Fresh Water Pump Running Constantly

[Lepke]

If the pressure switch is in the front of the pump, the contacts are probably stuck together from heat because of too many amps. The switch used in those types of pumps are simple micro switches, available everywhere. If you open the pump and inspect the switch, it's probably not rated for 12v DC, but manufacturers use them anyway. Usual rating is 125v DC or 120v AC. On Amazon or ebay, about $3-4 each. Search for pump micro switch.

[Howler]

Originally Posted by Cheechako

Sometimes it will not just get pushed out.. Especially if there is a loop UP in the tubing. Water flows through it, but it is still in that UP loop. It probably wold with more flow but these pumps dont really flow a bunch of water.
I had one boat that would do it every time if I let it run out of water. Needless to say I was careful to not be lazy and let that happen eventually.

It may come out with continued running of water from the highest faucet in the boat, although you should do all of them.
Do you have a stern shower? That's another culprit for accumulated air.
Otherwise see if you can find a significant UP loop somewhere, and disconnect to get it out or lower it down to allow air to flow further on etc.

I looked for up loops but there are none. Good idea though! Thanks!

[Howler]

Originally Posted by rslifkin

When you turn all of the faucets off, do you hear the pump load up and slow down? If so, it's either a small leak, or the pressure switch isn't shutting the pump off. If it's not loading up, there's either a big leak, or air somewhere that's preventing it from building pressure.

Yes, the pump changes speed with the faucets on/off. I'm going to get a piece of hose and a cap to attach to the pressurized (downstream) side to really test the pump before replacing it.

If the pump turns off in that situation, then the pump is OK and it points to a leak on the pressurized side. I'm not sure where to look next as there's no evidence of a leak anywhere downstream. Checked all the plumbing in, out and around the hot water heater, galley, head and stern shower. Everything is bone dry, as is the bilge.

[Howler]

Originally Posted by mvmojo

Odds are high that you have a faulty check valve in the input to the pump. Water is leaking back to the tank when the pump shuts off causing a loss of pressure which turns the pump back on. If the check valve is leaking a lot of water back into the tank, the pump will run continuously trying to keep pressure in the system. I'd start by taking the pump apart and looking for some trash on the check valve diaphragm(s).

Thanks. I dissected the pump but the check valves are all supple and clean. The pump is only two years old. Are there typically other check valves in the fresh water circuit upstream of the pump?

[Oeanda]

Originally Posted by Lepke

The switch used in those types of pumps are simple micro switches, available everywhere... On Amazon or ebay, about $3-4 each. Search for pump micro switch.

This was my experience. Dissected the pump, dug out the switch and googled the number printed on it. It was a refreshing change to avoid the marine price tag and fix our pump issue for only a couple dollars. I wish that stuff happened more often.

[Howler]

Problem solved! And don’t I feel like a fool. You all deserve a good laugh at my expense as gratitude for all the thoughtful postings.

Pump cycling constantly, water tank level going down faster than normal, no downstream leakage inside the boat or near any plumbing fixtures. Any? Well, not quite. This is a recent model Dufour and they offer a built-in grill and bar sink under the stern seats. I don’t usually think about that sink but I happened to open the seat when the water pump was on and guess what was running full blast? Yup, the bar sink, happily transferring fresh water back into the sea.

As soon as I turned it off, the pump stopped as expected.

So please laugh appropriately. I deserve it. But I learned a lot about plumbing systems and thank you for that!!

[GordMay]

Originally Posted by Howler

Problem solved! ...
... As soon as I turned it off, the pump stopped as expected...

Tradecraft 101:
PLUMBING
Water running: Turn off [close] tap.
Water not running: Turn on [open] tap.
ELECTRICAL
Appliance/device not working: Plug it in.

[rslifkin]

Originally Posted by Howler

Problem solved! And don’t I feel like a fool. You all deserve a good laugh at my expense as gratitude for all the thoughtful postings.

Pump cycling constantly, water tank level going down faster than normal, no downstream leakage inside the boat or near any plumbing fixtures. Any? Well, not quite. This is a recent model Dufour and they offer a built-in grill and bar sink under the stern seats. I don’t usually think about that sink but I happened to open the seat when the water pump was on and guess what was running full blast? Yup, the bar sink, happily transferring fresh water back into the sea.

As soon as I turned it off, the pump stopped as expected.

So please laugh appropriately. I deserve it. But I learned a lot about plumbing systems and thank you for that!!

Gotta love the solutions that are so simple you ignore it until you've ruled out everything else. Because that can't possibly be it...

[dfelsent]

For me, one interesting part of this saga is contained in the original post. “All faucets are off. “
I have done a lot of troubleshooting of complex systems, and spent a lot of time chasing things due to poor initial assumptions.

Easy to do.

Now, as step one with a head scratcher, I clearly lay out what I KNOW and what I think I know.

Once that is sorted the rest is easier.
Sometimes if you are stuck you have to repeat that initial step too.

