Fleck 9100SXT - Flow Indicator Intermittently Blinking

[Torque]

I have a Fleck 9100SXT Metered Dual Tank Softener - 64,000 Grain per tank. The water flow indicator(water drop) is intermittently blinking and showing flow(roughly shows flow for about 5s every 2 minutes).

Entering the FR menu, the flow varies from 0.1 -0.3, again always lasting no more than a few seconds. This is where things start to get interesting, when I cross checked the water meter on my house, it did not show any flow. This leaves me with a couple of theories:

1. The "flow" is so low, that it's not actually pulling any water from the water main, thus the softener detects the flow, but the meter does not.
2. The softener is malfunctioning in some manner and detecting flow when there isn't any.

Theory 1 does not seem to be likely given the FR rate indicated, I would expect to see some change on the water meter for the house.

To test theory 2, I placed the softener in bypass and it stopped showing water flow. I then placed the softener back into normal operation, and turned off water to the various items that may call for it(water heater, ice maker, etc.). After ~2 hours, the usage had "used" 2 gallons of water.

I'm not sure where to go from here. But I am stumped.

 

[Reach4]

It could be that a check valve in line with the softener could help.
https://terrylove.com/forums/index.php?threads/water-softner-flowing-backwards.48959/#post-359726

 

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[Torque]

Thanks for the tip. This would actually make a lot of sense.

After installing the softener, the T&P valve blew on my water heater. I replaced that and added an expansion tank on the inlet side of my water heater.

I'm now thinking that the expansion tank may be causing some water to "slosh" back and forth and thus cause the continuous "flow".

Reading through that thread, would the proper course be to put a check valve on the outlet side of the softener before the expansion tank?

 

[Reach4]

The turbine is on the output side. However I think the check valve could be on either side. I see potential advantages both ways.

The check valve would be a spring-loaded valve such as you might use with a well.

 

[Torque]

I am semi concerned as to why I'd need a check valve though. I would assume that the expansion tank should be dealing with any backflow, or am I incorrect in this

 

[Reach4]

I am semi concerned as to why I'd need a check valve though. I would assume that the expansion tank should be dealing with any backflow, or am I incorrect in this

I see your point, and it is a good one.

OK. City water. So buying into this, the question would be why the the city water pressure would be changing every 5 minutes.

I suggest that you get a pressure gauge. A garden hose pressure gauge can go various places such as a hose spigot, a laundry supply, or the drain valve on your water heater. A 0-100 PSI would be better than the common 200. Some have a peak-indicating lazy/tattletale hand. https://www.acehardware.com/departments/plumbing/pumps-and-pump-parts/pressure-gauges/4509477

 

[Torque]

I actually have pressure gauges inline. I drafted this as an outline. All gauges look in normal range.

 

[Reach4]

Nice diagram of a nice system.

I am at a loss to explain things. Here is the closest scenario I can think of at the moment, other than a flaky turbine meter. For reasons unknown, there are small pressure fluctuations on your city water pressure. They are too small to observe on the gauges. These pulse through the to the pressure tank. Now that scenario presumes there is not an effective check valve at the meter, because otherwise the check valve would isolate the fluctuations when you are not using water.

If that is the case, you could remove the thermal expansion tank. You would see that the water pressure did not rise after a hot shower as you would expect with a working check valve on the incoming water.

So just to be clear, I am only pondering. I am not saying that I have any experience along these lines.

 

[Torque]

I've basically run out of ideas as well. I'm currently suspecting placing a check valve between the expansion tank and softener, however, that really doesn't explain why it's happening which is currently my bigger concern. And before I put that expansion tank in, I actually blew a T&P valve, so I'm thinking that's a must. I've called the seller and they're stumped, and I've called a water softener service company and they're stumped as well.

 

[Reach4]

Click Inbox above.

 

[Torque]

Replied. Still no solution though.

 

[Bannerman]

Is a check valve located where the water service enters the home? Is there any air trapped within the fire suppression system (sprinklers)?

Without a check valve to isolate the main line, water being heated will expand and will flow back into the municipal system or further compress air within the sprinkler system.

Although you installed an expansion tank on the water heater inlet, without locating a check valve between that expansion tank, the main feed and sprinkler system, any expansion that does occur will flow to the expansion tank, the sprinkler system and municipal service until pressure is equalized between them all. A check valve directly after the softener would confine the water heater thermal expansion to the expansion tank just installed and would not expose the softener to increased pressure occurring in the expansion tank.

 

[Torque]

The sprinklers are lawn sprinklers. Apologies for the confusion. Thus no air is trapped in there.

I do not know if there is a check valve where the water enters the home. My assumption would be no.

It sounds as though your recommendation is to place a check valve between the softener and the expansion tank if I understand correctly?

 

[Bannerman]

lawn sprinklers = irrigation sprinklers or system

I am suggesting a check valve after the softener.

Depending on hot water use and temperature setting, the cold may expand a considerable amount, thereby increasing the pressure substantially higher than the regular municipal pressure.

Although the softener will be tested and rated for higher pressure, by locating the check valve after the softener means the softener will not be subject to repeated higher expansion pressure which will quickly drop when a downstream faucet is opened.

 

[Torque]

lawn sprinklers = irrigation sprinklers or system

I am suggesting a check valve after the softener.

Depending on hot water use and temperature setting, the cold may expand a considerable amount, thereby increasing the pressure substantially higher than the regular municipal pressure.

Although the softener will be tested and rated for higher pressure, by locating the check valve after the softener means the softener will not be subject to repeated higher expansion pressure which will quickly drop when a downstream faucet is opened.

This is what my primary plan is, though my assumption is the expansion tank would have operated as a check valve. Is this not the case?

 

[Bannerman]

An expansion tank only provides space for the expansion to flow to. That expanded water would then flow out again to the fixtures when pressure is relieved so the process can occur repeatedly. If there was a check valve built into the expansion tank, then water would not flow out, thereby eliminating the effectiveness of the tank after it fills with expanded water the first time.

See figures 2 & 3 at the link below.
http://delcowater.org/thermal-expansion-tanks/

Without a separate backflow prevention device in-line before the water heater, cold water that had entered the water heater will expand when heated, which will flow in equal pressure to anywhere it can flow to. This will not only be to the expansion tank but also backwards to the municipal water main.

When a backflow prevention valve is installed prior to the water heater but if there is no exp tank for water to expand into, the water heater pressure relief valve will often release to eliminate the expanded water.

 

[Torque]

So did some more testing, and unfortunately now I'm even more confused.

1. Removed Magnet Sensor from Softener - Result: Flow Indicator stopped(as expected).
2. Turned off inlet to softener - Result: Flow indicator stopped.
3. Turned off every ball valve on inlet side(one by one going back towards the main). - Result: Flow indicator stopped every single time.
4. Turned off the outlet on the softener - Result: Flow indicator stopped.

My current thoughts is there a pressure differential on the main side. Therefore, I should place the dual check valve on the inlet side after the filters, but before the softener.

Any thoughts?

 

[Reach4]

For completeness, try the valve into the meter too. That maximizes any potential non-city influences. I predict that stops the flow indication also.

I wonder what could be pulsing the city water.

 

[Torque]

Did try that as well, and that also stopped the flow indication.

 

[Reach4]

You might chat with the city water department to see if you have a nearby pumping station. It won't help you probably, but it would be another interesting tidbit in an interesting case.