Tunze 3152 sensor problem

[lndshrk]

Hi. I have a 3152 and I have noticed that lately the ATO is not switching on when the water level drops. I checked to see if it was simply the float being stuck such that it was not dropping with the water level, but it is not. I tried lifting the entire unit out of the water and wiggling it to make sure it is free, but it just does not come on. ONLY after disconnecting the power from the controller all together will it apparently reset and start pumping again.

This happens at least once a week. The unit is maybe 6 months old.

Any ideas? Do I need to replace?

Thanks

 

[rvitko]

Read pages 22-28 of the manual, it has a timer safety in case the float were to ever fail. By default this is 1.8 minutes, if the pump is ever run continuously for longer than this time it pulses the pump for a time as an alarm and then shuts off until you cycle the power. On tanks larger than 25 gallons you need to extend this to 3 minutes, the manual pages cover how to do this. Past 52 gallons the Nano Osmolator is not suitable though it may work on up to about 65 gallons if the evaporation rate is lower. I suspect with warm weather starting, the evaporation has increased and that is why this has just started now.

 

[lndshrk]

Thanks for that. Seems like a reasonable explanation. The thing is, it is on a 29g tank and where the sensor is positioned if it did run a full 1.8 minutes, the tank would overflow. If it is theoretically topping the tank of regularly, i don't see how the level could get so low as to ever result in the pump running for a full 1.8 minutes and result in a lock out situation. In fact, even after a reset, it usually tops it off with in about 15-20 seconds or so.

But, based on your suggestion, I think I have another theory that maybe could explain it. I use kalk in my topoff bucket. I know sometimes the kalk clogs things up down there a bit and maybe the pump is switching on but not actually pumping water. This would explain how it could run for the 1.8 minutes before locking out.

 

[rvitko]

I would try the 3 minute extension, I am almost sure this will solve it.