Fresh water pump inop?

[Seevee]

All,


Trying to trouble shoot a fresh water pump. It's a Jabsco PARMAX 3.


It's suppose to run until it builds up pressure in the accumulator and shut off unless someone turns on a faucet. Right now it runs non stop.


That indicates to me that:
1. There is a break in a line somewhere and it's pumping water somewhere. Have checked and find none.
2. There's something wrong with the pump.


What else and any ideas on how to troubleshoot.


Thx

 

[DavidM]

The pressure switch isn't opening assuming the pump is pumping and building up pressure.

Some pressure switches can be adjusted for a lower pressure cut off. If it is adjusted all of the way or doesn't have any adjustment, then replace it.

David

 

[Seevee]

David,


Where would the pressure switch be? Part of the pump... on the accumulator?


Thx.


Bet it's easy to replace.


Thx

 

[Pack Mule]

I think it’s on top of the pump. Mine has stuck before . All I did was remove screws from switch looked at it and screwed switch back on. I don’t think I had to adjust it .

 

[ScottC]

If it's not the pressure switch, then perhaps it's a damaged diaphragm? The diaphragm might be good enough to supply some water when you open a faucet, but not good enough to build up any pressure in an accumulator. Just a wild guess...

 

[caltexflanc]

https://www.manualslib.com/manual/1327903/Jabsco-31395-0092.html?page=4#manual

 

[Bacchus]

Look it up / search online and include the series #.
Some have replaceable pressure switches some not.
I had a slightly different one that P Sw was no longer available. Worth a check bit I had to just replace the pump.

 

[bayview]

Bleed air from every faucet.

 

[Shrew]

If I recall the Parmax line has a built-in accumulator tank feature. I believe I have the same model. I hate it. I mean I HATE IT!!!!!

I constantly have issues with it. It will fail to pressurize fully, then run very, very slowly for hours until it overheats and shuts down. I've found I have to shut off the breaker, then wait 1-2 minutes, then power it back on to get it to pressurize correctly. This tells me that it isn't an actually pressure issue. It's the pressure switch which is faulty.

I'm replacing it with a normal pump and an actual external accumulator tank.

 

[Shrew]

The other thing I hate about it is the 'variable speed pump' which seems to want to 'negotiate' the water pressure. When I take a shower, the water pressure is great, then slowly decreases. I increase the water via the mixing valve, then it slowly decreases again. I'm constantly in a fight for water pressure. The variable speed pump feature is annoying. I can handle variable water pressure with the mixing valve, I don't need the pump to tell me how much water pressure I think I need.

 

[JohnEasley]

My friend's boat had a similar problem. They no longer sold the pressure switch as a separate component for his model but they did sell the entire head assembly. He replaced it and everything is back to normal.

 

[Seevee]

Update on the water pump.


I replaced the Jabsco Parmax 3 with a Parmax 4.


Before I did, I replaced the plumbing (SeaTech which is now Aqua Lock) from the pump to the accumulator. Also, precharged the accumulator with air to 41psi (mfg rec). (Does anyone use nitrogen for the precharge.... believe I will next time I have my nitrogen tank handy).



Everything works reasonably well and the water flow is better than ever. However, it builds up the pressure stops, and a few minutes laster turns on again and cycles for a bit and stops.



When is does this, I'm listening and watching close to the pump and accumulator. Just before it turns on again, I hear a slight gurgle and hiss coming from the accumulator. WTF?


Is this characteristic of air in the lines? It should just build up the pressure, stop and only start again when water is used.


Baffled...

 

[Solly]

Gurgle and hiss sounds like air escaping somewhere. Accumulator might be shot. Try bypassing it and see what happens.

 

[ScottC]

Should only turn on again after a bit of water is used.
Check that the schrader valve on the tank is screwed in tightly. You might need a special "wrench" for this from a car or bicycle tire gauge that happens to have such a wrench at the end of the gauge.


An easy way to check is put a glob of dishsoap/water over the schrader valve and see if it bubbles.

 

[caltexflanc]

41psi sounds awfully high for accumulator pressure on a boat. Typically you want it just under the cut-in pressure for the pump, usually somewhere in the 20's on a boat. An in-line pressure gauge is mighty handy. Was the accumulator pressure spec in the pump manual or the accumulator tank manual?

 

[Seevee]

41psi sounds awfully high for accumulator pressure on a boat. Typically you want it just under the cut-in pressure for the pump, usually somewhere in the 20's on a boat. An in-line pressure gauge is mighty handy. Was the accumulator pressure spec in the pump manual or the accumulator tank manual?

The pressure was from Jabsco tech guy. Will double check... agreed, sounds high.


Will also check the accumulator to see if its leaking.


Thanks

 

[Comodave]

I also think 41 is high. Check the pressure where the pump cuts out and maybe try that. Also sounds like you have a leak by the accumulator. I had a pump that had a valve bad and water would backflow and the pump would burp every now and then. But you have a new pump so it is probably the accumulator.

 

[caltexflanc]

The accumulator pressure needs to be just a couple PSI below where the pump is set to cut in, that is, turn on. It's possible the bladder got blown out by high pressure or old age.

 

[Swfla]

You can check to see if the accumulator tank is shot. There's an air bladder inside it. If it gets a leak in the bladder, water starts to collect inside the tank. Turn off the pump power and and turn on a faucet to get zero water pressure, remove the tank, it should just unscrew. If water comes out or you hear water when you give the tank a shake, it's shot.

