pmmi water/black/propane tank level gauge/ outside temp sens
the pmmi panel that is above the microwave is my challenge. the clean water tank reads half full when it is full. the black tank reads a third when it is empty and the propane tank reads lower than it is. the bay temp is ok and the outside temp reads an error.
i took the panel out and shipped it to pmmi. doug cleaned and calibrated the panel and says the outside temp should work and the propane was out of calibration. the clean and black water calibration was ok.
he is sending me the wiring diagram of the two plugs on the panel so i can make sure the wires are ok.
there are 5 probes on each tank. they are like ohm meters. the bottom probe is a common and the other probes are at the levels displayed on the gauge. the water completes the circuit between the common on the bottom and the probe where the water level is.
on the clean water tank doug says there is usually no scum to goof it up. so it is either a malfunctioning probe (which he thinks is probably not the problem) or a wire off etc. so that will be easy enough to check.
on the black water tank he says there is always scum buildup over time that prevents the sensor from reading right. so, if the wiring is ok...then either clean the tank/probes or replace them. they are only 8 bucks apiece so replacing them is not a big deal other than the work. i have to go check the access cause i have not yet.
so my question is this....do any of you have the same issues and if so what have you done to fix it?
how do you clean your black water tank to keep the probes clean? he suggested taking a pressure washer in the toilet hole and spraying the tank from the inside. i can get a 90 degree attachment for my pressure washer i know they use for spraying under cars in gutters etc and that should work. have any of you done that?
so, i am looking for the voice of experience.
also, where is the outside temp sensor located, anyone know?
i traced out the temperature sensors....they are black and white twisted pair wires of about 16 gauge. on mine, the external temp sensor wire runs across the top of the passenger side water tank bay to the next bay towards the front and then runs down the side and the sensor hangs out a hole to the bottom of the coach.
the water tank bay temp sensor is immediately below the hole where the wire comes down from above the floor. and is bundled on the drain pipes towards the top of the bay.