Pressure water system won’t hold pressure, runs continuously

[chuck g]

My pressure-water system is running continuously and won’t hold pressure after being shut off. I’ve checked the discharge side of the pump and connections to my two faucets as well as my inline filter before the pump, but everything seems ok. I also bypassed the accumulator tank bit that didn’t help.

I have a two-year-old Johnson Aqua Jet WPS 4.0 gpm water pump and a Jabsco 30573 accumulator tank. Suggestions greatly appreciated —

I’ve posted a video at https://youtu.be/oIKaJCGaDI8

[travellerw]

Check your motor bilge. Its not uncommon for the water heater heat exchanger to fail. Depending on how it fails, means that your fresh water will be pushed into your engines heat exchanger (on the fresh water side). It will then be pushed through the overflow and run into the bilge.

[chuck g]

Hadn’t considered that possibility, thanks — my bilge has been accumulating some water for no apparent reason. How would I determine if the water heater has indeed failed and is the source of the problem?

[travellerw]

Originally Posted by chuck g

Hadn’t considered that possibility, thanks — my bilge has been accumulating some water for no apparent reason. How would I determine if the water heater has indeed failed and is the source of the problem?

The best way would be to isolate it. My hot water heater has the ability to turn 2 valves and its completely isolated from the house water circuit. If you isolate it and the system retains pressure, then you can be pretty sure that is your problem.

NOW, you need to be careful. If it has indeed failed and your motor has "coolant" then you risk contaminating your water supply with coolant.

If it has failed, then you can replace it, or simply remove it.

[Panacea2183]

Cap off the output after the accumulater tank (that feeds the rest of the system)
If it still cycles the “leak” is in the pump check valve.

If no cycling, then you have a leak in the system somewhere else.
Can be PITA to find, ask me how I know!

Patience and a lot of digging around, you will find the leak.

[chuck g]

Thanks for the wise suggestion; it still cycles when capped off. Now I need to figure out if I can replace the pressure valve or just need to replace the pump.

[Panacea2183]

Originally Posted by chuck g

Thanks for the wise suggestion; it still cycles when capped off. Now I need to figure out if I can replace the pressure valve or just need to replace the pump.

You can install a check valve or get a kit to rebuild the pump.
Check prices in your area.
My experience has been the cost to rebuild is almost as much as a new pump.
If the internal valve is bad, the rest of the pump is not far behind.

First disassemble and check for calcium or mineral deposits, you may be able to salvage it for no cost.

I carry many spare parts. After looking at kit prices, I just carry an entire pump Assy.

Most of it depends on where you cruise. In my case (remote areas) can’t afford to take a chance.

Good luck and apply cruising!

[CaptFigmo]

My pump cycles on once in a blue moon moon.
Can't find the source. Traced every line. Dry everywhere.
Driving me crazy!

[Chalifour]

Had a similar problem, not so easy to resolve. In our case was a lost of pressure somewhere in our pipes. Problem solved by replacing some plastic taps that seemed loose by age and cleaning the water system and pipes to eliminate particules that would have affected the tightness of some connectors/taps.
Good luck!

[SkipMark]

Originally Posted by CaptFigmo

My pump cycles on once in a blue moon moon.
Can't find the source. Traced every line. Dry everywhere.
Driving me crazy!

If you don't have an expansion tank in the freshwater system, then the hot water will cool when the engine has not run for a while, and the pressure will fall just enough to turn on the pump for a second or two.

[MJH]

Originally Posted by chuck g

My pressure-water system is running continuously and won’t hold pressure after being shut off. I’ve checked the discharge side of the pump and connections to my two faucets as well as my inline filter before the pump, but everything seems ok. I also bypassed the accumulator tank bit that didn’t help.

I have a two-year-old Johnson Aqua Jet WPS 4.0 gpm water pump and a Jabsco 30573 accumulator tank. Suggestions greatly appreciated —

I’ve posted a video at https://youtu.be/oIKaJCGaDI8

You don't say how old the pump is? More problems possible with an old pump.

Do you have a manual faucet to the same fresh water line? If so, insure the manual pump has been primed...I must do this every spring to get my system working properly.

Totally isolate the pump (possibly remove it to your work bench) and see if the problem continues. If not you have a leak somewhere.

Good luck.

~ ~ _/) ~ ~ MJH

[jrbogie]

Originally Posted by chuck g

My pressure-water system is running continuously and won’t hold pressure after being shut off. I’ve checked the discharge side of the pump and connections to my two faucets as well as my inline filter before the pump, but everything seems ok. I also bypassed the accumulator tank bit that didn’t help.

I have a two-year-old Johnson Aqua Jet WPS 4.0 gpm water pump and a Jabsco 30573 accumulator tank. Suggestions greatly appreciated —

I’ve posted a video at https://youtu.be/oIKaJCGaDI8

could be an air leak on the input side of the water pump.

[dbcape]

This is a common problem. If any debris gets caught in the diaphragm valves of the pump, the pump will not develop sufficient pressure to shut off.
Remove the suction hose then reposition the discharge hose onto the inlet. It there is any pressure on the discharge (pressurized) side, it may be sufficient to flush out the valves; then reconnect the hoses. Or if you have access to water on a pier, you can use a hose to flush the pump out. It's easy to try and it worked for me!

[Kenomac]

Air lock cavitation.

[Dave22q]

Similar problem drove me nuts for over a year. Finally I rigged a short hose with one end plugged. Started at the pump outflow which ruled out pump or upstream issues, then blocked flow to heater thus isolating cold vs. hot water lines and connections, etc. Inside of an hour I found my problem, loose hose connection to heater.
I guess it sounds a little complicated but it will always work as no guessing is involved.