Thetford Tecma toilet always shows red

[ken.knutson100]

“Update it’s working now (back to green) and sure why?!” 
Not sure if this is the correct place to post this question but we have a 2009 Dynasty 45’...Bath and half ...Thetford Tecma macerating toilets...tanks have been dumped and cleaned twice...the rear toilet shows green on the push pad like it should when it’s empty but the front toilet is always showing red. You can bypass it by holding the flush button down for 8 seconds but then it locks it out for a period of time because it thinks it’s full. I’ve tried disconnecting the sensors but it still shows red. This switch is new as of last November. I’ve tried contacting Thetford but was on hold for 25 minutes before I just hung up. 
Any suggestions??

Edited July 15, 2020 by ken.knutson100
Updated it

[Hypoxia]

Page 17 https://www.thetford.com/wp-content/uploads/2015/01/38996A-TecmaSilenceRV-Eng.pdf

[ken.knutson100]

2 hours ago, Hypoxia said:

Page 17 https://www.thetford.com/wp-content/uploads/2015/01/38996A-TecmaSilenceRV-Eng.pdf

Thank you and I did read that already. The sensor has been working since 2009 so I assume it’s installed correctly and there is enough ventilation. I’ve disconnected the sensors and power and still is red. I called Thetford and was on hold for 25 minutes and didn’t get a hold of anyone 

I’m just wondering if there is a work around to make it work again other than having to hold the flush button down for up to 10 seconds 

Edited July 15, 2020 by ken.knutson100

[ken.knutson100]

Update...so this morning after two days of it being red it’s now green again and working correctly. Not sure why? I’ll keep you updated if it changes again ...when it not working normally 

[amphi_sc]

Mine did that.  Tried all type tank cleaning...happy camper extreme et al.  Finally tried a tornado turbo nozzle, cut off the tank mount flange so I could screw it onto a garden hose and shove it up the black tank thru the valve.  It beat around and a lot of scale came out.  I'm assuming some scale had partially come loose next to the input and that it would trap water there throwing off the stick on sensors that are right there by the input.  A lot of the scale came out as grit, a few quarter size flakes, and a couple of flat pieces maybe a couple inches in diameter.

Mine would be green for a flush or two, then turn red.  Interesting observation was that I could back fill the tank from the sani-flush and it would cycle properly turning yellow at 70% and then red about 100% on the Alladin.  But one or two flushes on an empty tank would always turn red.  Thus my theory of loose scale by the input....

 

Since letting the tornado beat the inside of the tank, it has been functioning normally.

 

FWIW, Al

Tecma Silence mascerator

[jehlenbe@bellsouth.net]

I have had the same problem with my Tecma toilet.  Try using Thetford's Blaster and drive with the tank half full.  It cleans out the tank for a while.  When I am traveling  I equalize the gray water in the black tank and dump when I arrive  at my destination.  Not great but seems to  work

JACK & BETTY

11 DIP / 14 CRV

[stenderken]

I also have a 2009 Dynasty and was able to correct the red light problem by removing the sensor pad on the outside of the black tank.  I cleaned off the sticky stuff that held the sensor in place and re-installed the sensor with clear 3M double sided tape.  Has worked fine for over a year now.