Problem with neutralizer backwash cycle causing water overflow and spillage

[Hollow Man]

I had a neutralizer and softening system professionally installed in my basement a year ago to counter the effects of my acidic well water. The system drains into my main drainage pipes, which go out to my septic tank.

Things appeared fine until about a month ago, when I noticed that during the end of the backwash cycle (last 5 minutes or so of the ~27 minutes total), water started to gush from the pipe hole that appears to be designed to deal with overflow, and did not stop until the cycle ended.

I had the installers come out last month and look at it. When they manually ran the cycle, the problem didn't happen. As near as I could tell, for a few weeks this continued to be the case, but just this last week, the last two times it's done the backwash cycle, the flooding and spillage occurred.

The timer that kicks off the backwash appears to be a Fleck 2510.

The guy who originally looked at it last month surmised there was some kind of blockage that had since cleared itself. He feels since the flooding happens at the end of the cycle, any blockage must be far along the pipe, or perhaps an issue with my septic tank. The tank was actually replaced under four years ago when we bought the house, and there's only two us living here, so I can't imagine the tank is completely gunked up. Everything's been fine for a year, so my assumption is the tank is big enough to handle the backwash cycle.

It's been quite cold here in New England lately...for all I know something is frozen outside and causing the septic tank to be prematurely filled, and that's why when the system runs at midnight, I'm seeing an issue, but when the guy tested it during the day, it was fine (but I'm really grasping at straws here, and have no evidence whatsoever to support such a hypothesis).

My concern is how to go about troubleshooting this issue. Right now the installers plan to come out on February 7 to look at it again, and suggested if the problem persists in the meantime, to unplug the unit until then.

I'm out of my league with this stuff. Any thoughts and advice would be greatly appreciated. Thanks so much,

-HM

[Gary Slusser]

The diagnosis sounds right to me but...

Twenty some minutes of backwash (and I'm assuming that is including the rinse time) is about right for a residential sized AN filter.

If you have a water softener it and the filter should be programmed to allow the softener to go into a regeneration until a couple hours after the filter does its thing.

You'd have to have someone look into the septic tank (literally) to see if the water/scum level is correct. Also, there could be something broken etc. on the outlet of the septic tank that is reducing the outlet flow and causing too much water in the tank.

I think 10-12 minutes of backwash and then like 10 minutes of pause before going into a 5 minute rinse might help. And to prevent a softener from regenerating for an hour or two after the end of the filter backwashing would cure the problem. Maybe the overflow is only when both do their thing on the same night.

[Hollow Man]

Thanks so much for the reply. I almost never catch the softener when it's going through its cycle. I believe the installer told me it happens after a certain amount of water is used, rather than every x days. I was also told that particular cycle pushes much less water. It seems to occur over a longer period of time as well.

The cycle that happens every 4 days kicks off at midnight. It runs for about 12 minutes, pauses for about 3 to 4 minutes, then runs for an additional 10 to 12 minutes. The flooding happens in the last ~5 minutes. Flooding has now occurred last night, and 4 days ago (Monday night). So I don't think it's happening when softener cycle runs as well.

The next time this is due to run is Tuesday night, but if I keep it unplugged for 24 hours, it'll instead run Wednesday night, when the temperature is supposed to be well above freezing, which may test my frozen outside theory. Of course if there's a problem with the septic tank hookup, I'll just get flooded again.

The question is, do I try that, or, turn off the timer for now and wait for the installer, who comes out a week from Thursday (almost 2 weeks away, ugh), and hope the problem occurs when they test? Or, do I try to call a septic company and see what they think?

Much thanks again,

-HM

[Mikey]

What happens if you flush a couple toilets when the backwash is backing up?

[Hollow Man]

What happens if you flush a couple toilets when the backwash is backing up?

I haven't attempted that. The installers told me not to run any water during the cycle. What are you thinking might happen?

