Fresh water pump won’t shut off

GMSLITHO

I don't even have a strainer on mine goes from the tank straight to the pump 

raybo3

Is there anyway you can by-pass the filter? Come straight off the tank and see what happens.

raybo3

BTW how is the water pressure at the faucets?

Dream_Inn

it sure looks like there is an o-ring in that picture on it.  There definitely should be one on the part that slides in.

It looks the same as this one:

https://www.keoghsmarine.com.au/jabsco-pump-guard-strainer-plug-in-with-offset-20mm-hose-barb-46400-0010-j21-108

Are you sure it's not pushed in all the way?  They should be pretty snug after that blue slide is on it.

reneechris14

Looks like the second o-ring is missing on the strainer in reference to dreams link. Is there a way you can cap off the blue line as a test to get the pump to pressurize??

Spyderweb

@raybo3 I guess i’d have to come up with some more fittings to bypass strainer, but that might eliminate the air leak potential.  Water pressure at faucets seems normal.

@Dream_Inn those are just plastic barbs.  Seems there should be o-ring there or in pump.  Neither old nor new pump had one nor strainer.

@reneechris14 I unscrewed blue line, tightly held damp chamois onto pump outlet.  Had wife turn on pump.  I was able to hold chamois tight enough so no water dripped out at all.  Pump ran and did not shut off.  I loosened chamois just to check and water sprayed all over.  Tightened up so it would stop.  Pump just kept running.  I would say from that experiment, water leak or not, she’s not shutting off.

DanD2

If the old pump kept running, and the new pump keeps running, it tells me that you have air coming in somewhere's  between the pump and the water tank.

raybo3

@Spyderweb if you blocked off the discharge side tight and the pump did not shut off then that would tell me that the problem is on the suction side of the pump. Is there a check valve in the system? Maybe its not holding. Is your tank filling up when on shore water?

Spyderweb

@DanD2 that's the water tank to the left of my hand in the picture, so air leak is either at tank or strainer.  My bet would be strainer.  

Spyderweb

@raybo3 never used shore water system.  

Spyderweb

Have turned problem over to marina.  Service manager said they would be looking at it today.  

raybo3

@Spyderweb you know you could try putting the water hose in the fill and let it run and over fill the tank then look for a leak on the tank side. Just a thought.....

Spyderweb

@raybo3 I did fill the water tank full several times till it overflowed out the air vent.  Didn't notice anything different.

raybo3

@Spyderweb please keep us posted on what the marina finds. Seems like a strange problem. 

MarkB

This is definitely confusing, and I don't blame you if you were going a little crazy trying to resolve this. 

Here are the facts ... that pump SHOULD stop once there is enough pressure on the discharge side.  Given you replaced the pump ... and there is low probability the pressure switch has failed on two pumps (which is not impossible, just unlikely), I'd say something is preventing that pump from reaching the pressure needed for it to switch off.

Just trying to put my engineering hat on ... it's possible if there is a suction side leak, and you are drawing air in, the pump is not holding discharge side pressure. But here's another thing ... is there a non-return valve on the suction side of the pump ... this would ensure water can go back from the pump casing into the tank.  If that did happen, the pressure on the discharge side would build once you closed your faucet, and then just push back into the tank via the suction line.  Pump would just keep spinning around because it couldn't generate the pressure to switch off.

My mind says it's something on the suction side ... either an air leak or a faulty non-return valve.

Spyderweb

@MarkB It would seem these pumps would have to have a non-return valve or pump would always be trying to build up pressure in tank.  New pump is the identical model it replaced and that worked all last year.  

I too am leaning towards a suction side issue.  Do you know if there should be a gasket between the strainer and pump inlet?  if there's an inlet side leak, that's the likely spot.

Spyderweb

Been researching the Jabsco Flojet strainer with the "direct plug in quad port outlet".  It appears it is supposed to have an O-ring, part number FJ 20381- B (or E).  

https://www.pumpvendor.com/Flojet_Port_Fittings.html

Marina didn't get to boat today, but I passed this info onto him.

