Fleck 9100SXT - Flow Indicator Intermittently Blinking

[ditttohead]

Simple solution.. this is a very common problem.

As the water heats it expands, the "extra" water has to go somewhere, so back into the city supply it goes. A thermal expansion tank wont do anything to prevent this water movement. A thermal expansion tank is used to absorb the extra water when the house has a check valve or backflow preventer. Install a spring loaded check valve on the outlet of the softener, this will usually correct the problem.

The meter is on the outlet of the softener and since it is a hall effect turbine, water flow direction does not matter, it will read in either direction.

 

[Torque]

Simple solution.. this is a very common problem.

As the water heats it expands, the "extra" water has to go somewhere, so back into the city supply it goes. A thermal expansion tank wont do anything to prevent this water movement. A thermal expansion tank is used to absorb the extra water when the house has a check valve or backflow preventer. Install a spring loaded check valve on the outlet of the softener, this will usually correct the problem.

The meter is on the outlet of the softener and since it is a hall effect turbine, water flow direction does not matter, it will read in either direction.

This is my current plan, currently I am planning to use a dual spring loaded check valve on the outlet of the softener. I'm assuming this will keep any expansion from the hot water tank from pushing back and engaging the hall effect.

Regarding the comment about this being a very common problem, every company I've talked to has been at a loss, including various softener companies.

However, one comment you made has me slightly confused, in my current design what is my expansion tank doing if anything? Since I have no check valve currently, is the expansion tank effectively not doing anything?

 

[Sponsor]

 

[Reach4]

Since I have no check valve currently, is the expansion tank effectively not doing anything?

No, IMO. Oddly enough, I think it is contributing to your problem.

If you are electronics oriented, think of it as a capacitor. That forms part of the path of a metaphorical AC current coming in from the city pipe. Your turbine is acting as a recording AC milliammeter.

 

[Bannerman]

The expansion tank pressure will be currently the same pressure as the municipal water system, often 60 psi.

The expanding water within the water heater will need to go somewhere, but water will always take the path of least resistance. The expanding water will not, therefore, flow into the expansion tank as that will increase pressure higher than the municipal supply pressure, but there will be less resistance back through the softener to the water supply main.

The check valve after the softener will prevent backflow through the softener, so the only place the expanded water can be absorbed will be into the expansion tank.

 

[Torque]

Interesting insight, I didn't even consider the expansion tank to be equal to(or more) than the city main. This in theory would support the idea that it is flowing in the wrong direction.

Sounds like the dual check valve is the way to go. Not sure I'll get to it this weekend, but I'll update once I complete it.

 

[Reach4]

Interesting insight, I didn't even consider the expansion tank to be equal to(or more) than the city main. This in theory would support the idea that it is flowing in the wrong direction.

Sounds like the dual check valve is the way to go. Not sure I'll get to it this weekend, but I'll update once I complete it.

Nobody is suggesting to you that you should put in two check valves.

 

[ditttohead]

Double checks were a code cheater that is no longer allowed in place of a backflow preventer. A standard single check should be just fine.

And the other companies you talked to probably lack the field experience that only a few people in this industry have. I personally have worked the field for 30 years with the majority of that being in the commercial and industrial market. The installation of a check valve without a thermal expansion tank is a sure fire way to test the P&T valve. As stated, the thermal expansion tank will have no affect since the very slight increase in water pressure is shared across the entire plumbing system. When you install a check valve you have isolated your water heater plumbing from the community plumbing system.

The flow of water back and forth across the meter usually only makes a tiny amount of water. It rarely affects the systems efficiency. You may only notice a gallon of water change in the meter over the time of an hour.

 

[Reach4]

The flow of water back and forth across the meter usually only makes a tiny amount of water. It rarely affects the systems efficiency.

Torque has a very unusual situation. His usage indicator flashes even though he has not been using hot water. The indicator stops flashing if he closes the valve in series with the water meter. While that could happen as the water in the WH heats after hot use, his appears to be more persistent than could be explained with the normal stuff.

I think he gets an alternating pressure component on top of his steady state pressure.

We all agree that a single spring loaded check valve on the output of his softener, and keeping the thermal expansion tank, will solve this whatever the cause.

