 they will be if they haven't been operated for a while and you'll probably end up replacing them.

I'd assume all circulating pumps would be the same 'size', surely?

Optimist.

I think you should be ensuring that it is definitely the pump first.

Cheers

ormus

are you sure the pump is shot?
if so, then get the grundfoss, the brand leaders, for the sake of the 8 quid extra.

no, pumps do not all have the same spec/dims. however, just a few different pumps will fit the vast majority of domestic CH systems.

gas4you

The CP53 should be the standard dimensions between the valves.

Depending on what valve you have, you may need to replace these, as the 'scew slot' type tend to leak as soon as you touch them and the better gate valve type are longer.

Skyhigh

Hi guys,

Thank you for all the help!

They're gate valves above and below the pump, in fact I found the 'kit' installed for our heating/water - its a Santon Premier Plus Indirect Unvented Cylinder PP150B kit:
http://www.santon.co.uk/docs/PremierPlus_-_Issue_2.pdf
(referred to as 'quality valves' there, but I've double checked them myself).

There's definitely water getting to it, bled the pump a couple of times, bled all the rads, left it 48 hours to settle, also tried increasing the system pressure (as Myson recommends) to try and push out any air - still sounds rough.

It's more of a grinding/whirring noise - which is getting progressively worse and louder - it also gets really loud when the pump is stopping.
(which suggest mechanical grinding/grating to me, since if it was air surely it would get quieter as the impeller slowed down..)


I'm going to order the Grundfoss 15-15 with some spare valves (if they're locked).

I'll try bleeding, etc again. If it works, I'll either end up sending the pump back or replacing it anyhow - it seems like CP53s are the 'worst' of the bunch and don't tend to last long anyhow!

Cheers,