[toda]

Originally Posted by Howler

The fresh water system on our two-year old boat has a Jabsco Par-Max 2.9 pump. It's worked fine so far, then just recently it began running constantly, unless I turn off power from the DC panel. The fresh water tank is full and the pump is delivering plenty of water pressure to the faucets. Only, when the faucets are all shut off, it doesn't stop running, as if the system wasn't pressurized. I checked for leaks and blockages up and downstream and there are none. I assume it's the pump that's malfunctioning. A Jabsco video shows how to clean the check valves to solve a non-priming problem. Could that also cause the above symptoms?

Any suggestions to troubleshoot this problem would be appreciated!

When this happens to my system I have found that the pressure tank has lost it's air. Over time the air in the pressure tank becomes saturated with water vapor and the bubble in the tank gets smaller and smaller. Solution: turn off the pump, and drain the pressure tank. Turn the pump back on and see if it builds pressure sufficiently to trigger the cut off switch. If not, as posted by others, could be a faulty pressure switch.

[Huggi21]

Originally Posted by Howler

The fresh water system on our two-year old boat has a Jabsco Par-Max 2.9 pump. It's worked fine so far, then just recently it began running constantly, unless I turn off power from the DC panel. The fresh water tank is full and the pump is delivering plenty of water pressure to the faucets. Only, when the faucets are all shut off, it doesn't stop running, as if the system wasn't pressurized. I checked for leaks and blockages up and downstream and there are none. I assume it's the pump that's malfunctioning. A Jabsco video shows how to clean the check valves to solve a non-priming problem. Could that also cause the above symptoms?

Any suggestions to troubleshoot this problem would be appreciated!

If you cant find any water leaks in the system The quickest and cheapest electrical fault finding method is too disconnect the 2 wires to the pressure switch first ,turn on the circuit and touch together ,if the pump runs then its almost sure its the pressure switch not working, if the pump dosen't run when wires are connected , probably the relay is faulty . This how i found out my relay was the issue ,nice easy fix for a change

[captainwd40]

I am typically reluctant to comment on this forum due to all the other experts here ...... but ..... in this case I will offer some advice since I experienced the same problem.

It would appear that there is some corrosion in the pressure switch relay. When this would happen to me, I would wrap the pressure sensor with a wrench 2 or 3 times and it would behave itself and shut off like it is supposed to.

Although a bit hard to get to on my boat, I removed the pressure sensor housing sprayed it real good with WD40 which solved the problem for about 3 months. Then it acted up again so I replaced the pressure switch and relay ..... and recommend you do the same.

Cheers!

[Dieseldude]

A pressure switch operated pump that runs continuously will be due to either a failure of the pressure switch or a number of causes of a failure to build up pressure. Pressure switches can fail due to build up of sediment in the tubing that connects to the pump chamber or outlet port, or sediment in the diaphragm chamber itself. A leak in these can also cause the problem, but leakage was not indicated in the description. Some pressure switches can be dismantled and cleaned and repaired. I have made diaphragms from gasket rubber that lasted a long time. If the pressure switch is a specific fit to the pump and an original type is not available, an external one can be plumbed and wired in.


If a pressure gauge is not already in the system, it would be a helpful troubleshooting aid to fit one. Also, a vacuum gauge on the suction side would be helpful.


Before doing any involved troubleshooting, it would be wise to check suction pipework and strainer for blockage. If the suction pipe has a check valve at the end inside the tank, this could be worn out or stuck open by debris. But if this were the problem, the pump should shut itself off normally, then start for no apparent reason after water back drains to the tank.



An internal check valve may be leaking water back to the suction side. It may be worn, damaged or obstructed by sediment or trash that got past the suction strainer, if there is one. A leak in the suction piping may not be noticed because air would get sucked in rather than forced out. Disconnecting the suction pipe and connecting a short hose and routing this to a bucket of water can assist in determining this. If the pump works normally with this arrangement, that means to start checking suction pipe work for leaks. With the pump disconnected, a valve, pressure gauge and air fitting can be temporarily fitted to the suction pipe. The pipe work can be pressurized with air and gauge watched. The ruggedness of the suction piping will determine how much to pressurize. If as sturdy as the discharge piping, the full pump pressure would be ok. If weaker, 15 psi would be the maximum. Suction vacuum can never reach more than 15 psi differential between internal and atmospheric at sea level.


A diaphragm pump should be self priming. So air in the suction line should not cause this problem. However, just to be thorough, a tee fitting with a valve can be placed next to the suction port. Open the valve and fill the suction line with water. Close the valve and start the pump. It could take a few attempts to dislodge any air.


The pressure side can be tested by disconnecting the system pipe and fitting a hose and routing this to a bucket. Start the pump and check for flow. If good flow, fit a valve and pressure gauge. Close the valve and start the pump. The pressure should rise quickly to normal, and pump should shut itself off. If it does not shut off immediately upon reaching normal pressure, shut it off manually to avoid over pressure and damage.


If the pump fails to build up pressure and the suction side tests ok,then the problem is most likely a failed internal check valve or the diaphragm has split or has a hole.

[Stu Jackson]

2 Things


1. Thx for your honesty. Glad you solved it.


2. Wish folks would read a thread before they post, even if their advice may have been helpful.

[Uncle Bob]

Originally Posted by Stu Jackson

2 Things


1. Thx for your honesty. Glad you solved it.


2. Wish folks would read a thread before they post, even if their advice may have been helpful.

+1