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Air in freshwater system

blackrose

By blackrose
in Boat Building & Maintenance

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Sea Dog Veteran II

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Posted
Posted (edited)

What is it about yours that means it needs to be installed in a certain direction?

Just a guess, but wouldn't it be best if the flow was in the direction that let's the sh.. collect in the mesh on the same side as the bit that comes off so you can take it away and flush it rather than there being any crud left in the fixed housing which is in an awkward place?

 

 

ETA that's not my apostrophe in 'lets', it's a bloomin' autocorrect! I'm leaving it in to try to shame it into doing better next time, or it'll never learn.

Edited by Sea Dog
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blackrose Veteran II

blackrose

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how much air is in the filter bowl? 50%? 20%? It's normal to have SOME.

Perhaps 30%. I called Mack Engineering who sold me the pump and they said the same thing. They'd expect to have a bit of air in the strainer and it shouldn't be an issue. Perhaps my accumulator is leaking but there's no dampness anywhere.

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mross Influencer

mross

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I can't remember, did you ever unscrew the top of the filter, did you inspect the 'O'-ring? I still wonder if that's where air is being drawn in? Ther's only the head of water from the tank when the pump is not running and maybe it doesn't lose water at all. My taps were farting and it was due to a leak on the pump but in my case the pump was leaking water.

Edited by mross
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blackrose Veteran II

blackrose

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I've not followed this thread closely. Have we ruled out the PRV admitting air?

I can't see how that could happen on a pressurised system?

I can't remember, did you ever unscrew the top of the filter, did you inspect the 'O'-ring? I still wonder if that's where air is being drawn in? Ther's only the head of water from the tank when the pump is not running and maybe it doesn't lose water at all. My taps were farting and it was due to a leak on the pump but in my case the pump was leaking water.

I got the top off the strainer (eventually) it was on really firmly, but I don't think there is an o-ring around the cap of the pumpguard strainer. I cleaned it out and applied some silicone grease to the threads.

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blackrose Veteran II

blackrose

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Me neither, but if it's getting air into it then it can't be perfectly sealed, surely?

Yes, but as the second post on this thread explained, the air in the system is unlikely to be getting in on the pressurised side of the system because were that the case I would hear the pump activating occasionally for no reason (which I don't even with the accumulator isolated)，and also if the leak were on the pressurised side then surely water would constantly be forced out and no air would be able to get in (unless the pump was switched off).

 

So the leak is much more likely be on the non-pressurised side of the system where it will not activate the pump. Trouble is I just can't find it. No damp areas anywhere from tank to pump. Perhaps the leak is so minor that air can get in but water can't get out?

I think it would be hard to miss, maybe that is why you have the problem. A few turns of PTFE tape may be a bodge to get it working OK.

Thanks. I'm away at the moment but it's first job on the list when I get back.

Edited by blackrose
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blackrose Veteran II

blackrose

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I'm still living with this problem and contacted Mack Engineering who sold me the pump as I found a small leak from a tiny panel under the pressure switch. It's the one with the 2 screws in my picture below.

They agreed with me that since there's a lot of air getting into the system everyday but the water leak from the pump is quite small, the most likely cause is that the pump is sucking in air as it runs, but just drips slowly when it's not running. They said I'd probably be able to reseal the panel with some sealant, but I've run into problems as I can't get it off. It's just not coming out and now I've made the leak worse.

What's the panel for and do I need to take the entire pump head off to get the panel out? I've contacted Mack Engineering again today but I doubt they'll reply until next week.

Finally if I have to buy a new pump I won't be going for Jabsco again and won't go for Sureflow because they leak too. So are there any brands of 12v freshwater pumps that we know don't leak? I know mine is 5 years old but it's fared no better than my previous Sureflow which also lasted 5 years. It just seems to me that one of the prerequisites of good pump design is that they shouldn't leak - or am I expecting too much? Fortunately I didn't follow the advice of the bloke who sold me the pump over the phone when he laughed and said their pumps didn't need to be installed in washing up bowls (as I'd done previously with the Sureflow). Instead I used my own common sense, so at least I've had no water over the floor and in the bilges.

 

The small panel that's leaking isn't mentioned in the Jabsco service instructions: https://www.jabscoshop.com/files/Service%20PAR-MAX%2031xxx%20and%20Flojet%20Quad%20.pdf

post-1046-0-19837700-1483787224_thumb.jpg

Edited by blackrose
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blackrose Veteran II

blackrose

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Is it really a separate panel? I can't be sure from the photo. I doubt you'll find better pumps than Jabsco and Shurflo. I think you've been unlucky. I would buy a direct replacement and fix this one as a spare.

