I have a 1977 Winnebago that I took on for a remodeling project. I am finally down to the monitor panel for the tanks. My holding tanks have sensors in the sides of the tanks and so does the fresh water tank. The panel has a switch for Tank 1, Tank 2 and the water tank. If I had a schematic for the printed circuit board I may be able to figure out what’s wrong since I am an electrical engineer and also an electronics technician. Since none of the tanks register properly, I’m suspecting the printed circuit board, but after reading comments by you and others there could be a low impedance reading between the sensors resulting in faulty readings on the panel. What would you suggest?
Raymond, (Pasco, WA)
Raymond, unfortunately back in those days, monitor panel suppliers used an assortment of circuit boards for their panels. Without knowing the manufacturer of the monitor panel itself, it would be difficult, if not impossible, to obtain the correct schematic. In addition, most panels were produced with the logo of the RV manufacturer and not the actual board maker. Compounding this, most board makers from that decade are now out of business.
The good news is that newer, more sophisticated, (and more accurate), monitoring systems are now available. All would have to be obtained through a RV service facility or parts store. I would recommend one that does not rely on well nuts (sensors) mounted through the tank walls. I favor those that are affixed to the outsides of each tank, thereby, eliminating the inevitable false readings that will occur with well nuts.
Check out the SeeLevel monitoring system produced by Garnet Technologies, www.rvgauge.com. Their tank sensors are incorporated into a single, flexible circuit board, fitted to the exterior of the tanks. One side of the flexible board contains the transmitter and the other side holds the segmented receivers. All this means is that the signal from the sensors is digitized and the readout on the monitor panel shows the percentage of how full each tank truly is – to within an accuracy of 2%. Quite an improvement over systems using levels indicated by each quarter or third segment of the tank.