Fleck 5800 Piston rod replacement

[flynmoose]

Hey Fleck-heads,

Some neighbors and I did a group buy a few years ago from one of our friends here on the board. Fleck 5800 valves over twin stacked tanks with Katlox/Ferrilite for low iron/manganese. Units have been working great.

Since I did the research, comparison, ordering, and plumber hiring, I've now inherited the "dealer responsibility" to my neighbors.

One neighbor had a hot water leak a few months ago and was too lazy to call a plumber right away. Kept turning the house main on and off when he needed water. Finally got a plumber out and replaced his old tank with a new tankless.

All was well... except that his softener seemed to leak water down the backwash drain all the time. So... who gets the call? Not the plumber! ;-)

Anyway - long story short, I followed the very simple disassembly instructions for the 5800 figuring he had blown a seal or had a piece of grit stuck somewhere.

Was surprised to find that the piston rod "nub" at the end where it connects to the piston was sheared off. The leak was caused by the piston being in an "intermediate" position.

I suspect that in all of the water cycling on and off, he created a water hammer at some point that slammed on the piston and sheared off the nub.


1) Online suppliers sell the entire piston rod, seal cage, and cover assembly as a single unit for about $80. Certainly can go that route if deemed necessary or prudent but...
2) It appears the 5000Pro piston rod is identical and it is sold as a single piece for about $4.
3) The "nub" end of the piston appears to be the same diameter at the piston rod bore and should fit through the piston rod housing seal.

Question 1) Is there a way to check if there is damage to the piston and/or seals in the cages (ie - could the failure be from a bound-up piston that the motor just "yanked" so hard that it sheared off in tension?) I cleaned the piston and cages off with a rag, applied new food grade silicone grease to the seals and piston and reassembled. It seems to move freely with a slight "ratchet/notch" feel as the piston faces move from one seal to the next.

If I were a plumber, I'm sure I would just say "your piston is broken and you need a new assembly" with a nice margin on parts and labor.

But since I'm doing this for a friend and my time is exchanged for beer.

Question 2) Am I wasting my time just replacing the piston rod (assuming the 5000 is the same as the 5800) or should I just tell friend he needs to pony up for the $80 and be done with it?

Not my money and I get the same amount of beer either way! ;-)

 

[Reach4]

I don't know the answer to that, but I would tend to think the piston and seal spacer kit would be wise. You are talking 5800 and not 5810, just to make sure.

I do suggest you get a tube of Dow MOLYKOTE 7 Release Compound on order. That is one step lower viscosity than Molykote 111. Use that to lube piston and seals when you put seals back together. A little goes a long way. That may be the food grade silicone that you are referring to.

 

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[ditttohead]

I am fairly certain the 5000 rod will work on older 5800 valves. That part was redesigned a couple years ago to strengthen that part so it is likely you have the older 5000 piston rod.

 

[ditttohead]

edited to clarify, I meant to say "older 5800 valves". The older 5800 use the same rod. The piston was recently redesigned so the old piston will not work on newer 5800 valves. I have a bulletin on it somewhere at the office but since I am travelling as usual...

Thanks for the heads up.