 

I'm not sure if it's a separate panel or not, but if not then why have it at all?

 

The exploded diagram on p3 of this document suggests it's not removable, but then what's it for and why's it leaking?

 

attachicon.gifPar Max 3 - 4 Water Pump.pdf

 

Perhaps I have been unlucky with this Parmax pump, but I disagree with you about Shurflo. I've read enough posts and threads on this forum over the past 10 years about leaking Shurflow pumps for me to be pretty Shur about that. They have a fairly bad reputation.

 

The Parmax 3 has been discontinued so there is no direct replacement, but I suppose I could buy a Parmax 4.

Edited by blackrose
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ditchcrawler Veteran II

ditchcrawlerDonate to Canal World

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I'm not sure if it's a separate panel or not, but if not then why have it at all?

 

The exploded diagram on p3 of this document suggests it's not removable, but then what's it for and why's it leaking?

 

attachicon.gifPar Max 3 - 4 Water Pump.pdf

 

Perhaps I have been unlucky with this Parmax pump, but I disagree with you about Shurflo. I've read enough posts and threads on this forum over the past 10 years about leaking Shurflow pumps for me to be pretty Shur about that. They have a fairly bad reputation.

 

The Parmax 3 has been discontinued so there is no direct replacement, but I suppose I could buy a Parmax 4.

Maybe its there specifically to leak if the diaphragm leaks into the body or even ventilating the back of the diaphragm so there is no pressure to inhibit it flexing

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mross Influencer

mross

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The Parmax 3 has been discontinued so there is no direct replacement, but I suppose I could buy a Parmax 4.

My Shurflo leaked but I don't know how old it was. I replaced it with a Jabsco which is easier to fit. I see there is a thread on pumps just started that recommends Whale pressure pumps (not Gulpers).

 

I was going to repair the Shurflo but spares are expensive. I bought a Jabsco just by chance.

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Drayke Rising Star

Drayke

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I'm still living with this problem and contacted Mack Engineering who sold me the pump as I found a small leak from a tiny panel under the pressure switch. It's the one with the 2 screws in my picture below.

 

They agreed with me that since there's a lot of air getting into the system everyday but the water leak from the pump is quite small, the most likely cause is that the pump is sucking in air as it runs, but just drips slowly when it's not running. They said I'd probably be able to reseal the panel with some sealant, but I've run into problems as I can't get it off. It's just not coming out and now I've made the leak worse.

 

What's the panel for and do I need to take the entire pump head off to get the panel out? I've contacted Mack Engineering again today but I doubt they'll reply until next week.

 

Finally if I have to buy a new pump I won't be going for Jabsco again and won't go for Sureflow because they leak too. So are there any brands of 12v freshwater pumps that we know don't leak? I know mine is 5 years old but it's fared no better than my previous Sureflow which also lasted 5 years. It just seems to me that one of the prerequisites of good pump design is that they shouldn't leak - or am I expecting too much? Fortunately I didn't follow the advice of the bloke who sold me the pump over the phone when he laughed and said their pumps didn't need to be installed in washing up bowls (as I'd done previously with the Sureflow). Instead I used my own common sense, so at least I've had no water over the floor and in the bilges.

 

The small panel that's leaking isn't mentioned in the Jabsco service instructions: https://www.jabscoshop.com/files/Service%20PAR-MAX%2031xxx%20and%20Flojet%20Quad%20.pdf

If you are trying to take this panel off it looks like you need to undo the four bolts that hold it on, and not the two screws that are in your picture, after taking the pressure switch and wiring off, at least that’s what it looks like on page three.

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blackrose Veteran II

blackrose

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If you are trying to take this panel off it looks like you need to undo the four bolts that hold it on, and not the two screws that are in your picture, after taking the pressure switch and wiring off, at least thats what it looks like on page three.

But in the exploded diagram on p3 the panel isn't shown separately from the housing so how do we know which way it's removed - or if it can be removed at all?

Edited by blackrose
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blackrose Veteran II

blackrose

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I could take the pump head off today and have another go at sealing the leak. The problem is if I make a mess of it then I'll have no water at all. I'm back a work tomorrow and will need a water pump this week until I can get hold of another one, so perhaps it's better to buy a new one, then fix this one at my leisure and keep it as a spare.

 

My only qualm about buying another Jabsco is that if they only last as long as any other pump then what's the point of paying nearly twice the price for it?

Edited by blackrose
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