Thetford Tecma Problems

[SloPoke]

We have a 37ft Allure 470 and the Thetford Tecma toilet thinks that the black tank is full at all times. Not sure if the full tank sensor has fallen off the black tank or the control board is going bad. Has anyone had this problem with their Tecma and what was the fix?
Thanks

[Old-Biscuit]

IS tank FULL?

There are only 2 sensors on tank....
1 for HIGH (RED) and 1 for MID (YELLOW)
Both are sticky taped to outside of tank and are replaceable (Sensor with 3' lead)

Odds are bad sensor vs control box unless other functions are not working

You can manually override HIGH level by holding any flush button for 6 seconds

System layout pg. 5&6
http://thetford.com/wp-content/uploa...lence-Plus.pdf

[smlranger]

Before you replace the red sensor, try pouring a gallon of white vinegar in the empty tank and drive the coach. When we've had a similar issue with the yellow light on an empty tank, someone suggested the vinegar and it was the only thing that worked. Apparently any goo that might stick on the tank wall near the sensor will cause that.

[SloPoke]

Thank You for the replies. The only other symptom is that it does not fill up to the correct height in the bowl after we flush it. I will try the vinegar first before I start pulling coach apart trying to find the sensors on the black tank. Did you only add 1 gallon of vinegar to an empty tank, or did you add water also?
Thank You

[BrianGlenn]

Thetford recommended water height is 1/2 inch above water outfall (exit hole..).

I adjusted mine following recommended programming procedure on page 1 of the above attached manual link:
Press both buttons simultaneously and hold. LED’s will flash indicating you’re in program mode. As water enters bowl, release fingers from buttons to set the level of standing water in the bowl. The level you set remains constant after each flush until you change. The minimum recommended level is 1/2” above the bowl out- fall.

As well someone also posted recently the height of the outlet anti-siphon hose (in back of toilet) was too low and it siphoned out water over time.

Hope this helps,
Brian

[Old-Biscuit]

Originally Posted by BrianGlenn

Thetford recommended water height is 1/2 inch above water outfall (exit hole..).

I adjusted mine following recommended programming procedure on page 1 of the above attached manual link:
Press both buttons simultaneously and hold. LED’s will flash indicating you’re in program mode. As water enters bowl, release fingers from buttons to set the level of standing water in the bowl. The level you set remains constant after each flush until you change. The minimum recommended level is 1/2” above the bowl out- fall.

As well someone also posted recently the height of the outlet anti-siphon hose (in back of toilet) was too low and it siphoned out water over time.

Hope this helps,
Brian

After changing water source (city water to pump or vs ) you may have to reset water level again

[SloPoke]

Thanks for the reply Brian. I have tried to adjust the height of the water level just as the instructions have indicated, but the water flow stops before reaching the correct level. I have tried many times to adjust the water height, the water flow always stops before reaching the correct level.
Thanks

[smlranger]

SloPoke, I used only the gallon of white vinegar but we did also use the toilet as normal after a while. I have a similar problem with my Tecma. I can adjust the water level by pressing the two buttons but it always eventually drops to about 1/2" below the top of the bowl outlet. I know the fix is to adjust the height of the discharge hose at the back but just have never gotten around to doing that chore.

[MikeyG]

SloPke:
Had the same problem with our Tecma. After repeated tank cleaning and no improvement, I removed the wet bay cover and sure enough, the full sensor pad had fallen off the tank. I replaced it with a little silicone at the edges of the pad and some Gorilla Tapeto hold it while the silicone cured . No problems since then.
Good luck,
Mike

[flaggship1]

Originally Posted by Old-Biscuit

IS tank FULL?

There are only 2 sensors on tank....
1 for HIGH (RED) and 1 for MID (YELLOW)
Both are sticky taped to outside of tank and are replaceable (Sensor with 3' lead)

Odds are bad sensor vs control box unless other functions are not working

You can manually override HIGH level by holding any flush button for 6 seconds

System layout pg. 5&6
http://thetford.com/wp-content/uploa...lence-Plus.pdf

When the tank is empty - the light is green on ours... then yellow, then red.

[Old-Biscuit]

Originally Posted by flaggship1

When the tank is empty - the light is green on ours... then yellow, then red.

Three colors (Green----any level below mid tank, Yellow----level at/above mid level & Red......highest level )

But only 2 sensors used....Yellow and Red. If neither are triggered than Green light is ON

[SloPoke]

Thanks everyone for the replies. I have dumped the black tank and added 1 gallon of white vinegar to it. Yesterday was a travel day, as well as the next 6 days (from CA to San Antonio TX). Will keep you posted.

[SloPoke]

smlranger, the 1 gal of white vinegar trick worked. I guess it was some residue stuck to the side of the black tank that was causing the problem. Thank You.

Now, this anti-siphon hose, how do I get to it to push it back up so I can get the water level to where it should be? I would be forever grateful for this information.

SloPoke

[smlranger]

Originally Posted by SloPoke

smlranger, the 1 gal of white vinegar trick worked. I guess it was some residue stuck to the side of the black tank that was causing the problem. Thank You.

Now, this anti-siphon hose, how do I get to it to push it back up so I can get the water level to where it should be? I would be forever grateful for this information.

SloPoke

There is a wooden box behind my Tecma that is attached with two screws thru the top. Remove the screws and the box lifts out exposing the back of the toilet with all the connections. I looked at mine but was not able to move that discharge hose on the connection. I decided to leave it for now and address the issue at another time.