Grundfos UPM3 AUTO settings

[OldSpot]

I've got a Grundfos UPM3 AUTO 25 70 130 on an Ivar UFH manifold.

Just trying to work out why you wouldn't just run it in the "Constant Pressure Auto Adapt" mode as opposed to any of the other 3 Constant Pressure settings as this seems to cover all bases?

Or have I completely misunderstood!?

 

 

[John Carroll]

I have never seen any Grundfos Pump working properly in Auto Adapt mode, these had a Auto Adapt mode in PP (proportional pressure) only and generally appeared to run at the lowest PP head which circulated very little through the rads due to the very low head. UFH systems run with a fixed CP head and the loop flowrates are set up manually and are generally fixed, if there are a number of zoned UFH manifolds then the flowrates will probably change slightly depending on the number in service.

 

This is the UPM3 Auto.

 

[OldSpot]

Thanks for your reply John.

As you allude, there is a difference between PP and CP and the UPM3 AUTO has auto adapt for both.

I think in your answer you're talking about the PP not working properly not the CP auto adapt?

 

[John Carroll]

Yes, correct, I don't really see though why it should be required or even work on a UFH manifold,  where, each system will have its own manifold pump so, irrespective of how many zoned systems are on or off, the flowrates shouldn't change?, why don't you switch over to (CP) Auto Adapt and see what effect it has on yout loop flowrates.

[marshian]

5 minutes ago, John Carroll said:

Yes, correct, I don't really see though why it should be required or even work on a UFH manifold,  where, each system will have its own manifold pump so, irrespective of how many zoned systems are on or off, the flowrates shouldn't change?, why don't you switch over to (CP) Auto Adapt and see what effect it has on yout loop flowrates.

 

Having had fun with all the permutations of pump settings on a DAB pump my only advice is to check again after a day and again after a week

 

PP and CP on my pump initially look fine but flow rate drops over a few days - I have no clue why but the only solution for me was to go to a CC setting as there the flow rate stays constant. 

[John Carroll]

@OldSpot will see almost immediately though what effect changing to Auto Adapt does as he can read off the loop flowrates.

 

I have 8 rads on TRVs (old "mechanical" type), I have a 6M Wilo Yonos Pico circ pump where the CP&PP settings can be incrementally changed in 0.1M steps, I have run it for years in PP mode set to 4.6M which gives me the required flowrate of 12.0LPM at a 3.6M head with all TRVs fully calling for heat, the  displayed power will then drop from ~ 22W to ~ 15W when the TRVs are throttling down, works very well, havn't adjusted it for years.