Grundfos UPS3 - Central Heating Pump

[Bruce43]

When a pump is switched off does circulating water stop immediately? In other words, is there a bypass within in the pump to allow the water to slow down to a stop?

Thanks for any advice

 

[ShaunCorbs]

It stops pumping but the water doesn’t stop right away but eventually will stop

Hence sometimes you will get the pump pcb lighting up without power

 

[Last Plumber]

No bypass internally.
The pump is not a pump, it is a circulator.

 

[fixitflav]

When a pump is switched off does circulating water stop immediately? In other words, is there a bypass within in the pump to allow the water to slow down to a stop?

Thanks for any advice

Water can flow straight through a centrifugal pump when it's not running, with only a small headloss. So flow will continue for a short while after the pump stops.