Help with grundfos re-circulating pump.

[oldbutnotdead]

Fair dos. If you can get at the dhw pipework (including the return,) and insulate it that'll help a lot.
Then put a timeswitch on the thing so you get quick hot water during the times you usually need it (this is where the posh pumps pay for themselves).
Then have a think about other override triggers (PIR sensor was suggested by someone), you can link (via relay) any electrical circuit to that pump so one to ponder would be using the lighting circuit in that far bathroom to trigger the pump.

 

[Gasguru]

The UPM3 technical manual from Grundfos shows the multitude of versions available...and the stainless steel or plastic back casing versions should have DHW printed on the front.
Try a magnet on the back casing..that pump looks to be a standard pump ie. unsuitable.

 

[picasso]

According to Grundfos the upm3 auto L is a direct replacement for the alpha2 L which is suitable for domestic hot water.

 

[Gasguru]

The Grundfos website is a shambles, that's a misleading title...I think they've cut and pasted from the commercial pump range where indeed they often use a stainless back casing.

The Alpha2 LN version is suitable for secondary circulation... https://product-selection.grundfos.com/al/products/alpha/alpha2-l-n?tab=models

or the Alpha2 N... https://product-selection.grundfos.com/al/products/alpha/alpha2-n?tab=models

or the dedicated DHW brass back cased pumps

or the UPM3 DHW version but this version only appears to be avialable as an OEM part... https://www.google.co.uk/url?sa=t&r...T04_Free.pdf&usg=AOvVaw0fsV9q-1omrhHF0hFMc-9e

 

[picasso]

You would think a company the size of Grundfos would get it right if they say a pump is a direct replacement for another pump, my apologies if it does turn out the pump is the wrong type.

 

[Gasguru]

The larger the company the worse the documentation....take a look at Honeywell.

 

[polesapart]

Then maybe I was misled, too.

Next question; is the plastic pipework visible in the the third picture suitable for a secondary loop?

AFAIK some manufacturers don't warrant this, certainly not for 24/7 operation.

 

[Gasguru]

The OP needs to check with the pipe manufacturer...the specs aren't very clear whether they deem say an hours use in the peak demand times as continuous use.
Needs a proper DHW secondary pump though.