 

[Bannerman]

There only needs to be at least one of the two magnets mounted on the turbine to pass the sensor in either direction to cause a pulse which is detected as water flow. If say 80 pulses = 1 gallon, each time a magnet passes the sensor will be counted as 1/80 of one gallon.

If one of the magnets is located closeby to the sensor, then as water expands when heated, even a tiny volume pushing back through the turbine could cause that nearby magnet to pass the sensor. As water will contract again when cooling, that same water may flow forward again through the turbine, causing that same magnet to again pass the sensor and be counted once more as additional flow. If this should happen repeatedly, or if there is more expansion occurring to cause 2, 3, 4 ... magnets to pass, that will add up over time even as only a small volume has only really moved back and forth through the turbine.

 

[ditttohead]

Exactly but.. the 3/4" turbine meter has a K factor of 133, so for each gallon of water the meter has to recive 133 pulses.

Like I said, this is a very common issue, but if you watch the readings, the water usage may barely show any actual usage even though the meter is seeing water flow. This is an extremely sensitive meter.

https://view.publitas.com/impact-water-products/2018-catalog-final/page/128-129

 

[Torque]

Thanks for the input everyone.

My understanding was the dual check valve was superior to a single check valve in this instance - https://en.wikipedia.org/wiki/Double_check_valve

More specifically, the dual check provides a more reliable seal and avoids even minor leakages(or backflow in my case).

Is there any reason to just use a single?

@dittohead - Your experience is showing. You are correct in your assumption that I am showing 1-2 gallons of usage per hour.

 

[ditttohead]

Sounds about what I would expect. A single check is simply more common, and should eliminate this problem if you care to fix it. I am partial to Apollo check valves myself, a little more expensive but very high quality. https://www.zoro.com/apollo-ball-co...bronze-1in-6110501/i/G0936835/#specifications

 

[Reach4]

My understanding was the dual check valve was superior to a single check valve in this instance - https://en.wikipedia.org/wiki/Double_check_valve

More specifically, the dual check provides a more reliable seal and avoids even minor leakages(or backflow in my case).

I had mis-read your reference to a dual check valve, and thought you were proposing to put check valves on both the input and output of the softener. My mistake.

 

[Torque]

Not a problem! I apologize for not being more clear.

To be clear, I will be placing the dual check valve only on the outlet side of the softener, prior to expansion tank.

Appreciate the help from everyone, I will keep you all posted.

 

[Torque]

So my plan is to install the dual check valve post softener before the water line tee's off to the expansion tank and the rest of the house. It is pictured in green. Please let me know if you all are in alignment.

 

[Reach4]

It is pictured in green. Please let me know if you all are in alignment.

We are, but your green rectangle needs the arrow. Or maybe two arrows in series in your case.

 

[Bannerman]

the dual check valve was superior to a single check valve in this instance -

Your linked wiki article states "A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination."

A double check backflow prevention device is often required where clean potable supply is directly feeding a non-potable system such as an irrigation or fire suppression system. Any backflow could introduce contamination to the potable supply so using a double check will provide redundancy if one check valve should remain stuck open by debris.

In your situation, there is no risk of contamination if the check gate should remain stuck open. In consideration of the filtration in place before the softener, there is also little likelihood there will be debris which may prevent the check gate from closing fully.

In addition to Dittohead's previous statement regarding a single check valve being more common, a single also should be less expensive and there will be less pressure loss through the device.

 

[Reach4]

In your situation, there is no risk of contamination if the check gate should remain stuck open. In consideration of the filtration in place before the softener, there is also little likelihood there will be debris which may prevent the check gate from closing fully.

That double check valve will do the job fine. A little extra pressure drop is inconsequential in this job. This is not to say that your points are not correct, but little overkill will not hurt. I sometimes like overkill. It's not like he proposed a saltless softener for softening or a copper bracelet for disease treatment.

 

[ditttohead]

I have a copper body suit, I plan on living forever!

 

[Torque]

Good news everyone! I put on my magnetic balance bracelet and was able to resolve the issue. Putting in the dual check valve has solved the issue.