Is circulating pump big enough?

[BambooCustard]

I have underfloor heating on 3 floors. The boiler is on ground floor. It has an integral circulating pump. The top floor never gets hot. Of course it benefits from hot air rising.

Would a pump a stronger than the grundfoss installed in the ISTOR resolve the problem?

Regards
Paul

 

[Dan Robinson]

An Istor


No, its internal pump won't run 3 floors of ufh, your manifolds should have their own pumps.

 

[BambooCustard]

Yes, an ISTOR. Ho hum.

A pump on the manifold would require switched mains at the manifold. Which would be difficult. Or a pump sited behind the boiler where feed to 2nd/3rd floor starts which would be impossible.

Am curious about this setup - I'm no expert. Presumably the pump shouldn't start till the Uponor UHF valves are open but I have the impression though that the pump starts immediately. For a few minutes it us therefore attempting to circulate watering a closed pipe which I assume is not good for the pump. Is that correct

Presumably swapping in a bigger better pump is not an option?

 

[ALEC1]

up don't always need a pump on each manifold...many UFH installs use one pump for the whole installation...

if the top floor isn't getting hot enough I would start with the obvious things like pressure at the boiler, and as to whether the system is balanced correctly.

 

[Dan Robinson]

An iShite pump will never do 3 floors of ufh. It is lucky to even be working.