SEELEVEL II

TM

Tank Monitor

MODEL 709-DLP
MANUAL

IMPORTANT OPERATOR INFORMATION

DATE INSTALLED:______________________________________________________________

SERIAL NUMBER:______________________________________________________________

Signal Level Sender Height

Black Water Tank
Grey Water Tank
Fresh Water Tank

Printed in Canada

www.garnetinstruments.com
 GARNET TM
SEELEVEL II
Tank Monitor

MODEL 709-DLP

Table of Contents

CHAPTER 1 - OVERVIEW..............................................................................................3
CHAPTER 2 - SYSTEM DESCRIPTION......................................................................4
CHAPTER 3 - OPERATING INSTRUCTIONS...........................................................6
CHAPTER 4 - DISPLAY CALIBRATION......................................................................8
CHAPTER 5 - SENDER PROGRAMMING.............................................................. 13
CHAPTER 6 - INSTALLATION GUIDE...................................................................... 17
CHAPTER 7 - TROUBLESHOOTING GUIDE.......................................................... 24
CHAPTER 8 - SPECIFICATIONS................................................................................ 32
CHAPTER 9 - SERVICE AND WARRANTY INFORMATION............................. 33
MAIL IN WARRANTY .................................................................................................. 35

709-DLP Manual_v4.4.1 - 23-Dec-2016

Page 2 709-DLP Manual

 CHAPTER 1 - OVERVIEW

T he SEELEVEL II TM Tank Monitor represents a massive leap

forward in level measurement technology for the Recreational
Vehicle industry. The SeeLeveL has a combination of features,
accuracy, reliability, and diagnostic capability that have never been
available before.

Model 709-DLP will monitor the battery voltage, the fresh water
and sewer holding tanks, two LP gas tanks and includes a pump
switch. The information is displayed on a 3-digit alpha-numeric
LED display. In addition, the system can display the operating
characteristics of each of the tank sending units, giving it
unsurpassed diagnostic capability.

WARNING: All power circuits must be fused. If a fuse

is not provided with the system then it is the installer’s
responsibility to install a fuse with a maximum rating of 10
amps. A relay is required if more than 10 amps is needed for
the pump.

For more detailed information please refer to Chapter 7

“TROUBLESHOOTING GUIDE” and section “How to avoid
damaging the display or pump switch due to excessive
current”.

709-DLP Manual Page 3

 CHAPTER 2 - SYSTEM DESCRIPTION

T he SeeLeveL consists of a display unit that mounts inside the RV,

and sender panels that stick to the side of the holding tank. A
single 2 conductor wire is used to connect all the sender panels to
the display.

The Sender: Each sender panel is a flexible self-adhesive printed

circuit board which is adhered to the side of the holding tank. The
sender panel can be cut to length to match the height of the tank, and
it auto calibrates itself so that it can read from Empty to Full regardless
of the height of the tank. The sender scans the water level through
the tank wall using advanced digital techniques programmed into
the sender microprocessor. When the sender transmits the water
or sewer level information to the display, it sends a digital code that
has built in error detection, making it highly unlikely for the display
to read an incorrect level, even if the wiring is marginal. In addition
to the level, the sender also transmits diagnostic information about
its operation. This information can be used to determine if there
is buildup of sludge on the inside of the tank, or to determine if
the sender is damaged or delaminating from the side of the tank.
If sludge buildup in the tank becomes extreme the gauge will cease
to operate properly, so by monitoring the signal power the tank can
be cleaned before the buildup gets excessive. Three different sender
options (710JS, 710ES, and 710SS) and the ability to double stack
the senders provide accurate level measurement for tank heights
ranging from 41/2” to 34”.

The Display: The display receives the information from the three
sender panels via a single 2 conductor wire, and displays the level
information in percent of full on a 3-digit LED display. When the
button for a particular tank is pressed, the display shows the level for
that tank. If the button is pressed and released, the display will show
the level for about 5 seconds and then shut down automatically. If
another button is pressed before the display shuts down, then the new
level will immediately be shown. If the same water or waste button
is pressed twice, the display will hold on that tank and continue to
show updated levels for 5 minutes before shutting off. This allows
the user to monitor the filling or draining of a tank. By pressing two
buttons at once, the diagnostic functions can be accessed; these are
described in detail in the troubleshooting chapter.

If a sender is operating properly and connected to the display with

good wiring, then the display will show the level normally. If the
wiring is disconnected, shorted, or cut, or if the sender panel is
defective, then the display will indicate an error code. The various
error codes are shown in the troubleshooting chapter.