DanD2

I won't be able to get to my boat until the weekend. If nothing changes between now and then, I'll pull mine apart and take some pics for you.

Spyderweb

Thanks.

Ian

I agree, I think you are sucking in air and so it won’t pressurize. When I drain tank to winterize I let the pump empty it and when it gets low and starts to suck in air - you hear the pump whine and faucets spit - I shut faucets. But the pump still runs trying to pressurize, sucking in air. Then I shut it off.

Stodge

I see what appears to be an O ring in your picture on the part that goes into the pump.  

Spyderweb

@Stodge you know, I was looking at that picture yesterday, and comparing it to a picture online of a replacement, and I thought the same thing.  I took the strainer off my pump Tuesday specifically to look for an o ring and it all felt like hard plastic.  Granted I was in the bilge, so light maybe not the best.  So if it is an o ring, perhaps it's turned hard, or used up and needs a new plump one.  I sure hope so.  Running out of ideas.

MarkB

Spyderweb said:

Been researching the Jabsco Flojet strainer with the "direct plug in quad port outlet".  It appears it is supposed to have an O-ring, part number FJ 20381- B (or E).  

https://www.pumpvendor.com/Flojet_Port_Fittings.html

Marina didn't get to boat today, but I passed this info onto him.

I'd say it should have an o-ring, as the picture shows.  It should not spin around like you stated, it should be firm, tight.  I'm concerned maybe the hose clamp was overtightened and cracked the plastic ... probably the main reason to have an o-ring, to enable a seal without having to overtighten.

Spyderweb

@MarkB Yes, with pump running (line pressurized) I'm still able to rotate strainer easily, given limits of inlet hose to strainer.  There actually is no hose clamp to tighten to potentially crack plastic.  It appears it's called a  "direct plug in quad port outlet".  You just place male end of strainer into female end up pump (1st photo) and slide blue lever up to lock it in place.  Both inlet and outlet end of this pump have that connector system.  

MarkB

Ah okay I got you, I thought you were saying it could twist where that white suction hose is secured to it via the hose clamp in the picture above.  

I'm still thinking you have a suction side leak somewhere. Maybe the o-ring in that quick connect is the issue.

I think one way to check is to watch the water in that strainer site glass. If there's no break/leak, then it should stay full of water ... if it drains back into the tank, it means there's an air leak.  To do this, the water level in the tank needs to be slightly below the strainer level.

rmrstlmo

There is adjustment screw for the pressure switch inside the blue plastic cover.  My pump would not shut off last week.  I turned the adjustment screw 1.5 turns CCW and that was enough to make the pump operate properly.   I also couldn't find a leak and thought maybe the pressure switch is going bad so I purchased a new pump to have on hand.

Spyderweb

@rmrstlmo is that the tiny screw that looks like it takes a tiny Allen wrench to turn?

rmrstlmo

I believe mine was a Philips head.  I have the same 2.9 pump.  Can't imagine that would be different.

Spyderweb

I took my original pump apart (same model as new one) on the bottom.  Seems like there was one small Phillips screw holding blue cover on.  Then there were 2 larger Phillips screws holding what I assume was the pressure switch, basically a spring.  Somewhere in there, I believe under the blue cover was a tiny screw, that looked like it would take a tiny Allen wrench to adjust.  Is any of this familiar?

Spyderweb

Back to boat.   Tiny set screw is outside of blue cap.  Don’t know what it’s for.   However underneath blue cap is the pressure adjustment screw just as @rmrstlmo describes.  Backed off screw a couple turns and pump shut off 3 seconds then came on for about 3 seconds, then off and continued at that rate.  What I heard during each 3 second off period was a whoosh coming from inside the water heater.  As if an air leak and quick depressurization.  

I see no water leak from heater.  Seems like any compromise in water heater would produce water leak.  Dock mate suggested that was air in water tank.  Said to hook up to shore water and run water longer time to fully bleed system.  Am trying that now.  Did 10 minutes with all faucets open.  went back to pump and it went back to on/off again every 3 seconds.

I am running system on shore water again for longer period to see if it makes a difference.