 

[bill.kimbell]

Often an air leak at the strainer...sometimes cracked, sometimes bad O-ring. Try the simple stuff first.

 

[panhead56]

Good morning, our Jabsco water pump model #31750-0000 (3.7GPM) needs to be replaced.
Having a hard time trying to find one in stock.
Left an email with the manufacturer hoping that they have a similar model replacement. Really do not want to re-plumb the piping.
Was wondering which model that you went with. Did you have to redo the plumbing with the replacement pump?
Thank you,
Gary
Mainship 34T 2009

 

[OldDan1943]

Good morning, our Jabsco water pump model #31750-0000 (3.7GPM) needs to be replaced.
Having a hard time trying to find one in stock.
Left an email with the manufacturer hoping that they have a similar model replacement. Really do not want to re-plumb the piping.
Was wondering which model that you went with. Did you have to redo the plumbing with the replacement pump?
Thank you,
Gary
Mainship 34T 2009

Have you tried West Marine?
It may be in their warehouse.
Word of advice, always carry a spare. WINK

 

[panhead56]

I have tried West Marine and many other locations. Apparently it is discontinued/not in stock. I did receive a reply from a local pump supplier. They have a recommended replacement, but the GPM is 5.0. My existing pump is 3.7GPM.
I’m concerned that my existing fittings/connections might not be able to handle the higher GPM?
Here is the recommended replacement pumps; “Good morning Gary,

Thank you for the enquiry. Unfortunately, this model is no longer available I can offer a different option. Please see below.

Jabsco 42755-0092 (12v, vflo 5.0 gpm) your cost:$314.30 each. in stock.
Jabsco 31395-0092 (12v, parmax 2.9 gpm,25/45 psi) your cost:$109.25 each. in stock.
Flojet R3526144 (12v,2.9 gpm, 50psi) your cost:$143.91 each. non-stock. lead time (3-4) weeks.

 

[OldDan1943]

Gary, I suspect your current hoses and fittings will enjoy the extra pressure.
Of course, with higher pressure you may discover increased water usage.

 

[panhead56]

Looks like I will be purchasing the replacement model. I was reading the manual. I’m not sure if I have an accumulator tank on our 2009 Mainship 34T. I’m not at the boat but I never remember seeing one.
I attached a photo showing my existing pump. Looks like a pressure switch was added to the pump? Not sure if the new pump has the sensor on the supply side?

 

[menzies]

Looks like I will be purchasing the replacement model. I was reading the manual. I’m not sure if I have an accumulator tank on our 2009 Mainship 34T. I’m not at the boat but I never remember seeing one.
I attached a photo showing my existing pump. Looks like a pressure switch was added to the pump? Not sure if the new pump has the sensor on the supply side?

When you turn on a faucet does your water pump always run immediately? If so you do not have an accumulator.

 

[skindiver]

Fresh water pump

Panhead56
I have a 2008 34T and have had both fresh water and saltwater pumps go out. The fresh water pump is a 31750-0000 and it has the same little black box in line with the fuse that you show in your photo. I am looking to change it to a 4 or 5 gpm model. The current one in sucking air all the time. The lines are good.

The saltwater pump was the same Jabsco model, but I replaced it with a 82505-0092. It is 5 gpm but is 70 psi. Too high for the fresh water system.

The new Jabsco washdown pump did not come with the extra little black box.
Good Luck and smooth cruising.

 

[Duetto]

i believe that you can buy different pressure switches from places like pump-vendor

 

[Seevee]

Should have posted a final solution to my issue.
Replace the pump with a Jabsco ParMax 4, PN 31620-0092 $187.09 with my marine disc. (retail 239.40)

Replace the accumulator with new one, Jabsco 30573-0000. $68.32 Amazon.

Put new o-rings (actually just replaced some of the plumbing fixtures (have the 15mm pipe).
Charged the accumulator to 17pis (NOT 41... don't know where I got that number).


Works great.


Panhead Gary,


Would suspect that the same exact thing would work for you as our boats are VERY similar... just be sure you size the pipe correctly...mm or inches.

 

[panhead56]

Sorry...I wrote a reply the other day, but unfortunately the entire message was lost.

I contacted the manufacturer and asked for a replacement for my old pump hoping not to adjust/mess with the existing fittings.
Jabsco recommended the “Variable flow Jabsco VFLO 5.0 GPM Automatic Water Pressure Pump”. Defender Marine had them in stock.
I was pleasantly surprised that both hose attachments lined up. The mounting hole were different but not a problem.

The existing in-line fuse wires were way under sized. I was surprised but might have been installed by the P.O.
I replaced the in-line fuse wire with correct gauge and a 15amp fuse.

We do notice the extra pressure, going from 4.0 GPM to 5.0 GPM. Especially while using the head. Hopefully the water tank level will not drop too fast.

Skindiver, When I was connecting the wires. I noticed that next to the power supply for the fresh water pump. There are two other wires that were capped off for future use. I’m thinking that these wires were for a raw water pump, which my boat does not have. There is spare circuit breaker on the panel for a raw water pump. If I ever wanted a raw water pump I guess that I would have to add another strainer thru the hull.

Thank you for all the help and suggestions!