New Grundfos slow to start after 2 weeks, replacement did the same...

[Thandar]

Hi Simon,
The light does come on, and it does try to start, and the impeller moves, about every 3 seconds, but until 2-3 minutes goes by it always fails and then with a whoosh it's off and running.
And Tony, I'm a great fan of Nicolai Tesla, he came up with the old system so I'd be inclined to stick with it!

 

[picasso]

Well it does not see to be electrical so could be the impeller is jammed against the body of the pump, get them to replace the whole pump rather than just the head.

 

[simond]

Seconded

 

[Thandar]

OK I've drained the system and had the pump off for a look, everything looks ok and the water was fairly clear (but wouldn't fancy drinking it!)
The pump moves freely in my hand but does get looser the closer you get to vertically down but I'm presuming this is normal.
Reverse flushed the bearing in case there was dirt in there but nothing nasty came out.
Put back and still the same
I don't think it's fouling the casing as bearing can move a few milimeters if you push on the end under the screw when everything is plumbed back in, if it was hitting the casing I'm thinking it wouldn't budge (it also moved the same amount when it was out)

 

[Thandar]

I did a search on YouTube and found a video from February by Paul Maisons with exactly the same issue, his starts a lot quicker though, so if you want to see what's happening this is it

 

[simond]

Why haven't you put the new body on? Surely you must have at least two lurking around?

 

[Thandar]

I wasn't the installer, they may have one or two but they can't get back for a week or two
Also as they work for 2 weeks and then fail I'm not sure it's a good idea until there is a clear idea of what's happening...but I'm feeling that may not be possible
On my searches I found yet another person with this, they asked Grundfos who said the fix was to get an Alpha, great!
And there was a third but they didn't update to say if it's fixed

 

[Agile]

If Grundfos were to send someone to look they will expect proper access to the pump.

It does not look very adequate to me.

My background is one of where everything was correctly installed for maintenance.

Tony

 

[Dan Robinson]

The answer is clear.

Take it out, get the installer to swap it for a Wilo.

 

[Thandar]

Dan, I like your thinking, I'm fairly sure it's blown the run capacator and probably caused by the changes they made to stop the start torque fusing the boiler relays on the early version of this pump, they did a quick fix and caused another issue...
Tony, I agree the access is horrible to every aspect of this install, unfortunately I'm stuck with what the builder did, and he actually built this house for himself, the construction is great but for a small house there is a ton of copper piping going everywhere!

 

[Agile]

Are you sure it actually has any capacitor?

 

[Thandar]

Hi, yes the new electronic starters still have a run capacator, but it's much smaller than the normal Start cap.
Found a few people with them blowing up, a new one with a better voltage rating is 3 quid from Malplins.
If you look at the video above Tony has kindly replied and switched to a DAB Evosta which doesn't have the same problem, so it's 100% a design issue with the pump

 

[Thandar]

So Wilo Yonos or Yonos Pico? The Pico looks like a new energy efficient versios so I'm guessing it's electronic, also no manual I can find online, not sure how the self-bleed would work in a horizontal installation?
Also there seem to be lots of comments that the non-Pico install needed new gate valves but no idea why, and I have a very tight space...

 

[Thandar]

Hurrah, swapped for a Wilo and it's working perfectly (so far), the install was a right pain, the 2" hex nuts for some reason only has 2 working sides, the third would not accept the spanner so had to rotate the housing every time to get past it. Also the hardest to get to one seems to be cross threaded onto the Grundfos, very hard to get off in that limited space!
Once off an inspection of the Grundfos pipework showed it had developed a very sandy coloured skin inside, which I can't imagine is normal, so maybe it was something in the water that broke it...