Fleck 5600sxt Rapid Rinse issue - loss of pressure in house

[t33]

I have a Fleck 5600sxt which is about 6 years old. About a year ago it starting having an issue with the Rapid Rinse portion of the regeneration, but other than that everything seems to be working fine. The regen time is at 2am, and the symptom is that the next morning all of the 2nd story bathrooms have air in the pipes. (Main floor has minor sputtering sometimes too, but not always, and softener is in the basement.) After some troubleshooting I determined that the pressure drop only happens during the rapid rinse cycle.

Here's my theory:
I think Rapid Rinse is similar to In Service except the drain valve is open. I think somehow during Rapid Rinse the input flow from the main is getting impeded. I have a Moen Flow auto-shutoff valve just after the main water meter, and I think when I first got it installed, during RR I thought I saw around 6-10 gpm of flow on the app. But now, during RR, the app shows about 0.5 gpm. I also have pressure gauges on either side of the softener and I can see it staying at around 60psi on the input side, but on the output side, as soon as RR begins the pressure falls down to about 10 psi quickly, and slowly goes to 0 over the next 5-10 minutes. As soon as RR is over the pressure on the output side of the softener goes right back up to 60 again. So, during RR, I think the drain valve is open which allows 5-10 gpm to flow out, but only 0.5 gpm is coming in, so the water in the rest of the house is "falling down" and out the drain due to gravity.

I'm guessing that I could replace the control valve and the problem would go away, but I'm wondering if there might be a more inexpensive fix. Does it make sense that the way the valve changes positions, that something could block the input flow during RR but not In-Service?

In the meantime, since there doesn't appear to be any other issue with the softener, could I completely skip the RR step? If there is some benefit to having the RR, could I skip it and then open the closest toilet flapper for a few minutes after regen is done?

 

[Reach4]

Rapid rinse is like backwash, except the direction of flow is different. They both use the drain line.

Air after regen would normally be one of these:
o air check valve is not closing
o there is a suction leak in the brine line or the path from the valve down to the air check
o well runs dry, and the pump sucks air.

If the water pressure drops to 10 psi after a while, you may be sucking air.

With a 10 inch tank, expect 2.4 gpm for backwash *and* fast rinse. With a 12 inch tank, expect 3.5 gpm.

You could run the drain line into a bucket and figure out the actual gpm. It is the DLFC that controls the flow for backwash and RR.

If the input pressure stays over 30 psi, the well is not running dry... but is that gauge working? Will it go to zero?

If the pressure drop during RR is large, that is very weird. The input and output should be bypassed together during the RR, so there should not be a lot of drop between in and out.

 

[Sponsor]

 

[Bannerman]

Rapid Rinse and Backwash are performed at an identical flow rate.

Both the RR & BW flow rates, are governed by the DLFC (drain line flow control) flow restrictor which is a rubber type washer installed within the drain housing just prior to the 5600 drain connection. The drain flow rate required, will be in direct proportion to the diameter of the resin tank.

A softener utilizing a 9" diameter tank, will typically contain 1 cubic foot (ft3) of resin and will utilize a 2.0 gpm DLFC. A 1.5 ft3 softener, will usually utilize a 10" tank and a 2.4 gpm DLFC, while a 2 ft2 softener will normally utilize a 12" diameter tank and a 3.5 gpm DLFC.

The Brine Draw cycle of regeneration, will typically utilize a 60-minutes setting, even as the brine will be usually transferred from the brine tank to the resin tank within the 1st 15-minutes. The remaining 45-minutes of the Draw cycle, causes Slow Rinse flow to continue through the resin tank, which pushes the brine through the resin bed, and will rinse away calcium, magnesium, chloride and excess sodium to drain.

Once the majority of brine has been drawn out from the brine tank, the 'air check' valve located at the bottom of the brine pickup tube within the brine tank, will close to prevent air from being drawn into the resin tank during the Slow Rinse cycle. If the air check valve cannot fully close due to debris or foreign matter becoming stuck in the valve, then air will be drawn through into the resin tank, which can then enter the plumbing system once the regeneration cycle has concluded.