Page 4 709-DLP Manual

 With these diagnostic features and the digital nature of the tank
level sensing technology, it is almost impossible for the system
to indicate an incorrect water level, and in the very unlikely
event it does occur, servicing is greatly aided with the diagnostic
information.

The system also shows the RV battery voltage by measuring the

voltage which powers the display. The voltage is shown with a
resolution of 0.1 volt.

The display can use existing LPG electrical senders to show two
LPG levels. When the LPG button is pressed the first time, the
LPG1 level is shown. If the LPG button is pressed again before the
display shuts down, the LPG2 level is shown, as indicated by the
decimal. Each time the LPG button is pressed while the display is
on will alternate between the two LPG values.

The display can be calibrated separately to any two LPG senders

and shows the level on the display in percent of full, from 0% to
100%.

In order to keep the tank level information current, the display

regularly scans the senders every 10-15 seconds. When a tank
button is pressed, the information displayed is recalled from the
most recent scan. A tank on hold is scanned more frequently.
Systems with two displays are configured so that the primary
display initiates the scanning and the secondary display passively
listens to the sender information, this way both displays stay
updated without interfering with each other.

709-DLP Manual Page 5

 CHAPTER 3 - OPERATING INSTRUCTIONS

T he display is the only system component that is accessed by

the user. All user input to the display is done using the five
buttons along the bottom of the display. Operation of the display
is as follows:

To read a water or sewer tank level:

1. Press the button corresponding to the tank to be checked and

release it, the display will show the level in percent on the LED
display. If no other button is pressed, then the display will
shut off after about 5 seconds.
2. If another button (including BATT or LPG) is pressed before
the 5 second time is up for the first button, the display will
immediately switch to showing the new level or voltage. The
5 second timeout is restarted every time a button is pressed.
3. To continuously display a reading, press and release the
desired button, and then press the same button a second
time. When the button is released, the display will be in hold
mode, which is indicated by the decimal point on the right
hand side turning on. While the display is in the hold mode
it will recheck the held level every 2 - 3 seconds so the user
can watch the level change while the tank is being filled or
drained. The other tanks will continue to be scanned every
10 - 15 seconds. The display will automatically shut off after
5 minutes in hold mode. To end the hold mode before the 5
minutes is up, press any tank button, and the display will shut
off.

To read the LPG tank levels:

1. Press the LPG button and release it, the display will show the
LPG1 level in percent on the LED display. If no other button is
pressed, then the display will shut off after about 5 seconds.
2. If the LPG button is pressed again before the display shuts off,
the display will show the LPG2 level, indicated by the decimal
point. Each time the LPG button is pressed while the display
is on, the display switches to show the other LPG tank level.
The 5 second timer will be restarted each time the button is
pressed.
3. If another button is pressed before the 5 second time is up
for the LPG button, the display will immediately switch to
showing the new level or voltage. The 5 second timeout is
restarted every time a button is pressed.

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 4. There is no hold mode for the LPG. The decimal point indicates
that the level shown is for the LPG2 tank, it does not indicate
hold. The LPG tank level cannot change fast enough to justify
the use of the hold function, except during filling of the tank.
The gauge should not be used as a full tank shutoff indicator
since the LPG sender in the tank is not reliable or accurate
enough to be used as a safe indicator of a full tank.
Note: If using two displays (i.e. a primary and a secondary
display), then only the primary display should have connections
to the LPG tanks. If both displays are connected to an LPG
tank, then an incorrect reading will result. The primary display
relays LPG levels to the secondary display through the sender
wiring to the secondary display.

To read the battery voltage:

1. Press the BATT button and release it, the display will show the
battery voltage on the LED display.
2. If no other button is pressed, then the display will shut down
after about 5 seconds. If the BATT button is held down,
the display will continuously recheck the voltage and show
the updated value. The reading may flicker back and forth
between two values, for example, 12.6 and 12.7 volts. This is
normal behavior for a digital voltage display.
3. If another button is pressed before the 5 second time is up
for the BATT button, the display will immediately switch to
showing the value for the new button. The 5 second timeout
is restarted every time a button is pressed.
4. There is no hold mode for the battery voltage.

