Tecma Toilet issue - 2007 Signature

[grizzly]

Have my Tecma toilet with 2 buttons and the red light comes on when full. Tank was emptied and flushed but red light still on and I can't flush it. Any solutions or work arounds?

[Dr4Film]

Bad sensor somewhere. Most likely on the tank. Possibly jumper the sensor once you find the faulty one.

Edited Wednesday at 10:08 PM by Dr4Film

[Rikadoo]

OMG🤦‍♂️ im always telling people electronics will fail at the most inopertune time but takes it to a new level🙀💩😳 dont mean to be laughing at a issue like that , but i had no idea you could be locked out from a toilet, so like is there an overide with that system???

[Dr4Film]

Obviously, the Tecma Toilet was engineered by someone who doesn't own an RV and probably has never even been inside of one.

[Frank McElroy]

35 minutes ago, Rikadoo said:

OMG🤦‍♂️ im always telling people electronics will fail at the most inopertune time but takes it to a new level🙀💩😳 dont mean to be laughing at a issue like that , but i had no idea you could be locked out from a toilet, so like is there an overide with that system???

Look at the side of your black tank and remove the wire on the high sensor.  But, be absolutely sure the black tank isn't full.  If it is full you could pump black water out your roof vent...

[grizzly]

16 minutes ago, Frank McElroy said:

Look at the side of your black tank and remove the wire on the high sensor.  But, be absolutely sure the black tank isn't full.  If it is full you could pump black water out your roof vent...

There are 2 sensors on top black tank and each has 2 wires, one brown and one black. Have disconnected all of them and red light still on

[Frank McElroy]

I was afraid that might happen.  The electronics have a fail safe that if a sensor isn't reading if defaults to a full tank.  Is it easy to peel the sensor off the tank wall?  

Have you already tried flushing the tank?

[grizzly]

Do those sensors just mount to the outside of the tank or do they go into it internally?

1 minute ago, Frank McElroy said:

I was afraid that might happen.  The electronics have a fail safe that if a sensor isn't reading if defaults to a full tank.  Is it easy to peel the sensor off the tank wall?  

Have you already tried flushing the tank?

Yes I have several times. I saw how to by pass it to get it to flush. I guess the next thing is to take the señor off then tank

[Frank McElroy]

OK, have you tried this - press and hold the flush more than ten seconds.  This should bypass and override the red light.

To bypass the sensor insert a 620 ohm resistor instead of the sensor.

[Frank McElroy]

1 hour ago, grizzly said:

Do those sensors just mount to the outside of the tank or do they go into it internally?

Yes I have several times. I saw how to by pass it to get it to flush. I guess the next thing is to take the señor off then tank

Yes, they just paste to the side of the tank 

[MyronTruex]

Quote

I have to press both buttons at the same time for about ten seconds to get the emergency flush. On my 2008 Endeavor the tank flush was at the opposite end of the tank providing little cleaning of the sensor end of the tank. I installed a second flusher above the sensor area and that really helped but since we fulltime I was always concerned about build up. Using a deck hole access device (???), I have a clear cover and can see if the tank is full. And when needed, the cover unscrews and my pressure washer can easily clean the tank spotless. 

At one point I moved my full tank sensor up a bit because it was reporting full when at the half way mark which was annoying. 

 

[grizzly]

Well the lights went back to green over night without doing anything. Strange but happy. I did do the by pass flush to use it. 1 went green about 8 hours before the other one did. Must be toilet gremlins in there. LOL Thanks to everyone especially Frank.

I found this and it might be helpfull to others:

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

[MPfeif]

I have had this issue, and the solution has been to 1) wait overnight like you did and/or 2) flush the black tank using tank blaster 3) driving with the black tank half full 4) always run water in the the black tank flush while emptying and/or 5) use a good enzymatic black tank treatment.

Because of the where the sensors are located at the very end of the tank, and both toilets (if you have two) dump into the tank at about the same spot, I suspect that a buildup there is causing the issue. While the capacitive sensors the tecma's use are less sensitive to crud building up than the resistive tank level sensors, they're not immune.

The toilets actually use separate sensors for 1/2 full and full, so if you look at the end of the tank (by the aquahot, behind the plastic panel, you'll see four black rectangular sensors stuck to the end of the tank.

[Dr4Film]

I wonder if the tank sensors that are used for the SeeLevel Tank Level Systems would work for those Tecma toilets. Those sensors are significantly more reliable than the ones used by Tecma.

[Tom Cherry]

Reading this topic out of curiosity and also to understand.

Frank has posted a solution.  If I understand the circuit as well as also having helped some folks over the years, this is a “unique” circuit.

See!evel is a capacitance system….

External tank monitors use a completely different method. SeeLevel is a dielectric (Capacitive) system that senses the difference between Air and Liquid

The Tecma sensor is a “POINT” contact or an inductive sensor.  If you read the literature, there are TWO and each has a specific value….and are marked HIGH and MEDIUM.  Frank provided the specific “bypass or work around” solution…..with the caveat that if the tank iS FULL….then there will be consequences.

Thus….SeeLevel will not work.

BUT….having been a process engineer and doing a lot of tank and level control projects….I read the SeeLevel manual.

The issue can be….Faulty HIGH sensor or too much “crap” where the sensor is mounted so that it THINKS, the level of the tank is high.

I’d suggest reading the SeeLevel manual on cleaning and then be prepared, as they state, to do periodic maintenance and try to keep the interior wall as clean as possible.  My take is that when the tank is not used…..the moisture that has wicked up the side walls will evaporate or dryout…..thus, the sensor gets a reading commensurate with a “clean” tank. Those of us with the pass through or contact probes know that after driving and getting on site, our black tank reading is useless….but in a day or so, it is a little more accurate.  Many folks stress and try to make that system accurate.  It will NEVER be such.

The SeeLevel has a calibration or adjustment….the Tecma is not designed to be “field calibrated”.

It MIGHT be possible, if the sensor is OK, to remove and reposition (horizontally) to another location on the tank sidewall that is not subject to build up….or not as bad….the SeeLevel info on the internal dynamics and how to keep their system functional is some of the best and most researched out there.  Way too many myths of how to have a pristine and spotless tank interior…..all you can can do is MINIMIZE the buildup….
 

 

[Dr4Film]

@Tom Cherry Can you explain the difference between "inductive" and "capacitive" to me as I have limited knowledge in that area of expertise, please?