You could initiate a manual regeneration during the day while you are present. This will allow you to monitor the regeneration cycle, to determine if you can hear air being drawn into the air check screen once the remaining brine level is low. If air is entering through the air check valve, the brine pickup assembly will need to be removed from the brine tank, to allow it to be flushed with pressurized water from a garden hose nozzle, both externally and internally.

Here's a photo showing the air check screen which contains the air check valve:

Image of 2.4 GPM DLFC restrictor:

 

[t33]

Thanks for the info. I'm on city water (no well) and my resin tank is a 10" (1.5cf and 48K max grain), so I suppose that means my DFLC washer should limit the drain to 2.4 gpm. So I think either I misremembered that the RR step once had a higher flow reading from my Moen valve, or the Moen valve was wrong, or maybe my washer is missing or defective.

I think I can rule out the aircheck getting stuck during brine draw. I fully cleaned out my brine tank, put more salt in, and then triggered a regen so I could fill the tank. I manually skipped BW and BD (to rule out the possibility of sucking air), and then at RR the identical problem happened. (Pressure holds before the softener and within seconds drops after the softener. My Moen showed 0.5 gpm again.) I stopped the RR step after a few seconds before the water could start falling out of the upstairs pipes. Then continued on to BF to refill the brine tank.

So I think my theory still holds, that during RR something is blocking the input and the drain is allowing more than that out. That's if I can trust the Moen valve flow rate.

I found that I can enter diagnostic mode in the control valve and it will show the current flow rate. I'm going to do another regen tonight and step through every step, and look at what the diagnostic flow rate reports, and also compare that with the Moen valve. I don't think this information will help solve the problem, but at least will help confirm if the Moen flow rate is accurate. (I think it's unlikely the Moen and Fleck would agree and both be wrong. )

In the meantime, regarding my other questions, can I skip RR generally, and maybe run a toilet a few times to get a similar effect? (Until I fix the problem for good.)

 

[GN_Mike]

I am wondering if you ever solved this problem? I just noticed that my Fleck 5600 SXT controller (3 years old) is doing the EXACT same thing. The BW and BD portions of the regen cycle run fine, but then during RR, there are two problems:

1. The RR flow rate through the drain is very low - a fraction of what is flowing during BW.
2. Water pressure in the house is basically zero during RR. During other portions of the regen cycle (BW, BD, BF), the house has fine water pressure.

Like you, I do not believe it is air entering the system through the air check screen. I manually cycled through the regen steps quickly to ensure that the BD wasn't even coming close to draining the brine tank, and the exact same problem resulted - low RR flow rate and no water pressure in the house for the entire time that the unit was in RR. As soo as the unit advanced to BF, water pressure in my house was restored.

The only thing I can add is that, the moment the unit switches from BD to RR (while ---- appears on the display), the flow rate through the drain line is high for just a second or two during the transition. However, by the time the transition is complete and the timer starts counting down, the flow through the drain is weak, and there is no water pressure in the house. As soon as the unit moves from RR to BF, water pressure is restored (and the brine tank is filled to the normal level).

Did anybody ever figure this out?

 

[t33]

I am wondering if you ever solved this problem? I just noticed that my Fleck 5600 SXT controller (3 years old) is doing the EXACT same thing.

I haven't solved the problem yet. Some updates related to my previous posts though: the flow during BW is in fact 2.4-2.5 gpm according to my Moen shutoff meter. This is what it should be according to the size of the washer I should have. During RR it's about 0.5gpm according to my Moen, and this is bad. (I must have been mistaken in my original post that RR was ever higher than 2.4...) I believe the math is correct though that with water going out the drain at 2.4 gpm and input at 0.5 gpm, it's draining water in the house as I suspected. I was unable to use the Fleck diagnostic mode to confirm the flow rate reported by the Moen during a regen; I believe because that feature is disabled during regen. But in service, I confirmed the Moen and Fleck did match flow rates when I turned on a sink or flushed a toilet, so I believe the Moen is accurate.