709-DLP Manual Page 7

 CHAPTER 4 - DISPLAY CALIBRATION

To calibrate the LPG senders:

1. The LPG tank must be full when the sender is calibrated,

otherwise the calibration will be invalid. Fill the LPG tank by
using an alternate measurement method, such as weight, a
spit valve, or a mechanical gauge on the tank. Each tank will
have to be calibrated separately.
2. To calibrate the first tank, press and hold down the LPG
button, the display will show some LPG level.
3. While continuing to hold down the LPG button, press and
hold down the BATT button. Continue to hold down both
buttons for about 10 seconds until the display shows “LP1”.
4. When this occurs release both buttons, the display will show
“CAL” for a couple of seconds and then shuts off, completing
the calibration procedure. The LPG can be recalibrated as
many times as desired, although recalibration should not be
needed unless the LPG tank sender or the display has been
replaced.
5. To calibrate the second tank, repeat steps 2 - 4 except wait for
15 seconds instead of 10 until the display shows “LP2”.
Note: If the buttons are held down for an additional 5 seconds
after showing “LP2”, the display will show “ESC”, this escapes
the calibration process and prevents any changes from being
made.

To program the LED brightness:

1. If the display is to be used inside the coach, the LED brightness

should be low. If it is to be used in the service bay area where
sunlight can reach it, the LED brightness should be high.
2. To program the LED brightness, the display needs to enter
the brightness programming mode. To do this, press and
hold down the BATT button, the display will show the battery
voltage.
3. While continuing to hold down the BATT button, press and
hold down the GREY button. Continue to hold down both
buttons for about 5 seconds until the display shows “bri”
to indicate the brightness programming mode. When this
occurs release both buttons.

Page 8 709-DLP Manual

 4. The display will now indicate the brightness that is currently
programmed by showing “b-1”, “b-2”, “b-3”, or “b-4”, where
“b-1” is the minimum brightness and “b-4” is the maximum
brightness.
5. Press the GREY tank button to increase brightness, or the
FRESH tank button to decrease brightness.
6. When the display shows the correct brightness, press the
BATT button to exit the programming mode.

To program the number of senders for each tank:

1. To program the number of senders for each tank, the display

needs to enter the sender programming mode. This should
only be done at the time of installation; there is no reason
to change the number of senders afterward. Make sure that
the number of senders programmed into the display matches
with the number of senders connected; otherwise the display
will show an error.
2. To enter the sender programing mode, press and hold the
button for the tank to be programmed, the display may show
a level or an error message for that tank.
3. While continuing to hold down the button for the tank, press
and hold the BATT button. The display will immediately show
”dIA” (diagnostics), continue to hold down both buttons until
the display enters the programming mode, this should take
about 10 seconds.
4. When the programming mode is entered, the display will
show “FrS” if entering the number of senders for the fresh
tank, “GrS” if entering the grey tank, or “bLS” if entering the
black tank. When this occurs release both buttons.
5. The display will now show “0SE” (zero senders/disabled),
“1SE” (one sender) or “2SE” (two senders), based on what is
currently programmed into the display. These are the only
three options; the display will not work with more than two
senders per tank.
6. To change the number of senders, press the tank button, each
time the button is pressed the display will increment one
number.
7. When the display shows the correct number of senders, press
the BATT button to exit the programming mode. Each tank
will need to be calibrated individually using this procedure.

709-DLP Manual Page 9

 To program the alarm set points for each tank (FRESH/GREY/
BLACK/LPG1):

Note: There are no alarm outputs on this 709 version. The alarm
menu is still present for consistency but has no function.

1. To program the alarm point for each tank, the display needs
to enter the alarm programming mode. There is no alarm for
the LPG2 tank.
2. To enter the alarm programming mode, press and hold down
the button for the tank to be programmed, the display may
show a level or an error message for that tank.
3. While continuing to hold down the button for the tank, press
and hold down the BATT button. The display will immediately
show ”dIA” (diagnostics), continue to hold down both buttons
until the display enters the alarm test menu, this should take
about 5 seconds. The LPG tank does not show “dIA”.
4. When the alarm test menu is entered, the display will show
“ALr” for about 5 seconds. Release both buttons.
5. Depending on which tank is selected and the status of the
alarm, the display will show a simulated low fluid level below
the alarm set point (FLo, GLo, bLo, LLo) or a high level above
the alarm point (FHi, GHi, bHi, LHi). The alarm test menu
allows the alarms to be manually activated to test. The same
tank button toggles the simulated fluid level between low and
high.
6. To set the alarm point, press and hold the same tank button,
after about 3 seconds, the display will show “FAS”, “GAS”, or
“bAS”, “LAS”, depending on which tank is selected. Release
the button.
7. To set the alarm point, the GREY button increases the value,
the FRESH button decreases the value, the BLACK button
toggles the trip polarity and the LPG button toggles the
failure polarity. The BATT button saves and returns to the
previous menu. The alarm point can be from 0% to 99%. If
the FRESH or GREY buttons are held down, after 1 second the
numbers will change quickly.

