UFH Pump Speed Setting

[Triassic]

I have two under floor heating manifolds, each with a dedicated circulating pump.

On closer inspection, I've found they both pumps have variable speed settings.

Any thoughts as to what speed these pumps should be running at?

 

 

[Adsibob]

24 minutes ago, Triassic said:

I have two under floor heating manifolds, each with a dedicated circulating pump.

On closer inspection, I've found they both pumps have variable speed settings.

Any thoughts as to what speed these pumps should be running at?

 

 

I think standard practice is to put them on the slowest setting, but I’m not sure why.

[ProDave]

Slowest setting that gives the required flow rates on the flow meters.  Both quieter, and uses a little less electricity.

[Nickfromwales]

Yup. Flow can be stupidly low, but still give you the heat you require. 
A lot to do with the type of emitter though, eg thick vs thin ( slab vs screed ) will perform very differently.