Drinking Water Pumps

[Sonosailor]

I was flushing the glycol out of my tanks last night, when my water pump failed again. I now have 5 Flo-Jet pumps all in a row that do not work. They are all the 4-piston type.

They all make the right noise, and some even pump up to an accumulator or pressure tank to give that great first burst at the tap. But they soon stop pumping. The noise continues, but the water slows to a trickle.

I've taken them apart, cleaned them, watched the pistons move under power, checked each diaphragm, reassembled; and still they work the same. They even have a slight positive head on the suction side.

I have gone through 4 pumps in two short Canadian seasons. They have not frozen, nor have they been used with tough service. The boat only has two sinks and a shower.

Granted, there was some grit/coral particles in the tank, but now I have a good filter catching that. No chance that the filter is holding back water.

Any ideas? Anybody experienced in fixing or renovating these pumps?

[delmarrey]

Have you considered going to a pressure system.

We go through those pumps in the big rigs here all the time. The problem is when they sit the rubber seats deform over time and they loose their ability to keep pressure. By installing an accumulator down stream from the pump it keeps pressure on the valve/piston seats, keeping them in shape and sealed. Plus you don't have that pulsating pumping action but a steady flow. You'll have to install faucets that shut off and keep the pressure just like at home. It's best to leave them on all the time.

There is the air pressure system also, using an air pump to create the pressure. The water tank is pressurized forcing the water out. But you would have to put in a tank built for pressure.

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[Sonosailor]

Thanks for the post. I have installed a small pressure/accumulator tank as you suggest, even though the pump manufacturer says not to use one. I do find it interesting that the manufacturer says not to use one instead of saying only one is not needed; and have considered trying these without a tank just to see if somehow the tank is part of the problem.

My logical mind tells me that there should be little damage and much gain to a tank, but I have missed the obvious in the past.

As for keeping the pressure on them, it makes sense, but hard to do during the off-season at my poorly chosen latitude.

[Alan Wheeler]

I also have one of these pumps. I have not had a problem so far. But I did fit a Tank. It made a world of difference. I couldn't understand what the manufacturer was on about in regards to some small hole somewhere in the valving, which eliminated the need for an accumulator. To me, the accumulator is saving the micro switch by reducing the on/off cycle of the switch. It has made a far better job at producing a constant flow of water, instead of the pulse of increase/reducing pressure, especially when through the shower. A tank is most definatly the way to go.
Hope a tank solves your problem, because they seem to be a great pump.
Wheels

[delmarrey]

As for shutting it down for the winter, I guess that's the price us northsman we have to pay (spring refits). If you were able to fill your system with a bio-antifreeze and start it up weekly, it would probably last a bit longer. Maybe a 12V timer to run for a couple hours a week. It maybe less $$ for a new pump with all the time ane efforts, but for a live-aboard an accumulator is the way to go.

As for the manufacturer, they want you to buy a new one every year (capitalism).

Alan, the small hole in the lines, if at the far end away from the pump, is actually using the lines and system as a mini accumulator by expansion and contraction of the lines. We do this with compressors on the paint rigs. A 100 foot of hose/piping can be used as a holding tank for short term blasts.

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[Alan Wheeler]

No, this is built into the pump. This is what the manual say's.

"The built-in bypass valve eliminates the need for an accumulator tank. Do not install in a system with an accumulator tank. The tank will interfere with the internal bypass valve."

Well I would have to say, fitting a tank was the best thing I did. So I am at a loss as to what the heck they are on about.

Just as an aside to Sonosailer, The manual also say's,
Failure to Prime:
1: Restricted intake or discharge line
2:Air leak in intake line
3ebris in pump
4:Punctured pump diaphragm
5:Crack in pump housing

Oh and why do you have glycol in the system? Is this to stop freezing?? You mean it can get THAT cold there???? Yikes you guy's need to move! So what about getting the glycol out of the system again? I mean, wouldn't it taint the water and isn't it poisonouse??
Wheels

[GordMay]

Sonosailor admits "...I have gone through 4 pumps in two short Canadian seasons..."
Perhaps you should reflect on Einstein's definition of insanity:
"Doing the same things over and over - and expecting differing results"

Now, I generally like Flojet products, but I've not used the "Quad Bypass".
Inb my ignorance of this specific product, I'd suggest that it's time to try something else.

Gord

[Sonosailor]

You'll always get what you always get.

Sage advice, Gord. I would have to go through the posts to find the reference to Quad Bypass. Both Flo-Jet and Jabsco (interesting that the company "ITT" has purchased both companies over the last year or so, and intends to keep both companies separate even though their pumps are the same) provide pumps with the basic 4-piston system which rattles diaphragms and moves the water along through a final diaphragm and past a pressure sensor on the high side. I also know nothing about a hole or bypass system. The sensor simply senses when the pressure above the pump drops, and turns the pump back on.

I'm going to pay more attention, and try to figure out what the problems are. I am going to purchase some "guts" for the pumps, set up a spare inlet and outlet and spare power sources, and play away.

I just got into the water, and Wednesday is my last day of work. With the launch, my stress has begun to drop. I have 3.5 months before the end of the hurricane season, and I will spend the time learning and enhancing the systems.

Alan, I know of no-one who is having as much trouble as me. Therefore you might be right about the quality of the product. I likely am suffering some combination of damage from sharp granules and bad luck. To the manufacturer's list of causes of suction problems, I would add "clogged filters". As for it being cold here, you bet. And I am moving. I'll be in the Carib by December 1, when the insurer says I can.

I use propylene glycol, also called RV antifreeze. Unlike the poisonous ethylene glycol which pokes huge holes in your liver, only one in a hundred are allergic to propylene glycol. Rinse, rinse, rinse, regardless. Canada is a great place for cross country, down hill, snow men, skating, and of course, hot tubs.

[svJasmine]

maybe?



Kinda like checking the gas tank before the tow truck comes.

[Greg B]

I had a similar problem and after much consternation I discovered an air leak in the suction side. Seems that when the pump was drawing a vacuum one fitting was allowing a minute amount of air to enter and eventually stop the pump but when the pump was off it would reseal itself and not leak. It was a bugger to find and I had actually begun replacing the line from tank to pump when I found it.

Been flawless since and we winterize here in MI too.

BUT NOT NO MORE!!!! YEEE HAAAA

Greg