Trip Polarity: While the BLACK button is held down, the display
shows “Hi” for a high level alarm or “Lo” for a low level alarm.
After the button is released, the left digit shows “H” for a high
level alarm which means the alarm turns on (closes) when the fluid
level is equal to or higher than the set point, and the alarm is off
(open) when the fluid level is below the set point. An “L” shows a
low level alarm which means the alarm turns on (closes) when the

Page 10 709-DLP Manual

 fluid level is below the set point, and the alarm is off (open) when
the fluid level is equal to or above the set point.

Failure Polarity: While the LPG button is held down the display
shows “FtF” for fail to full, or “FtE” for fail to empty. After the
button is released, the display shows: Left decimal on shows fail
to full which means that if the sender fails the alarm acts as though
the tank is full. Left decimal off shows fail to empty which means
that if the sender fails the alarm acts as though the tank is empty.

To program the display as primary or secondary:

An optional second display can be added to the system. This allows

for a display in the service bay and one inside the coach. To avoid
reading errors when using dual displays, one display needs to be
set to secondary mode. A display in secondary mode monitors
the primary displays sender requests and will only scan the tank
levels at a much slower rate if the primary display is disconnected.
The alarms are inactive on the secondary display.

To program a display to be either primary or secondary display:

1. Press and hold the BATT and FRESH buttons while powering
up the display.
2. The display will show “Scn” for 5 seconds, then change to
“SEC” or “Pri” depending on current programming.
3. The FRESH button sets the mode to PRIMARY, the GREY
button to SECONDARY and the BATT button saves and exits.

Note: The battery voltage is calibrated at the factory; this should

never need to be changed.

To check the primary/secondary mode:

1. Press and hold down the BATT button, the display will show
the battery voltage. While continuing to hold down the BATT
button, press and hold down the BLACK button. Continue to
hold down both buttons for about 5 seconds until the display
shows “Pri” for primary mode or “SEC” for secondary mode.
When viewing is complete, release both buttons to return to
normal operation.

709-DLP Manual Page 11

 To check the hardware and software revision:

1. Hardware and software updates may be periodically released

to add features. To check the hardware and software version
of the display, use the following procedure.
2. Press and hold down the BATT button, the display will show
the battery voltage. While continuing to hold down the BATT
button, press and hold down the FRESH button. Continue to
hold down both buttons for about 5 seconds until the display
shows a number such as “4.10”, the first number is the
hardware version and the last two numbers are the software
version. When viewing is complete, release both buttons to
return to normal operation.

Page 12 709-DLP Manual

 CHAPTER 5 - SENDER PROGRAMMING

To program the 710ES or 710SS sender for the correct tank:

1. Since the senders are all connected in parallel to save wiring

and to simplify installation, the senders must be programmed
so they know which tank they are on. The senders can be
programmed for either the fresh, grey, or black tank. This is
done with the two tabs on the top corners of the sender. See
the following diagram.
2. The senders default to fresh tank operation if the programming
is not altered. Consequently, if the sender is for the fresh tank,
nothing further needs to be done to it.
3. If the sender is for the grey tank, remove the tab that says
“GRY” next to it.
4. If the sender is for the black tank, remove the tab that says
“BLK” next to it.
5. This is all that is required to program the senders for the
correct tank. However, if you make an error, you have one
chance to correct it, as described below.
6. If the “GRY” tab has been removed and it should be a black
tank sender, or if the “BLK” tab has been removed and it
should be a grey tank sender, then cut out the recessed grey-
black correction tab that says “GBC” next to it. This reverses
the effect of the grey and black tabs.
7. If either the “GRY” or “BLK” tabs have been removed and it
should be for a fresh tank, then remove the other “GRY” or
“BLK” tab. When both the “GRY” and “BLK” tabs are removed,
it is equivalent to neither of them being removed.
8. If the sender is single, no further programming is required.
9. If double stacked senders are used, the top sender must have
additional programming, as described below.
10. Refer to the 710ES and 710SS sender programming diagram.

To program the 710ES or 710SS sender as top or bottom:

1. Since the senders are all connected in parallel to save wiring

and to simplify installation, the senders must be programmed
so they know whether they are a single, top, or bottom sender.
This is done with the tab at the top center of the sender. See
the following diagram.

