On 10/04/2021 19:21, Tim Lamb wrote:


Not really been reading this but the *builders* fitted a double monsoon
shower pump to the farmhouse. Gravity system with about 2.0m head from
loft tank. Tanks to pump distance within 3-4m.

Initial experience was that the pump exceeded the top up feed to the hot
tank. An Essex flange was fitted but there were still occasions when an
air lock stopped hot water flow to the main bathroom.

I believe there is a reed switch energising the pump which must rely on
gravity flow. Is this linked to their pipe run limit?


I don't see why. If there is sufficient gravity flow between tank and
shower to trigger the flow switch, why should it matter where in the run
that switch is placed?

There are actually two types of Monsoon pump - standard and universal.
The standard ones need a positive head - and enough gravity flow to
trigger the flow switch. The universal ones can work with a negative
head. They also have a pressure vessel and a pressure switch. Presumably
the pressure drops when a tap is opened, and triggers the pressure switch.
--
Cheers,
Roger