New CH Pump

[Mikefearn83]

Currently have a Grundfos UPS 15 50 130 and I think it's on the way out.
I have a large 6 bedroom detached house on a Y Plan system with 19 rads. Is the current pump underpowered and what do you suggest as a replacement. I want to yet something with a bit of power as the system is pretty big.

Thank you.

 

[oilhead]

A UPS 15-60 is a direct replacement, as is any 6 mt head pump that is 130 mm wide. This will give extra flow on a large system.

 

[Mikefearn83]

A UPS 15-60 is a direct replacement, as is any 6 mt head pump that is 130 mm wide. This will give extra flow on a large system.

Thank you very much. Would you go for anything more powerful with the system so big. Flow to the rads is currently not great, or will the one suggested be suitable. The system has been extended twice with a 2 story extention and conservatory also, I think this is half the problem.

Thank you.

 

[Gasguru]

What's the boiler make and model?

Check you're not getting let-by to the cylinder when in heating mode to rule out the mid-position valve.

The UPS 15-50/65 will fit the old back casing (providing it's in good condition).
Any pump with a higher head/flowrate will be commercial class and ££££ eg. UPS2 25-80

 

[Mikefearn83]

3 port value and head has just been charged so that's all good now.
If the 15-50 / 65 is OK then I'll just wack one of those on. Sorry what do you mean about the back casing. Thanks.

 

[Gasguru]

3 port valves are normally restricted to smaller properties...should really be on S plan with perhaps 2 heating zones.
If the pump has restricted access you can leave the back casing of the pump in place...just swap over the motor/impeller head using the 4mm hex head screws...assuming no corrosion in the back casing.
Need to know the boiler...modern condensing models can have significant flow resistance and domestic pumps won't cut it.

 

[Mikefearn83]

Ahh I get you

It's a Worcester bosch gravity open system. I can't remember the model bits it's 24kw I believe.

 

[Gasguru]

Need the model.
By gravity I assume you mean there's a small header cistern feeding the system.

 

[Mikefearn83]

Greenstar Ri 24

Yeah tank in loft

Thanks

 

[oilhead]

Thank you very much. Would you go for anything more powerful with the system so big. Flow to the rads is currently not great, or will the one suggested be suitable. The system has been extended twice with a 2 story extention and conservatory also, I think this is half the problem.

Thank you.

Flow to the rads will be better. Do you know the combined output of your radiators? A high head domestic pump will certainly serve this boiler.A bigger pump will be overkill on a 24kw boiler, and will not help if the boiler struggles.

 

[fixitflav]

Currently have a Grundfos UPS 15 50 130 and I think it's on the way out.
I have a large 6 bedroom detached house on a Y Plan system with 19 rads. Is the current pump under powered and what do you suggest as a replacement. I want to yet something with a bit of power as the system is pretty big.

Thank you.

I replaced my Grundfos UPS 15 50 130 earlier this year with a UPS2. I think the UPS 15 50 130 is unavailable now, superseded by the UPS2. Old one was noisy. I was thinking of just getting the head but complete pump was same price so obv I went for that. Good job as the problem was in the casing, a stainless steel ring had fallen out. I have 10 rads and the UPS2 is fine at minimum speed. The old one was no doubt well down on performance as there was a lot of muck inside and behind the impeller. Cleaned it up and keep it as a spare.

 

[Gasguru]

You could take a punt on a 6 or 6.5 m pump or do the calcs.

The headloss through the RI heat exchanger can be ascertained here...

https://www.worcester-bosch.co.uk/support/literature/download/TB0048

Work out the index circuit etc..