709-DLP Manual Page 13

 2. The senders default to single or bottom operation if the
programming is not altered. Consequently, if the sender is for
single or bottom operation, nothing further needs to be done
to it (beyond programming it for the correct tank).
3. For a top sender, remove the tab that says “TOP” next to it.
4. This is all that is required to program the senders for single,
top, or bottom use. However, if you make an error, you have
one chance to correct it, as described below.
5. If the “TOP” tab has been removed and it should be a single
or bottom sender, then cut out the recessed top correction
tab that says “TC” next to it. This reverses the effect of the
top tab.
6. Verify that both the top and bottom senders have been
programmed for the correct tank.

To program the 710JS sender for the correct tank:

1. Since the senders are all connected in parallel to save wiring

and to simplify installation, the senders must be programmed
so they know which tank they are on. The senders can be
programmed for either the fresh, grey, or black tank. This is
done with the two tabs on the top corners of the sender. See
the following diagram.
2. The senders default to fresh tank operation if the programming
is not altered. Consequently, if the sender is for the fresh tank,
nothing further needs to be done to it.
3. If the sender is for the grey tank, remove the tab that says
“GRY” next to it.
4. If the sender is for the black tank, remove the tab that says
“BLK” next to it.
5. This is all that is required to program the senders for the
correct tank. However, if you make an error, you have one
chance to correct it, as described below.
6. If the “GRY” or “BLK” tab has been removed by mistake, the
sender can be changed to a fresh tank sender by cutting the
other corner tab (“BLK” or “GRY”).
7. Refer to the 710JS sender programming diagram.

Page 14 709-DLP Manual

 710ES AND 710SS SENDER PROGRAMMING

709-DLP Manual Page 15

 710JS SENDER PROGRAMMING

Page 16 709-DLP Manual

 CHAPTER 6 - INSTALLATION GUIDE

1. Please refer to the “Troubleshooting and Installation Tips”

section in Chapter 7 for details on avoiding installation issues.
2. The installation consists of mounting the display inside the RV,
cutting and fastening the senders to the sides of the holding
tanks, connecting wiring, and programming the display. When
wiring DO NOT use spade connectors to join wires, only use
crimp on butt connectors or solder the wires together.
3. Mount the display by cutting a hole in the wall 3” wide by 1 7/8”
high and bringing the wiring out through the hole to connect
to the display panel connector.
4. Connect the wiring according to the following table. It is
easier to connect the wiring to the display connector first, and
then plug the connector into the display panel. The senders
need to be grounded to a single ground wire from the display.
Make sure that the system ground is connected to the breaker
panel ground.
Wire Colours on Connector

Wire Color Function

White 18 gauge Pump LED
Red 18 gauge +12V
Black 18 gauge Ground
Blue 18 gauge Tank Senders
Green 18 gauge LPG1 tank
Green/Yellow 18 gauge LPG2 tank

5. Determine where to mount the senders on the tanks. They

will need to have a flat area on the side of the tank large
enough so the whole width of the sender is in contact with
the side of the tank, all the way from the top to the bottom of
the tank. Make sure that any metal is at least an 1” away from
either side or the top and bottom of the sender, and at least 2”
away from the face of the sender. Clean the area well so that
there is no dust, grease, oil, water, etc., that would prevent the
adhesive on the sender from sticking.
6. Measure the height of the tank to determine which sender
configuration to use and how long the senders should be.
Refer to the following table. Note: DO NOT mix sender types
when stacking senders.

709-DLP Manual Page 17

 Tank Sender Options
Height Best Resolution Other Acceptable
41/2” - 5” JS -
5” - 7” JS ES
7” - 13” ES SS
13” - 17” stacked ES SS
17” - 25” stacked ES stacked SS
25” - 34” stacked SS -

For single sender applications:

The sender ends should be 1/4” to 3/4” away from the top and
bottom of the tank, to allow for the thickness of the tank top and
bottom and any bows in them (see the diagrams). The senders
are calibrated to account for this distance from the bottom of the
tank. The SS sender is cut to the nearest even 2” in length. The ES
sender is cut to the nearest even 1.5” in length, for example, for a
system with a tank height of 11.75”, cut the sender to be 10.5” long,
this allows 5/8” at each end when the sender is centered vertically
on the tank. The JS sender is cut to the nearest 1.0” in length.
IMPORTANT: DO NOT cut the 710SS sender shorter than 6”. This
sender will not work if it is cut shorter than 6”. DO NOT cut the
710ES sender shorter than 41/2”. This sender will not work if it is cut
less than 41/2”. DO NOT cut the 710JS sender shorter than 4”. This
sender will not work if it is cut less than 4”.

