I have a tank minder made by Sealand, now a Dometic division I think. The empty light stop working. The manufacturer's literature is worthless as it has no maintenance
nor troubleshooting info, so I went online and found a post that explained "fear not" to take it apart. I did so and now I've done it successfully so therefore thought I might give a more detailed post to others about how these things work and you can fix them.
The tank minder has a microswitch on each sensor (empty, 3/4 and full) and these are really quite hardy and dependable.
We humans dump calcium and others stuff in our urine and, therefore, the sensors are immersed in an envisironment that is not only pretty -----y but also is pre-disposed to allowing deposits.
The empty sensor is immersed the most (it's in the bottom of the tank) so it stops working first!
So, when your tank minder stops sending an "empty" signal, it's time for maintenance
Here we go:
- Free up your wiring so you can rotate the whole tank minder without binding wires. I had to untape my wiring as I have a great boat with a manufacturer that does everything tidy = Post Yachts.
- Do not cut wires--it's not necessary as this whole thing can be done in place, above your holding tank.
- Unscrew the 3" cap (you may need channel locks) that carries the sensors and lift the whole assembly out of the tank. It takes about four turns.
- Your empty sensor (the longest one) will look like it can never recover -- brown calcium-like deposits on it. Ugly, ugly, ugly. Fear not.
- Put on your rubber gloves, get a small flat head screw driver, a bucket to contain the scrapings, some Simple Green, and start scraping and cleaning. Patiently spray and scrape. It takes a while so put a dish over the holding tank hole to reduce odors. About a 20 minute job for mine and it was gross when I started.
- Test it with a cup of water holding in each sensor. (This likely will take two of you as the sensor lights are typically remote.)
- Get some good counter rotation on the wires by twisting it counter-clockwise and screw the 3" fitting back into the holding tank.
- Wash your hands, dump the bucket, clean your screwdriver.
- Grab yourself a BudLite as you're a hero.