Community Forums

cgarringer · 07-17-2017, 12:19 PM

Our black tank is empty but the sensor shows full. We know it is empty. Therefore, our Masterflush 8700 toilet is also showing a red light indicating the black tank is full so.......it will not flush! How can I override the tank sensor reading from the toilet?

Many thanks for your help.

NEWMARDS3724 · 07-17-2017, 12:47 PM

Quote:

Originally Posted by cgarringer

Our black tank is empty but the sensor shows full. We know it is empty. Therefore, our Masterflush 8700 toilet is also showing a red light indicating the black tank is full so.......it will not flush! How can I override the tank sensor reading from the toilet?

Many thanks for your help.

I had something similar happen to me as well except it was the yellow (half full) indicator. Mine went off after I flushed it following retreatment of the tank so I'll be interested in the finding from the professionals on here...

Capt. Kirk · 07-17-2017, 12:51 PM

Do you have a Digi Level in your passenger side overhead cabinet? If you do, press the SELECT button and cycle through the tank level and battery voltage readings. That clears my warning lights and the flushers resume operation.

NEWMARDS3724 · 07-17-2017, 01:00 PM

Quote:

Originally Posted by Capt. Kirk

Do you have a Digi Level in your passenger side overhead cabinet? If you do, press the SELECT button and cycle through the tank level and battery voltage readings. That clears my warning lights and the flushers resume operation.

I think that's what cleared mine as well. Great point

cgarringer · 07-17-2017, 03:02 PM

The problem is that our tank sensor is reading full when it is not. Back flushing the tank is not possible at our current campground. There is probably some debris causing the sensor to read full. I was hoping that there was an easy way to disable the sensor reading on the toilet.

cgarringer · 07-17-2017, 03:52 PM

This hasn't cleared it. I think the problem is that our tank sensors need to be cleaned. We are not in a place right now where we can back flush so I am trying to find a way to over ride the Dometic Macerator toilet "red light" so that we can flush it.

dms · 07-17-2017, 06:11 PM

Had this problem a while back. Locate the small black toilet control box, usually under the cabinet on a wall. Locate the yellow wire and cut it. Leave enough room when you cut to install a switch or to re-splice it after you clean the tank later.

The yellow wire is the "tank full" sensor wire and completes the circuit when the tank is full. By cutting it (open circuit), it tells the control box that the tank is not full, and your toilet will flush normally. Just remember that you have disabled the "tank full" sensor, thus watch your tank level very closely to avoid an overflow disaster.

I installed an on/off toggle switch on mine in the event it ever happens again.

cgarringer · 07-18-2017, 05:08 AM

Quote:

Originally Posted by dms

Had this problem a while back. Locate the small black toilet control box, usually under the cabinet on a wall. Locate the yellow wire and cut it. Leave enough room when you cut to install a switch or to re-splice it after you clean the tank later.

The yellow wire is the "tank full" sensor wire and completes the circuit when the tank is full. By cutting it (open circuit), it tells the control box that the tank is not full, and your toilet will flush normally. Just remember that you have disabled the "tank full" sensor, thus watch your tank level very closely to avoid an overflow disaster.

I installed an on/off toggle switch on mine in the event it ever happens again.

That sounds like the answer except we cannot find the control box! Have looked in all the bays under the rear bath. Nowhere in bathroom. We have a 2016 Ventana with rear bath. Any ideas?

ravensdad · 07-18-2017, 08:46 AM

Our toilet control box is behind the pegboard panel in water bay on passenger side.

cgarringer · 07-18-2017, 08:52 AM

Thank you. Will try there. I just spoke with Dometic and the confirmed that you can disconnect the yellow wire in the control box. Now to find it!

cgarringer · 07-18-2017, 09:48 AM

MYSTERY SOLVED! After all else failed....We called Newmar Customer Service to see if they could tell me where the Dometic Control Box was located. That took some time. The techs knew that it had to be within 6 feet of the toilet and that it had to be inside the living area, not in a bay. Turned out that it was behind a false panel below the washer and dryer closet. What kept us from looking there was that that panel is nailed on....no easy remove clips. My husband pried the nails out and...Wa-La...there it was. We clipped the yellow wire and Flushed!