Do I need a pump?

[Lesgrandepotato]

We are just at the point of commissioning the UFH and looking at the pumps on each manifold. They look pretty well, weedy. Do we need a pump to take from the thermal store to the manifolds as well as the pump on the loops? 

[ProDave]

The pump in our old house packed up. It was some while before we actually noticed as the manifold pumps were doing a good job of circulating water from the boiler to the manifolds.  It was mainly the hot water heat up that suffered as gravity flow was limited.

 

So I would say no extra pump needed.

 

What does @Nickfromwales say?

[PeterW]

They just need to circulate - how far are you talking ..?? If it’s less than 5m then I’d expect it’s fine. 

[Nickfromwales]

One I did a good while back was convection circulating over 17m of pipe away from the TS which went through an underground trench between the house and the garage ( new plant room ). 

No additinal pump needed afaic, unless it's the longest, most adverse run in history.

Rememver you do need motorised 2-port zone valves ( ZV ) at the TS for each flow as otherwise you'll get them all draining heat from the TS 24/7 with convection circulation .   

Use the orange and grey wires of the 5-wire ZV to switch the respective manifold pump on, as that way you'll never have the pump pulling on a closed or partially open ZV.