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Start Stop for booster Pumps

Start Stop for booster Pumps

Start Stop for booster Pumps

(OP)
Hello everbody

can anyone please help me in answering the below questions

1. what is the logic behind number of start/stops for domestic water pumps, is there any formula or calculations for the same ?

2. How to calculate the expansion tank size for the booster pumps, is the tanks size also related to the number of starts and stops of the pump??

thanks

RE: Start Stop for booster Pumps

Booster pumps can either be constant speed (older design type) or variable speed.

With a constant speed, the expansion tank is a must. With variable speed, it is a good idea to buffer the start up and shut down of the pumps.

With a variable speed pump, the on/off cycle is not as critical since it is not a full start, but I would assume 5-10 minutes between starts.

For sizing the tank, the manufacturers typically have a sizing page on their website. I use amtrol and look at the well pump expansion tank section.

RE: Start Stop for booster Pumps

To expand a little bit, electric motors don't like stop/start cycles, which reduce their life because of the extra heat resulting from the starting current. Somewhere deep in the fine print, motor manufacturers publish a limit in starts per hour above which they would prefer to not honor a warranty. Motors that are sold into price sensitive markets (like hydronics) are built with relatively little safety factor for anything, including stop/start cycles.

Mike Halloran
Pembroke Pines, FL, USA

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