water softener makes astoundingly loud hammering sound

Old 07-03-07, 09:19 AM
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Question water softener makes astoundingly loud hammering sound

My water softener has been making an astoundingly loud hammering sound, it literally sounds like it's ripping the pipes out of the walls. The sound lasts for about 10-15 seconds. Of course this occurs in the middle of the night, so it gets everyone's attention right away.

I'm no expert on the details of water softener operation, I just get the basics, but here's what I know about mine.

I have an Autotrol Series 168 and a 460 NOVRAM MP. (Both of these seem to be part of the box sitting on top of my resin tank, so I'm not sure where one begins and the other ends, but I *think* the 168 is the mechanical part and the 460 is the computer part.) These were installed roughly 12 years ago, and have been maintained by occasional service visits.

We're only in the house on weekends. Typically this hammering sound, when it occurs, happens on the 2nd night we're there. I attribute this to the computer control of the NOVRAM noticing that there's been a jump in water usage (during the day between 1st night and 2nd night) and kicking in the regeneration cycle. If we stay longer, the noise may or may not repeat on subsequent nights (though I'm not sure whether this is because the regeneration cycle simply isn't happening -- the NOVRAM supposedly schedules regeneration based on water usage -- or if regeneration is happening without incident).

The local plumber has come twice already to address this complaint, so we've given up on him. No idea what he did 1st time. 2nd time he replaced (or rebuilt) the "valve", whatever that is.

The noise occurs near the end of the "regenerant draw - slow rinse" part of the cycle (at least that's where the arrow is pointing when it happens. After this horrible noise, there is a sound of a slow cycle of gurgling water, and that cycle gradually over 5 minutes speeds up until it sounds like a dam releases and there's a rush of water that goes out the drain. That lasts about 5-10 minutes. Apparently this is the "fast rinse - refill" cycle because that's where the arrow is pointing then, and then it stops, pointing at "conditioned water". Quiet again.

After this event, whenever we turn on any faucet, there's invariably air expelled at first. So obviously whatever happened is putting air into the pipes, which seems related to the hammering.

But why? Any ideas or suggestions will be most appreciated.

I might add that the water is not as soft as it used to be, nor is the salt in the brine tank being depleted at its former rate. On the other hand, the water is clear and tastes ok (and it certainly isn't clear coming out of the well), so the softener is doing some filtering.


Leland Woodbury
Old 07-10-07, 01:02 PM
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Smile Noise

The 168 valve uses an aircheck mechanism (floating ball) in the brine tank pick up tube that drops and "checks" to prevent air from getting drawn in after all the salt brine is drawn from the brine tank in the "brine rinse" part of the cycle. Either that ball is hung up or there is an air leak in one of the connections from the control valve to the brine tank.( causing the banging and air. Try starting at the control valve and follow the 3/8 tubing to the brine tank tightening connections along the way and if none are loose pull the pick up tube out and clean the end of if out with warm water and make sure the ball is moving freely. Reassemble and run 2 manual regenerations. Good Luck
TJ Hornet
Old 07-19-07, 03:46 AM
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I have the same problem with my new Fleck 7000. The problem is exactly what TJ described in his reply (air getting by the check valve after the brine has been sucked out of the tank) but a solution is not so clear. I have checked all my fittings and they are as tight as they can be. I manually tested the check valve by trying to suck air out of it and it is seems to be working fine. I've watched it go through a regen and when the check valve started thumping I wiggled it until until the check valve ball set and thumping stopped. Even with that there is air still getting by somehow, which fills up the tank and gets blasted out during the fast backwash. I emailed the experts at Water Value who sold me the unit and they said this is very common and there is really nothing you can do about it but live with it. Not the answer I was looking for. Everyone has great reviews of this unit yet it seems there is a inherent flaw in the design. I hope they're wrong and there is some way to solve this. After a regen and you open the tap you get a blast of air, which is can be very startling if you are not expecting it. That's certainly not normal and I hope someone can suggest a solution.
Old 07-19-07, 07:54 PM
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Fleck 7000 air issues

ttpiper, what kind of float are you using ?

Some of our dealers have noticed that the Clack version of the 2310 sbv will induce air at the grommet that seals to the float arm.

None of the 700's that I've seen have exhibited this problem at all.

If you want to confirm if the valve is innocent/guilty here, attach an inline shutoff on your brine line and run the system through a short brine/rinse with the shutoff closed, effectively eliminating the float from the equation.

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