For double stacked sender applications:

For tall tanks, two stacked 710ES or 710SS senders are used. The
sender ends should be 1/4” to 3/4” away from the top and bottom of
the tank, to allow for the thickness of the tank top and bottom and
any bows in them (see the diagrams). The senders are calibrated
to account for this distance from the bottom of the tank. In
addition, there needs to be a gap of 1/16” to 1/8” in between the
two senders. Therefore the total length of both senders will be:
tank height -1/4”-1/4”-1/8”, then rounded down to the nearest 1.5” (ES
sender) or 2” (SS sender) . The top and bottom senders should be
approximately the same length for best results. For example, if the
tank height is 22”, then 22”-1/4”-1/4”-1/8”= 21 3/8”, so the total length
of both ES senders will be 21”. Make both senders 10.5” long.

7. To make the senders the right length (assuming they are too
long) they will need to cut off with a pair of scissors. The
end to be cut is the bottom end, which is the opposite end
from the top where the wires come out (see the diagrams).

Page 18 709-DLP Manual

 710ES AND 710SS SENDER

709-DLP Manual Page 19

 710JS SENDER

Page 20 709-DLP Manual

 DO NOT cut the sides, and DO NOT cut the 710ES sender
shorter than 4 1/2”, the 710SS sender shorter than 6” or the
710JS sender shorter than 4”. The cut must be in between the
sensor pads, and the cut must be made parallel to the existing
bottom end. Double check your measurements, if the sender
is cut too short, it cannot be lengthened.
8. The senders need to be programmed so they know which tank
they are on. This is done by selectively cutting off the tabs
on the top of the sender. See the chapter entitled “SENDER
PROGRAMMING” for details.
9. For double stacked sender systems, the senders also need to
be programmed so they know whether they are being used
as top or bottom senders. See the chapter entitled “SENDER
PROGRAMMING” for details.
10. Once the sender is cut to length and programmed, do a test
by taping the sender to the tank wall. Make sure there are no
air gaps between the sender and the tank. Verify operation
before permanently sticking the sender to the tank wall.
Once proper operation has been confirmed, carefully peel the
backing paper off the adhesive. Do this slowly to prevent the
adhesive from being ripped off the sender, and to prevent
the backing paper from ripping. Be careful not to bend the
sender sharply in the process. Position the sender over the
side of the tank and carefully stick it down. MAKE SURE THAT
THE END WITH WIRES IS POINTING UP!! Position the bottom
of the sender at least 1/4” above the bottom of the tank, or
slightly higher if required to equalize the space at the top and
bottom of the tank. Make sure that the sender is square with
the tank. You only have one shot at this, if you try to peel it off
the tank once it is stuck the sender may be damaged by the
sharp bending. Carefully press the sender down to the tank
so that all of the adhesive is contacting the tank wall.
11. Do steps 5 to 10 for the other two holding tanks.
12. Connect all the blue wires from the senders together, and to
the blue wire from the display. Connect the black wire from
each sender to ground at the display. It is very important
that the display and the senders have the same ground. Use
crimp on butt connectors to fasten the wires together. Make
sure that the wires from the sender are routed to the RIGHT
side of the sender, away from the sender. NEVER route the
wires to the left of the sender. If they drape over the sender
they could affect the reading. Secure the wires with tie wraps
or something similar so that the wires do not rattle or press
against the sender, this may result in sender damage or wires
breaking over time. Refer to the enclosed wiring diagrams.

709-DLP Manual Page 21

 13. Connect the green wire from the display to the sender from
LPG tank #1. Connect the green-yellow wire from the display
to the sender from LPG tank #2. Make sure that the ground
from both senders is connected back to the display ground or
to the breaker panel ground.
14. All that remains now is calibration and testing. The tank
senders will self calibrate to whatever length they are cut, so
they will always read from 0% to 100%. The display needs
to be set to a single or double sender system for each tank.
See the chapter entitled “DISPLAY CALIBRATION” and the
section “To program the number of senders for each tank”
for details. Make sure you do it for each tank.
15. For the initial test, have the tank at least 1/4 full of water or
sewage, and verify that the percent level reading looks correct
(see the chapter entitled “OPERATING INSTRUCTIONS”
and the section “To read a water or sewer tank level” for
details). Check to see that the signal power is at least 20%
(see the chapter entitled “TROUBLESHOOTING GUIDE”
and the section “To review the sender diagnostics” for
details). If the signal power is too low, make sure that the
sender(s) is well stuck to the side of the tank and that the
tank is reasonably clean inside, as a large buildup will reduce
signal strength. The gauge will work with maximum signal
strengths as low as 20%, but it is good to have at least 50% to
60% at installation so that there is some margin available for
buildup in the tank. Note that the system “learns” about the
characteristics of the tank with use, so the readings may be
inaccurate when the tank is empty or almost empty when the
system is first tested. Once the tank has been filled at least
1/4 full the system will be properly “taught” and should read
correctly after that.
16. Calibrate both LPG tanks by filling both of them and
following the instructions in Chapter 4 entitled “DISPLAY
CALIBRATION” and the section “To calibrate the LPG
senders”. Both calibrations do not have to be done at the
same time. Just ensure that the tank being calibrated is full
when the calibration is done.
17. If equipped, connect the pump switch as required.
WARNING: The pump switch is rated for a maximum
of 10 amps. The use of a relay is required if more than 10
amps is needed. A 10 amp (max) fuse must be installed in
the series with the 12V power circuit to the switch!
18. Verify that the battery voltage reads correctly. If it appears
low, make sure you have good wiring for the 12 volt power
and the ground.

