Water Pump Chatter

[plenny7]

I've seen a couple of recent threads about water pumps recycling, and pumps coming on intermittently, but this issue is slightly different.

When using the water on our Hunter 33.5, if we try to use a faucet at low flow, the pump will chatter, that is, turn on and off rapidly. If we turn the water on all the way, the pump just runs as long as water flows. When the pump is chattering, the water flow is steady, not pulsating.

I'd prefer to use a low flow when I can to minimize the tank fills required, but I know that chattering on and off like that is bad for the pump motor.

I have no idea how old the pump is. Could it need replacing or a rebuild? Or could what I'm hearing actually be the bypass working? We're new boat owners so all this is new to me. The pump we have is the Flojet 4405-143

 

[kloudie1]

Normal for a low flow at the faucet. There are two ways to fix the annoyance.. the first is by installing an accumulator in the pump discharge pipe. The pump will still run intermittently with the faucet at low flow but the run time and the "off" time will be longer, making it a lot less annoying.
Plan B is to use a variable speed pump so that the pump output matches the demand.. I have one (ShurFlo) and I love it but I understand that there have been a LOT of failures with these things..
I would recommend installing a good sized accumulator to make he pump cycling less annoying.. also check the rubber feet and mounts to make sure that the pump noise is being somewhat isolated.
One in an RV, before/after..

 

[JamesG161]

There are two ways to fix the annoyance..

There is a 3rd way...
Turn off the pump electrical breaker and...
Drink a cold beverage and enjoy the sailing.

pumps coming on intermittently, but this issue is slightly different.

The small diaphragm type pump (like a plumber's friend drain unclogger) and is stopped by a pressure switch (normally ≈30psi).
It doesn't take much of a leak/drip for that system to start, pressurize, and stop.

Mine would do a 2 second start about every hour. I finally found a tiny drop on one fitting.
Jim...

PS: I am not sure how slow flow conserves water? When I brush my teeth or shave, I have a rubber footed cup at the lavatory to fill and use for small water demands.