Plumbing maintainance question...

[tropicalescape]

Why does water pump cycle in the gally sink when not being used? in Oday 39. It sporadically makes a humming noises throughtout the day even without use...

[tropicalescape]

Any replys would be greatly appericated, thank you for any help in advance!!!

[shorebird]

If its on a pressure switch, you may have a slow leak somewhere, usually, but not always, a leaky faucet. Make sure you turn all faucets off tightly, and check for a periodic drip. If ok, check for a leak somewhere else in the system.

[sailvayu]

THere are several reasons other than a water leak that could cause cycling but that is a good place to start. If your bilge pump cycles as well that is a good clue there could be a leak in the system. Low pressure or a water logged expansion tank will cause pump cycling. Also a leaking check valve in the pump or system can be at fault. These problems can be annoying but often not hard to fix.

[peghall]

If it's a diaphragm pump, diaphragms are rubber and have a finite lifespan (typically anywhere from 10 years live-aboard to 20 years for they typical weekend warrior). The first little bitty pinhole leak causes the pressure to drop just enough to make the pump cycle VERY briefly ("brrrp") every few hours...then gradually more frequently and a little longer each time...till finally the pump will run continually without moving any water.

You CAN buy a rebuild kit or just a diaphragm kit, but rebuild kits cost almost as much as a new pump--IF you can still get the one you need for your pump--and if you only replace the diaphragm, the pressure switch will be next thing to go. Water pumps have really improved over the years so, adding all that up, it makes more sense to replace the pump (2.8 gpm is the right size for 99% of boats) and rebuild the old one to keep as spare that you'll prob'ly never need.

[skipmac]

Like Peg and sailvayu said.

Your water pump has a built in pressure switch that causes it to come on when you turn on the water OR if the water pressure drops for any other reason, like water leaking out of the system but very often because the water leaks back into the tank through the check valve.

Sailvayu's suggestion to watch the bilge pump or check your bilge for fresh water will probably confirm if the problem is the water leaking out of the system or an internal pressure drop.

[HopCar]

I would vote for bad valves in the pump. Leaks are usually pretty obvious. The bilge pump cycleing, dripping sound and dropping water level in the tank. Valves are the most common problem with water pressure pumps. What make and model of pump is it?