Grundfoss UPS2 pump problem

[papa smurf]

Hi All,
My old Grundfoss pump failed some months ago, so I got the direct replacement UPS2 pump and installed it. Everything was fine for a couple of months then the pump went into what I assumed was 'smart' mode,running for 10/15 secs then stopping/starting causing the boiler to go into overheat, as we were going away I didnt have time to investigate so just turned the system off. When we returned the pump had sprung a leak so I got a replacement under warranty, Fitted it,refilled the system (one of my valves had failed) ran up both heating and hot water all was good so turned off the heating leaving the hot water on timed everything fine for a few days then the same problem it has gone into the proportional pressure mode and the boiler goes into overheat.
I checked the output to the pump and when the programmer switches there is constant voltage to the pump, (htg only/HW only/both) and the boiler fires up with no problems. I cant believe I have had two dodgy pumps so............ any suggestions/advice would be well recieved.
Thanks for reading.

 

[tamz]

Fit a different brand pump. Grundfoss pumps are not as smart as they think they are.

 

[SimonG]

Systems full of crap and grundfoss pumps are now pants.

 

[papa smurf]

Thanks, not the answer I was hoping for but somehow the one I expected any suggestions for an alternative?

 

[Ric2013]

Interesting you say that about those pumps. I recently looked at the impeller on a new Grundfos Alpha2L. It had loose bits of plastic hanging off the impeller. Very small, but I wondered what they would do to pump efficiency or whether they would end up running around the system. Wasn't impressed.

Still Grundfos is 'a foundation' not a business as its money goes straight into R and D and there are no shareholders, only the owning family, and, obviously, employees' wages. So it's a fairer business model. I'm a foundation too

 

[SimonG]

Dab.

 

[lucas121]

I need to rethink which pump to buy, We usually only fit grundfos as we were under the impression they are the market leaders.

What's your go to pump then?

 

[Last Plumber]

The pump your talking about can have a "problem/issue", with power surges / spikes. I have come across this twice now. These can be caused by a fluctuation in mains voltage or old equipment in the property.
Is the pump wired from the boiler or independent to it ? Have you had other problems with electricity supply or a power cut recently ? Either way, the answer is a different pump. I personally find they're all much the same now but I do tend to stick to grundfos.

 

[papa smurf]

Think i am just going to replace the pump as suggested, did a bit of digging on the web and it seems this is a problem that has arisen with this model before. my pump is supplied off the boiler but this morning I cabled the pump directly to the mains and ran it up and it did exactly the same so i'm assuming its a pump fault. Bloody annoying but there you go. Thanks for the input.