Osmolator overfilling

[jurgenph]

Tunze osmolator is overfilling all of a sudden.

This happened three days in a row now.

It will fill past the optical sensor, then trip the second float switch, and set off the high level alert.

I unplugged it when that happens. Let water evaporate, until the level is below both sensors, then I plug the osmolator back in.
It will start filling, and STOP, when it reaches the optical sensor. But then a few hours later, it will fill again, and not stop until it trips the float switch.

It had been running without problems for many months. Until three days ago, then it started to behave like this.

I cleaned the sensor, it is spotless now, but that did not solve the problem.

Anything else I can do?


J.

 

[rvitko]

Usually overfills are caused by bubbles or siphons, this is a general trouble shooting list, it does not sound like a siphon-


1) A siphon, if it is a siphon the issue will be seemingly random, it will tend to only occur when the reservoir is full and the water will fill to a level possibly above or just below the float. Siphon situation 3 is the most probable cause but note as shown in 4 that a loop will not solve it, the end of the hose must always terminate above the reservoir water level.

Siphon-Situations-688x459.png

2) A sensor issue. The first test is to use the self diagnostic test on the Osmolator to verify the sensor is in working order.

1) With the sensor completely wiped dry, plug in the controller. The sensor MUST be clean and dry for this test to work, a wet or dirty sensor will always fail.
2) All 4 lights will flash and it will beep, a single light will show for 1 seconds and then the normal 15-20 second pump run at startup will begin.
3) This light that is on one second is the optic sensor status, green means pass, yellow means it is marginal, red means it failed.

Assuming it passes the self test the issue is bubbles, optic sensors work by detecting the refraction of air vs water and make no differentiation between a bubble or being dry. The most overlooked source of bubbles is placing the top off hose in the vicinity of the sensors, the incoming splash will introduce bubbles and cause a fill. The hose can be routed to any area of the sump or main tank, and the optic sensor must be in a calm and bubble free area. A definitive test to verify bubbles are the cause is if you can catch it in the act of an overfill and wipe your finger across the sensor and filling stops within 5 seconds, the cause was bubbles.

3) There is a 3rd possibility but this is relatively obscure and only will apply to tanks under 50 gallons or due to a misunderstanding of how the Osmolator works. The Osmolator has timed functions in addition to sensor controlled functions and for the first 25-30 seconds it is not actually detecting water levels and is instead running a series of self diagnostic tests. The pump will always run for 15-20 seconds when you first power it up, this is so the installer can verify the pump is operational and the pump and tubing are primed and ready to fill. Also, the Osmolator always waits 5 seconds to fill to account for waves and surface movement and overfills for 5 seconds so the pump is cycled on less often. If the tank is under 50 gallons you need to open the controller and reduce the pump speed to "œnano" and if it is under 30, an additional restriction such as a drip irrigation valve might be needed, this will reduce the amount of water added by these timed sequences to avoid raising the float.

 

[jurgenph]

thanks Roger!

i wil try the diagnostic test later today.

FWIW: it's not a siphon, the fill tube is above the water level, in an area where the level won't go up, ever, unless i overflow the tank.

bubbles: i'm also 90% sure that there are no bubbles stuck to the sensor. i've dona a visual inspection every time it overfilled the last three days.

my tank IS smaller than 50 gallons, and the section that holds the sensor is "pretty small". but up until now, this has never been a problem. i do not recall if i set the controller to nano when i installed it. do you happen to have a quick link to some instructions on how i can check/set that? i don't think that i remember where i put my manual


J.

 

[rvitko]

You can download the manual on Tunze.com, the pump speed is easy to set. Undo the two screws on the back of the controller, roughly center right on the board is a red potentiometer labeled nano to maximum, from the factory it is set in the middle.

 

[jurgenph]

diagnostic test:green light.

opened up the controller box, and dialed down the pump flow

turned it on, it started filling, and stopped when it reached the sensor.
so far, so good.

a little later, i hear the pump turn on again, and with the water touching the sensor, it just kept filling. i pulled the sensor out, wiped it clean/dry, held it touching the water, dunked it under water, but nothing stopped the pump.
i had to unplug it to stop the filling.

something isn't right

Roger, what's next?

 

[rvitko]

Try this double test-

Out of water you got green so it passed, but we want to see that in water you get red and it fails.

How old is it?

 

[jurgenph]

Try this double test-

Out of water you got green so it passed, but we want to see that in water you get red and it fails.

How old is it?

will do that test later today.

i purchased it November 18, 2017


J.

 

[rvitko]

Let me know, I suspect it will give green when wet and then a new optic sensor will solve it and from that time period it will have the newer plug and you can change it yourself.

 

[jurgenph]

Green light when dry
Red light under water

Plugged everything back in
Pump comes on, fills up until the water reaches the sensor, stops.
Some time later, it kicks on again, and keeps filling until it trips the float switch.

I have not been able to see what light is on when it starts the fill that trips it. By the time I get to it, the high water alert is already going off.

I don't know what to say... But something is broken


J.

 

[rvitko]

I assume you ruled out bubbles and that the top off hose is not near the optic sensor as it is a source of bubbles from the incoming water. If those check out (you tried the bubble test I described of wiping your finger under the sensor when in the act of overfilling). I think the best step is we send a new optic sensor, PM me your address.

 

[jurgenph]

yeah, fill hose is unable to reach the water level, the tank would pretty much overflow if that happened

one of my tests was to take the sensor out, wipe it clean, then put it back in the water, none of those actions made it stop filling.

J.

 

[rvitko]

What I mean is the top off hose should be routed several inches from where the sensor is. The splash of incoming water adds bubbles.

The valid test for bubbles is leave the sensor exactly where it is and just swipe your finger across it. The sensor only detects air vs water, a few clinging bubbles can be interpreted as dry.

 

[rvitko]

It should stop within 5 seconds of wiping your finger under the sensor if it is bubbles.

 

[jurgenph]

What I mean is the top off hose should be routed several inches from where the sensor is. The splash of incoming water adds bubbles.

The valid test for bubbles is leave the sensor exactly where it is and just swipe your finger across it. The sensor only detects air vs water, a few clinging bubbles can be interpreted as dry.

It should stop within 5 seconds of wiping your finger under the sensor if it is bubbles.

the fill hose is in a different sump section, where the overflow enters, and the skimmer sits there as well.

the sensor is in the final sump section, where the return pump is.

i'll try the wipe test, and let you know what happens.


J.

 

[jurgenph]

It should stop within 5 seconds of wiping your finger under the sensor if it is bubbles.

No amount of wiping made it stop.


J.

 

[rvitko]

I had forgotten about Labor day but we are set up to mail out the sensor today.

 

[jurgenph]

thanks Roger!

i did some more tests over the weekend, but nothing worked.

plugging the controller back in with low water level, or high water level.
both resulted in an overfill.

one more question... when the pump is on, is the high or low level list aslso supposed to be on? so it shows why the pump is on?

every time that it was overfilling, the only light that was on was "pump on" nothing else.


J.

 

[rvitko]

Just pump on, too high means the float is raised, too low means it ran 10 minutes and timed out.

 

[jurgenph]

Roger, i received the new sensor, installed it last night, and so far, all has been well, it's working as expected! thanks a lot!

didn't think that a sensor that doesn't look like it has any moving parts in it would fail.

i did have a quick scare when i opened the mailbox though.
USPS decided to walk a herd of elephants over the package.
the sensor seems to be USPS elephant test proof

J.

 

[rvitko]

I am sorry it arrived like that but at least the part survived. Thank you!