Air visible in brine tube during brine draw

[nimjor]

I’ve been fighting with a Fleck 5600SXT that’s introducing air to my plumbing each time it regenerates. This obviously makes horrible noise in the morning when people first open most faucets or flush toilets. I’ve replaced the air check valve and float assembly (twice actually, most recently preinstalled with a whole brine tank replacement) and the clear brine tubing. I saw someone else on here had an air draw issue that ended up being caused by a hairline crack on the injector assembly. I’ve looked closely at mine but didn’t see any cracks, and I’m assuming that because I see air traveling up the brine tube to the injector assembly (during brine draw) that the leak must be upstream (one of the connections inside the brine tank). Is my assumption correct? If the air check is working properly and there are no leaks, shouldn’t the brine tubing only ever have water in it and no air? Or am I misunderstanding something? I just can’t imagine which connection could possibly be bad down there, given the replacements I’ve done and things I’ve carefully checked.

 

[zver11]

Is enough water getting into the brine tank during fill phase of regen? Check for clog in line/valve and BF setting (Brine Fill Time)

 

[Sponsor]

 

[Reach4]

and I’m assuming that because I see air traveling up the brine tube to the injector assembly (during brine draw) that the leak must be upstream (one of the connections inside the brine tank). Is my assumption correct? If the air check is working properly and there are no leaks, shouldn’t the brine tubing only ever have water in it and no air? Or am I misunderstanding something? I just can’t imagine which connection could possibly be bad down there, given the replacements I’ve done and things I’ve carefully checked.

I agree with your assessment. In addition, if the air appears before the brine is sucked down, I think there is a problem that is something other than the air check.

Now once the brine is sucked down, and the air check closes, the vacuum is higher. So if there is a small leak, the lower vacuum might not be big enough to draw in air. But if air comes in before the brine is down, we can say there is a problem other than the air check.

I wonder if it would be worthwhile to get a little vacuum pump. MityVac is a well-established brand. https://www.harborfreight.com/mityvac-vacuum-pump-39522.html

Another test that comes to mind is if you apply some air pressure to the hose, air should bubble out thru the brine. If you lift the the safety float, the air flow should stop. I might apply that pressure by mouth, and could feel the pressure loss, even if the pressure is low enough to not bubble.

Regarding replacing, the part that you have not replaced is the tubing. https://www.homedepot.com/p/Everbil...-D-x-25-ft-Polyethylene-Tube-301762/207144264