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Troubleshooting & Installation Tips
What to do if the system freezes or is unresponsive
If the display is unresponsive, it may be "hung" due to a static discharge or electrical
noise. Try rebooting it by shutting off the 12V power to it for a few seconds, then
turning it back on.
What to do if operation becomes erratic or stops completely
Make sure all wiring connections are solid. Do not use spade connectors to join
wiring as they will degrade over time. Use insulated crimp-on butt connectors or
solder and insulate the wire connections.
What to do in dual console systems if the two displays do not read the same
For dual display console applications, if the consoles disagree the most likely
reason is a bad console ground. Both console grounds, and the sender grounds,
must be connected together with ground wiring. Do not depend on metal chassis
components. See item 2 in the following section for further details.
What to do if readings jump or are inaccurate
1.
We have had a few instances where 120VAC interference has caused the
readings to stall and create a gap; readings would skip from 50% to 70% and
then begin to function again. The cause was wiring between consoles and
senders being tied too close to entrance boxes for shore power or bundled with
other high AC voltage lines or junction boxes.
2.
Always ground the senders and the console to the same ground circuit. This is
very important; RV's can have several ground circuits with resistance between
them. We have had instances where two consoles are installed with a different
ground for the service bay console and interior console. If you see different
levels from each console on the same tank, then the ground circuit is not
common. Connect both consoles to the same ground back to the breaker
panel ground point.
What to do if the system indicates a residual or non-zero water level even
though the tank is drained completely
1.
This can be due to a convex tank bottom or a sloped tank bottom. In the case
of the convex bottom tank a ring of water may remain after draining. In the
case of the sloped bottom (to the drain valve side) a very small amount of
water left in the tank will result in a non-zero level indication. In both of these
cases, temporary installation of the sender using duct tape or masking tape will
allow the installer to check the tank level before committing to a final sender
position. After cutting the sender to length and connecting the wires, be
sure to tape down both sides of the sender to eliminate air gaps between the
sender and tank surface which can cause low signal strength and unpredictable
performance. The ends of the sender must be at least ¼" to ½" away from the
tank bottom and top to allow for wall thickness. The exterior bottom & top
of the tank are not the same as the interior bottom & top; depending on the
tank wall thickness the inside height is ½" to 1" shorter than the outside height.
Knowing the wall thickness of your tank will allow you to find the optimal
sender position; placing the sender where it can "see" the water will ensure
proper level calculation and sender operation.
SeeLeveL II 709 Series Display Manual
2.
The signal strength should be in the 50% range for best performance. If the
signal strength is in the 20% range it is indicative of a high resistance in a
connector, a bad ground, or improper bonding of the sender to the tank (a
possible air gap on one or both sides of the sender).
3.
With the console installed you can check the level on each tank, if you get an
indicated level of 10% to 20% and you know this is too high, reposition the
sensor board as follows:
NOTE: In the case of a convex tank bottom, usually found on large flat tanks,
W
raising the sender is the best solution to accomplish a zero reading when the
tank is empty. This may result in having to shorten the sender by an additional
segment.
On sloped tanks, which are used to promote complete draining, one alternative
is to measure the end of the tank opposite from the drain valve. It may be
necessary to extend the wire harness to be able to measure on the optimal side.
On the drain valve side, the best choice is to elevate the sender to avoid reading
a puddle at the drain valve.
4.
The close proximity of metal to the sender can be misinterpreted as water,
since they have similar electrical characteristics. Any metal such as steel,
aluminum, copper, or brass can affect the sender reading if it is closer than
about 2" from the face of the sender. If there are metal frame pieces, brackets,
straps, pipes, ducts, etc. close to the sender you may have to move the sender
away from them. Again, trial positioning using tape is necessary until the
problem disappears. Flexible pieces of metal can be held away from the sender
with rubber wedged between the sender and the metal. If the metal is off
to the side of the sender, or just butting to the edge then it is usually not a
problem, particularly on the right hand side of the sender.
5.
Make sure that metal doors or covers are far enough away from the sender as
well, once everything is closed up the positioning may change. The symptoms
of exposure to large metal components are usually a non-zero reading when
the tank is empty, or the level appearing to jump suddenly as the tank is
drained or filled.
6.
On fresh tanks there is sometimes a potential to not be able to use all the
water in the tank, we suggest you elevate the fresh sender 1" off the tank
bottom and position the top of the sender to allow for vent position (if the vent
is on the side of the tank). This way you should see '0' before the pump starts
to suck air. Some tanks have a sump style draw system, in this case there is no
concern with unusable water, just allow for the wall thickness when positioning
the sender board (usually ½" to 1" margin from the outer shell). If the sender is
positioned above the vent then the maximum reading may be less than 100%.
7.
There may be a buildup on the inside walls of black and grey tanks. We get
calls occasionally about older coaches that have not been in service for a few
years in which the black tank will now indicate a level even though it is empty.
The likely cause is that the tank has a significant build-up, probably exceeding
¼" to ½" thick! Redex is not an acceptable chemical to promote clean tank
walls; it is far too slow to get the breakdown action started. Use an RV type
of liquid chemical, we suggest Tissue Digester, Sensor Cleaner, or the latest
we have used called Happy Campers Holding Tank Extreme Cleaner available
at www.happycampersworld.com. The next time you take a trip, leave with
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Troubleshooting