-HM

[Mikey]

Turn off the supply valve at the toilet so you won't be drawing water through the system. All I'm interested in is -- will it flush normally, or will the "frozen" septic tank regurgitate the effluent? I'm betting on the former. Septic tanks generate some heat (some people claim you can warm your house with it, but I'm skeptical), and they're usually (by code) set below the frost line. In truly severe cold, with no snow cover, though, they can freeze (http://septic.umn.edu/factsheets/fre...lems/index.htm), so it might be worth a call to your septic tank installer to see what he thinks. You can get an idea of how deep your tank is by looking at the sewer pipe as it exits the basement -- the tank is lower (duh!) -- and you can compare that with the current frost line (your county extension office might be able to give you guidance in that area) to see how close you might be to having a freezing problem. The frost line moves pretty slowly, I'd guess, so a freezing problem wouldn't be likely to come and go.

[Hollow Man]

Interesting. I'm just afraid if I flush the toilet while the backwash is spilling out, the flooding will get ridiculously worse while the toilet is flushing.

Our septic tank definitely heats up. The snow will slowly melt where the tank is located.

I think it can't hurt to call the septic tank installers on Monday and see what they think.

Also, since the weather is supposed to be just above freezing on Monday, into the 40s on Tuesday, and possibly up to 50 on Wednesday, if the tank is frozen, do you think if I trick the system into running Wednesday night, that would be enough time to unfreeze, and see if I get flooding?

BTW, the last two times this week the flooding occurred (last night and Monday night), I believe the temperature was under 20 degrees. When the installer tested it for me last month, that day it was above freezing (in the 40s, according to past weather reports).

Thank you so much for all your time; it means a lot to me,

-HM (Gregg...handles can seem childish on forums like this )

[Mikey]

Well, circumstantial evidence does point to a temperature-related problem, but I'd bet a beer it isn't the septic tank. Map out the complete path from the backwash output to the drain line and on to the septic tank and see if anything might be exposed to the cold. and don't forget the vents. If, for example, there's a dip in the line that occurs in front of the cellar window the line rubs against. that would form a trap that could freeze.

Mikey (I've been called that for close to 70 years; sorry.) (In grasping at straws mode.)

[Hollow Man]

Who would be a good person to inspect that line? Plumber or septic tank professional? I personally don't have the expertise (but will surely have learned something by the time this is over).

[Mikey]

My gut feeling is that if it is a freezing problem, it's inside the house. Therefore I'd find a very good plumber; septic guys, in my experience, only work outside. You really need a problem solver, not a particular tradesman, but the right plumber could certainly do the job. Word of mouth, a top-notch GC in your area, Angie's List, etc., might find the guy or gal for you.

Do you know exactly where the backwash line ties into the DWV (Drain, Waste, Vent) system? Do you have a set of as-built plans? Is your DWV plumbing exposed from where the backwash ties in until the DWV pipe(s) exit the house, or is there some behind-the-wall exploring required? If the latter, be ready for an in-pipe camera inspection.

[Hollow Man]

Maybe I left out something in my explanation, because I'm not quite sure I understand why you think, if it's a freezing problem, it would be inside rather than outside. I can see exactly where the backwash line ties into the main drainage line in our basement, and it's a straight shot right out the back of the house (which is why I was thinking the problem is outside). All of it is exposed and easy to get to; nothing behind a wall.

[Mikey]

I can see exactly where the backwash line ties into the main drainage line in our basement, and it's a straight shot right out the back of the house (which is why I was thinking the problem is outside). All of it is exposed and easy to get to; nothing behind a wall.

That's what you left out; it simplifies things greatly, and blows my theory all to heck. I was thinking of pipes hidden behind walls in uninsulated basement space. But in general, outside pipes buried below the frost line don't freeze, especially when a couple hundred gallons of temperate water pass through them daily. I don't think it's a freezing problem any more, so I withdraw my beer bet.

