Reducing pipe sizes on the HLP8070 pump

Answer:

Hi William

Reducing the pipe sizes will indeed reduce the flow through the pump, this
may also cause the pump to run hot and reduce its efficiency. This will
result in higher than expected power uptake, wear/damage and quite possibly
pump head height loss depending on the install.

So to sum up I recommend you use the 40mm inlet and 32mm outlet for best
performance and reliability.

If installing ball valves either side of the pump remember to use oversized
valves so not to restrict the pump. This would involve using a 40mm valve
with 32mm reducers on the 32mm side and 50mm valve with 40mm reducers 40mm
side. Ball valves generally have a smaller inner diameter than standard pipe
work so if using 32mm ball valves on the 32mm side for instance you would
restrict flow though the valve and again cause the pump to run hot.

Hope this helps

Regards Tony