So for now, what I did was change the RR time to 0 minutes so that it basically skips it. I make sure I'm around (and awake) when it regens and at soon as it switches to BF, I run the closest toilet for a few minutes to simulate rapid rinse (not sure if this is the best course of action though). Some notes about this:
1. My control unit allows me to set RR to 0 minutes, but also has an OFF option. I don't know why, but if I choose OFF and hit next, it skips the BF time. I'm not sure what would happen if I selected OFF, but without a BF option I didn't bother trying it, so I'm using 0 minutes for now.
2. The RR position still happens even with 0 minutes set. It never starts the countdown, but it does show RR for 30-60s with the dashes while it cycles through. The drop still happens during this time, but usually doesn't get much lower than 5-10psi. This is almost enough to keep water in the upstairs pipes. Now I have minimal sputtering after a regen. When I go to flush the toilet for a few minutes I still get some brown water but it's far less than before.

Unless someone else has a better idea, my next step is probably to get the new replacement o-rings kit. I don't know what the innards look like yet but maybe one of them is ripped and is stuck in a slot restricting flow or something when it turns into RR position.

 

[Bannerman]

During regeneration, water flow will bypass the softener, so water will continue to be supplied to the home's fixtures, although that water will be hard. The only decrease in flow that should be occurring during regeneration, will be caused by the water that is being utilized for each phase of regeneration. Because the maximum flow will only occur during the Backwash and Rapid Rinse cycle, flowing to drain @ 2.4 GPM, the home fixtures should continue to be supplied reasonably high flows, especially if the home's main plumbing supply line is 3/4".

I suspect your 5600 will require a rebuild kit, utilizing new seals, spacers, brine valve seals, and possibly a new piston if the existing piston's Teflon coating is scratched, flaking or otherwise worn. If a seal and/or piston is damaged, the piston may not be moving freely as intended, so it is possible the piston is not being fully moved to the Rapid Rinse position during each RR cycle, which may be resulting in only partial flow to the valve's RR internal pathway, and also only partial bypass flow to the home's fixtures.

As your water is obtained from a municipal supply, suggest checking with your water supplier to determine if they are possibly utilizing chloramine (chlorine + Ammonia) as a sanitizing agent as opposed to plain chlorine. Many municipalities have been adopting chloramine as there are supposed benefits, but chloramine will degrade soft components such as seals, O-rings and softening resin more rapidly than plain chlorine. While 10% cross-linked resin will better tolerate constant chlorine exposure compared to standard 8% C-L resin, removing chlorine before a softener utilizing a backwashing carbon media filtration system will extend the lifespan of any resin and other soft components. When chloramine is present, it is almost imperative to remove chloramine to prevent needing to rebuild and re-bed the softener with new resin on a frequent basis. To effectively remove chloramine will be best achieved utilizing a backwashing filtration system equipped with 2ft3 or more of Catalytic Carbon.

The 5600 is a fairly simple valve to rebuild as a DIY project. Below, is a Pentair video showing the teardown procedure for the 5600 mechanical valve. Although the video is not showing an SXT controller, the valve rebuild procedure will be virtually identical.

 

[LLigetfa]

How many GPM can you draw from taps after the softener is back in service? Rapid rinse is a downflow operation that goes through the bottom basket so possibly the bottom basket is getting clogged/crushed. Possibly your resin is breaking down and the fines are getting caught in the bottom basket. As the basket clogs, there is significant pressure differential across it which can crush it, further choking off flow.

 

[Stevehandyman]

I have had the exact same problem for about 3 years now (Fleck 5600 Programmable). I finally fixed it; bought a rebuild kit but only used the seals(blue silicone) and spacers. The replacement plunger was a different color and looked slightly different so I didn't replace it. I already tried replacing the brine check valve twice because I thought that is where the air was coming from, but I think what was happening is; during the RR cycle, the pressure in the house was going low enough that a check valve in my toilet/bidet was allowing air into the plumbing. When I watched the RR cycle the pressure was indeed going down to 0. This still doesn't make sense since the flow should be going through the tank to outlet. But the center seal was extremely pitted and maybe was flattened out, so it was possibly preventing flow to the outlet??? Anyway, its working now. Don't allow this to continue if your system is doing this, because the pressure cycling is not good for your hot-water tank. My first tank only lasted 13 years before it cracked; I blame this on the softener causing pressure cycling in my plumbing. Now system runs BW=3.0 GPM, RR=2.45 GPM. Good luck!!