Because (apparently) there are no problems disposing of normal household waste, there must be something unique about the backwash cycle that exposes the problem, whatever it is. I'd pursue Gary's line of reasoning (Post #2 above). The fact that the backwash dumps a lot of water in a short period of time might be the problem. The septic tank is just a holding tank -- the drainfield is where the effluent eventually has to go -- and the septic tank smooths the peak flows from the house to a constant but small flow into the drainfield. If there's insuficient headroom in the septic tank to contain the sudden surge from the backwash, things will back up. A typical household uses from 60 to 100 gpd per person, but it averages out over time, wheras the backwashes dump lots of water over a short period. Septic systems are usually sized based on the number of bedrooms in the home, number of people living there, the home’s square footage and whether or not water saving fixtures are used. Since the water treatment system wasn't installed at the time the septic system was installed, the septic system may be undersized.

How big is your neutralizer tank and softener system? A large (12" tank) system could be configured to dump 4gpm during backwash. If the softener and neutralizer dump at around the same time now and then, that would be a LOT of water going into what could be a weak septic system, overwhelming it.

It may be time to call the septic guy after all. There's an easy, but potentially messy, way to test the septic system, but I'd wait for the pro and see what he says. IMHO, it's unusual to replace only a septic tank, unless it's a very old, steel tank that's rotted away. Modern concrete tanks last forever, or close to it. There may have been a larger problem with the entire system, and the new tank was used in an attempt to cover up the real problem.

[Hollow Man]

According to the sales quote I was given, what I have is a EWS20FAN (2 cubic foot) Acid Neutralizer and EWS30KM (30K grain) Metered Softener. The Neutralizer has the Fleck 2510 controller and the Softener has a Fleck 5600 controller. Does this help you determine how big the tanks are?

When we bought the house, an inspection by the previous owner revealed that the septic tank was cracked, which is why a new one was installed, right before we bought the house (1000 gallon plastic Fralo). If I had to guess, due to this large dog fence that surrounds the back yard, they drove a truck in there to build it and cracked the tank (I know, a hypothesis, but it's the only thing I can think of that would crack the original tank).

Thanks again for all the information...it's very helpful,

-Gregg

[Mikey]

According to the sales quote I was given, what I have is a EWS20FAN (2 cubic foot) Acid Neutralizer and EWS30KM (30K grain) Metered Softener. The Neutralizer has the Fleck 2510 controller and the Softener has a Fleck 5600 controller. Does this help you determine how big the tanks are?

Not really, but one of the pros here could probably tell. The easiest way to determine how big the tanks are is to measure them. They go by diameter and height. Measure the diameter by measuring the circumference and divide by pi. Common sizes are like 10x54, 12x48, 12x52, etc. Again, Gary was headed in the right direction. If the 2510 and 5600 are demand-driven, it's likely that now and then they'll regenerate on the same night. If that happens, instead of a lot of water hitting the septic system in a short time, it'll be a LOT of water, and if the septic system is marginal, it will be overwhelmed and you'll see a backup. Tell us exactly how they're both programmed (your installer should have left the details) and one of the pros here can tell you what's up.

The "EWS" numbers look like internal codes used by the company -- maybe some outfit like "Eco Water Systems" or something. They package standard tanks and valves into their own proprietary systems, and usually don't tell you much about them.

[Hollow Man]

Just measured and did the diameter math: my softener (the smaller tank) is 10x48 and the neutralizer is 12x52.

Sadly, they never left me with details as to how the system was set up. All of what I've said comes from observation and what I remember they told me. The neutralizer does its thing every 4 days: about 12 minutes, stops for 4 minutes, goes again for another 12. The softener supposedly runs when we have used a certain amount of water (I cannot remember the number of gallons they said), and seems to take 2.5 hours. It happens very infrequently...I think in the year we've had the system I've only personally been up and noticed it doing its thing twice. They told me it will go through less water than the neutralizer cycle.

It's just peculiar that it took over a year before I started noticing a problem. Why now, if it's simply an issue of the system not being able to keep up? And why did it happen once in December, then I didn't notice it again until this last week? And since the last two times the neutralizer has gone (Monday and yesterday) it's overflowed, I don't think it's an issue with nights both the neutralizer and the softener go. The softener kicks off too infrequently to have caused an issue on both nights this week. It seems the neutralizer cycle is enough to cause it.

So many questions unanswered...I really do need a great troubleshooter,

-Gregg