Page 22 709-DLP Manual

 Typical Double Stacked 710ES or 710SS Sender Installation

709-DLP Manual Page 23

 CHAPTER 7 - TROUBLESHOOTING GUIDE

Display trouble codes:

If a sender or its wiring is not operating properly, the following

codes are shown on the display:

1. If a sender is unresponsive or there is an open circuit in the

wiring so that the sender is not connected, the display will
indicate an open circuit by showing “OPn” on the LED display.
2. If a sender is shorted or there is a short in the wiring, the
display will indicate a short circuit by showing “Sht” on the
LED display.
3. If a sender is sending bad data, there is damaged wiring, or if
there is electrical interference, the display will indicate a data
error by showing “Err” on the LED display. Also, if the senders
have not been programmed correctly, they can interfere with
one another and result in “Err” on the LED display. Check all
the senders to make sure they are programmed correctly. If
they are, replace the sender that is creating the error.
4. If the display has been programmed for a single sender, and
double stacked senders have been connected, the display will
show “StA”. In this case, change the senders or reprogram the
display as required. If only a top sender has been connected,
the display will show “nbo”, indicating that no bottom sender
has been received. If the tank should only have a single
sender, correct the programming on the sender, it should not
be a top sender.
5. If the display has been programmed for double stacked senders
for tall tanks, and only the bottom sender is working and the
top one is not, then the display will show “ntP” indicating that
no top sender is being received. If the top is working but no
bottom sender is being received, then the display will show
“nbo”. If neither sender is working, then the display will show
“OPn”. Check the wiring and the programming of the senders.
If all is OK with that, replace the bad sender.
6. The display contains a permanent memory which is used to
store the programming for battery voltage calibration value
and the tank sender signal levels. These signal levels are used
to help the system adapt to the tanks, which increases sender
accuracy at low tank levels. If this memory should fail, “CAL”
will be flashed on the LED display, indicating a calibration
failure. It will be necessary to replace the display if this occurs.

Page 24 709-DLP Manual

 7. The only diagnostic code available for the LPG sender is the
open circuit indication “OPn”. If the wiring to the LPG sender
is shorted then the LPG reading will always show “0”.
8. There are no diagnostics for the battery voltage.

The diagnostics can be used to check the wiring and the

senders:

1. If a short circuit is showing, disconnect the senders one at a

time at the sender location. If the short circuit indication goes
away when a sender is removed, then that sender is bad. If all
the senders are removed but a short circuit still shows, then
the wiring may be shorted. Disconnect the sender wire at the
display, the short indication should go away. If it doesn’t, the
display is bad.
2. If an open circuit for all the senders is showing, it is most likely
a wiring open circuit or display failure, since it is unlikely that all
three senders are bad. Try shorting the wiring together at the
display, the display should indicate a short circuit. If it doesn’t,
the display is bad. If it does, then remove that connection and
short the wires together at the sender locations. If no short
circuit is shown, then the wiring is open. If the display does
show a short circuit, then the senders must be bad.
3. If a single sender is showing an open, try shorting the wiring
together right at that sender. If a short now shows, the sender
is bad or not wired properly. If no short circuit shows on the
display, the wiring to that sender is open.

