Water pump pulses on and off

[Canuck27]

On my 2019 27 OB, the water pump comes on for maybe 1-2 seconds, and this occurs every 60 -90 minutes while we are cruising or tied to the dock. Don’t have any leaks in the water system. What should I be checking. Thanks

 

[S@LTD]

I had a similar problem where it would pulse every 10.15 seconds or so. Drove me crazy. I pulled the filter out of the pump, clean it and gave the cap an extra quarter turn when I put it back together. Now it pulsed once every 25 seconds. Going for the simple items first I pulled the O ring off the fill cap. While there was some cracking it didn’t look too bad. Replaced it anyway. Voila!! Not sure if this is your issue or not. Hopefully it’s something simple.

 

[Hamster]

I have found that air gets into the system when you drain it. I run all faucets and then open the pressure relief valve on the hot water tank for maybe 30 seconds. Seems to work. I also replaced the water pump and know others have installed an accumulator tank. Finally, just turn the pump switch off when not using.

 

[Canuck27]

Thanks for the quick replies and ideas. Will start the troubleshooting.

 

[Jared Dunning]

If your fresh water pump is going off every 60 to 90 minutes and for a short burst then that means you have small leak at one of the connections or faucets. You can also check for air by opening all the faucets and the shower system in the cockpit to release any air that could be in the system, but more likely than not you've have a small leak in the system.

 

[gregc]

If your fresh water pump is going off every 60 to 90 minutes and for a short burst then that means you have small leak at one of the connections or faucets. You can also check for air by opening all the faucets and the shower system in the cockpit to release any air that could be in the system, but more likely than not you've have a small leak in the system.

Huh, ok. My 27-OB has the same (every hour our so) quick burst of pump activity.

Any recommendations on how to track a leak like this? There is no obvious leaking at the faucets.

 

[Brian98133]

If there is no obvious leak (no water in bilge, no wetness at connections, no faucet dripping, etc., the only place the pressure can be going is back out the way it came in.

Our systems have a one-way check valve located between the water pump's impeller and the fresh water holding tank. Typically, they are part of the pump itself, located on the inlet side of the pump. These check valves keep the pressure that the impeller builds into the system from bleeding back into the holding tank.

Once enough pressure pushes backwards through a faulty check valve, the pump senses the drop in pressure and re-pressurizes. No water is being lost, hence the difficulty in finding an outward leak... because the pressurized water is simply going back to the holding tank.

Unfortunately, I personally don't know if these check valves are a replaceable item on the pump... I would imagine it would be, but I can't speak to that. But many times, the check valve consists of a rubber diaphragm that sits against a 'cage'. If sediment gets lodged in the cage, the rubber diaphragm can't sit properly, and water can push past it. So, it might be more of a 'cleaning' situation instead of replacement. Taking the pump out and trying to flush the inlet port out would be my first option.

 

[PanaSeaAh]

I found very small bits of plastic in the check valves. Couldn't find a replacement head for the pump, but opened it up easily picked out the pieces of plastic with a pair of tweezers, Reassembled and worked fine. This is not a new problem, and apparently was worse on older models without strainers on the line coming to the pump. A pulse once an hour and no visible leak would lead me to think it is the leak back through the check(s). It would be worse than that before I would tear it down.