Water pump keeps running on Mainship 390 for no reason

Paul Baker · 09-16-2018, 05:59 PM

My water pump keeps kicking on every 20 minutes or so for about 3 seconds.
The manual states this indicates a leak. There's not much to check. The forward and aft shower's. The bathroom sink and shower. The water heater. I don't see anything. I live in the Fort Lauderdale area and have been very disappointed whenever I have needed work done (Besides Wards Electric). Does anybody know somebody good in the area?

psneeld · 09-16-2018, 06:27 PM

If no leaks...and they can literally be a few drops...

Then many times it is internal bypass within the pump. If that, you can rebuild or replace the pump end or the whole pump.

Every 20 minutes isn't bad unless it wakes you up. It might stay like that for many months if you can stand it.

Xsbank · 09-16-2018, 07:48 PM

Shut it off until you need it?

O C Diver · 09-16-2018, 08:22 PM

If you have a pressure tank, check the bladder air pressure. Loss of air in the bladder may be making the pump short cycle. You still have a leak to find, but most pumps with pressure tanks run for more than 3 seconds.

Ted

wkearney99 · 09-16-2018, 08:27 PM

What make/model pump is it? Most will have a pressure switch of sorts that detects when pressure drops and will run the pump accordingly. If that switch is broken it'll cause the pump to run. But there's a ton of places where something can leak.

What kind of piping is in the boat? The push-fit Whale style? Might be an easy way to check the pump by stubbing off the out side with a valve. That'd narrow it down, right quick.

motion30 · 09-17-2018, 05:53 AM

I bet it's the jabsco pump. They tend to leak internally. I've had several and tried replacing the pressure switch with no avail. The final solution was to avoid jabsco products

High Wire · 09-17-2018, 06:04 AM

That run time indicates a steady dripping leak externally.
Check the water heater relief valve and all around the base of the water heater for dampness.
Is there any trail of water leaking into the bilge? Get a bright light and check everywhere there is plumbing, not just at the end equipment.
Also could be an internal pump check valve leak as mentioned above.
Do you not have a galley sink? Ice maker? Shower on the transom?

psneeld · 09-17-2018, 06:05 AM

Its not just Jabsco, I have had at least 4 different manufactures including Shuflo, Seaflo, Five Oceans...... forgot the other (s).....

Now whether they are all clones under different names....or have the same parts in the pump sections I cant say....

But the one or two second burps are often the inyernal bypass after completely sure you dont have a leak....including electric toilets, etc....

FF · 09-17-2018, 06:24 AM

Next O' nite or when you leave the boat, turn off the pump.

On return ,switch pump on and monitor, if its a system leak the pump will run for a while, if it an internal leak the run time will be short .

OldDan1943 · 09-17-2018, 06:25 AM

Hunt down the accumulator, try bleeding from the tire valve stem. If you immediately get water and no air, the accumulator has failed. Replace the accumulator If you get air, a few strokes with a hand pump to replace the pressure you bled off. Onward in your trouble shooting.

psneeld · 09-17-2018, 06:37 AM

Good advice FF.

Is there even an accumultor in the system?

The Other Gary · 09-17-2018, 08:58 AM

The most common cause of this is the internal check valve on the inlet side of the pump. Water leaks back into the tank past the check valve and the pump comes back on to build pressure. It can rive you crazy as it is a leak with no visible water loss at all.

RT Firefly · 09-17-2018, 09:13 AM

Greetings,
Mr. PB. Can't add anything to the good suggestions already posted BUT I am also looking for competent trades people in FLL. Many, many good businesses there with helpful and very competent counter staff BUT no field workers that are worth the extortion of $100+/hr rates charged. I don't mind high fees but please send someone, ANYONE who knows which end of a screwdriver to use...

OldDan1943 · 09-17-2018, 10:04 AM

Quote:

Originally Posted by RT Firefly

Greetings,
Mr. PB. Can't add anything to the good suggestions already posted BUT I am also looking for competent trades people in FLL. Many, many good businesses there with helpful and very competent counter staff BUT no field workers that are worth the extortion of $100+/hr rates charged. I don't mind high fees but please send someone, ANYONE who knows which end of a screwdriver to use...

Where abouts in FL and what do you need done? I maybe able to recommend a few folks.

RT, you meant to say, "$100 PLUS"
I learned my lesson when it comes to 'shade-tree' mechanics and one boatyard.

High Wire · 09-17-2018, 11:28 AM

You can prove the check valve condition by immediately after it pumps up, close the tank outlet and remove the pump inlet hose. The water should drain out of the pump and stop. If it keeps draining then the check valve(s) are leaking.

Lepke · 09-17-2018, 12:55 PM

If no sink/shower leaks, it's the pump valves leaking. Water leaving the pump goes thru a check valve. The valve holds pressure for the whole system after the pump shuts off.
If the valve seal is bad, and it could be as simple as a piece of debris embedded in the seal, water will slowly leak back to the pump water source.

George Harmon · 09-17-2018, 12:56 PM

I had the same problem a few years back and found that all that was needed to stop the intermittent running was to snug-up all the hose clamps on the water lines from the pump downstream. Not sure which one was the culprit, but some did tighten significantly during the procedure.

Paul Baker · 09-17-2018, 03:54 PM

Quote:

Originally Posted by OldDan1943

Where abouts in FL and what do you need done? I maybe able to recommend a few folks.

RT, you meant to say, "$100 PLUS"
I learned my lesson when it comes to 'shade-tree' mechanics and one boatyard.

My boat is docked behind a private residence in Lauderdale Isles. I have a bilge pump that doesn't get all the water out. We plan on going to the Bahamas in January for 6 months or so, so I'm looking for someone to show me how to change impellers, do oil changes and change filters. Only had the boat since July. Whenever i have had someone to "fix" something they spend hours without rectifying the issue.

RT Firefly · 09-17-2018, 05:09 PM

Greetings,
Mr. PB. Do you have engine and/or equipment manuals? IF you can find a comfortable place to sit beside the engine or in the engine space, have the engine manual at hand as well as an inspection mirror and a GOOD source of light and imagine going through the steps to perform various service tasks.

If changing impellers, for example, what tools will you need? Is there anything in the way that has to be removed before you can change an impeller? Can you actually see and reach everything you have to? When you drop your wrench or a screw/nut/bolt, where will it end up? That sort of stuff.

High Wire · 09-17-2018, 05:40 PM

Quote:

Originally Posted by Paul Baker

My boat is docked behind a private residence in Lauderdale Isles. I have a bilge pump that doesn't get all the water out. We plan on going to the Bahamas in January for 6 months or so, so I'm looking for someone to show me how to change impellers, do oil changes and change filters. Only had the boat since July. Whenever i have had someone to "fix" something they spend hours without rectifying the issue.

Sounds like a shout out for help from a local TFer. Anyone in the neighborhood?