To review the sender diagnostics:

1. The sender diagnostics can be reviewed periodically to check

for any degradation of the tank senders. If a sender appears
to be malfunctioning, reviewing the diagnostics should be the
first step in the troubleshooting process.
2. There are two diagnostics for the senders: the signal power,
and the sender height.
The signal power is an indication of how much signal is being
transmitted through the tank wall and picked up by the receive
part of the sender. If the signal power is too low, it can indicate
a sender which is detached from the tank, excessive buildup
on the inside of the tank, bad wiring to the sender, low battery
voltage, or a defective sender. Typical signal power should be
50% to 60%. The minimum signal power for proper operation
is 20%.
The sender height is the number of receive segments present
in the sender. To determine the length of the sender, multiply

709-DLP Manual Page 25

 the calibration by 2.0 (SS sender) or 1.5 (ES sender) or 1.0 (JS
sender) to get the length in inches. The senders always auto
calibrate to the length that they are cut, so this diagnostic allows
the user to confirm the length and to make sure that the auto
calibration is working properly.
3. To check the diagnostics, press and hold the button for the
tank to be checked, the display will show the level for that
tank.
4. While continuing to hold down the button for the tank, press
the BATT button. When the display shows ”dIA”, release the
buttons, the display will then change to showing the signal
power diagnostic. This is indicated by a “P” showing on the
left digit, for example ”P26” indicates a 26% signal power.
5. The signal power will show for 5 seconds. The display will
then change to showing the sender height. This is indicated
by a small “h” showing on the left digit, for example “h 6”
indicates that the sender has 6 receive segments, which is 6”
high for a JS sender, 9” high for an ES sender, or 12” high for
an SS sender.
6. After 5 seconds of showing the height, the display will shut
off.

TROUBLESHOOTING AND INSTALLATION TIPS

What to do if the system freezes or is unresponsive:

1. 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:

1. 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:

1. 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.

Page 26 709-DLP Manual

 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.
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).

709-DLP Manual Page 27

 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:
In the case of a convex tank bottom, usually found on large flat
tanks, 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

Page 28 709-DLP Manual

 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 a high concentration of the chemical in the
tank and approximately 30% full of fresh water. Hopefully
you can drive for 2-3 days allowing the tank levels to rise
through normal use. We recommend that you exceed the
level that you see the system report when the tank is empty.
After the sloshing and the soaking hopefully the build-up will
be flushed away when the tank is drained and flushed. If you
still have symptoms the treatment may required a few more
times. The waste did not build up on the tank wall in one day,
so it may not dissolve in one treatment! The build-up looks
like water to the system since it holds a significant volume of
water in the build-up area. It takes much more than a film or
piece of tissue to cause the error.

What to do if the system reads a zero water level at all times,

or does not reach 100%:

1. This may be due to excessive tank wall thickness. We have

tested the sender on an actual tank with 3/8“ wall thickness
to ensure proper operation. If you encounter an excessively
thick tank wall the symptom will be a zero reading regardless
of the actual tank level. The cross check would be to test
the sender on another tank by taping it in place temporarily,
if it now works the tank wall thickness is well over 3/8“. You
can also use a 1 gallon jug or a 5 gallon pail as a test tank to
crosscheck operation of the sender.
2. A symptom we have seen is the sender will not indicate 100%
when the tank is full. If the sender is positioned too high
on the tank, then water cannot reach high enough on the
sender for it to read 100%. The top of the sender must be at
least ¼” to ½” away from the top of the tank to allow for wall
thickness.
3. Another possibility is a tank wall thickness issue that may
occur at the corners or edges of the tank. This has not been
a common issue, and the only correction you can make is to
move the board slightly lower, away from the thick area.

709-DLP Manual Page 29

 What to do if sender delamination occurs:

1. We have had reports of the senders literally falling off the

tanks or showing serious delamination. This is likely caused by
a lack of tank surface preparation. Surface prep is very simple,
wipe the area to be adhered to with products like Pro Bond,
alcohol, or acetone. Do not use thinners because they leave
residues which attack the adhesive. Ambient temperatures
of less than 60°F or 15°C prevent the bonding agents in the
adhesive from working properly; use a heat gun to warm the
tank surface if necessary. Also be sure the surface is dry, again
a heat gun is the best way to dry the bonding area. Finally,
the surface of the tank must be smooth. The adhesive works
much better on smooth surfaces, if necessary use an orbital
sander with fine grit paper (220 grit) to quickly accomplish the
desired smoothness.
2. Another possibility is the wiring harness pulling on the sender.
Make sure the wiring to the tank sender is well supported so
that it does not put a load on the sender. Be sure to support
all connecting harnesses; do not let the board support the
harness, this will in time cause delamination of the board
from the tank. One simple way to do this is to use Gorilla
tape across the top of the sender at a 90 degree angle to the
sender orientation, with the wiring held in place by the tape.
The wires from the sender must be routed straight up or to
the right for reliable operation.

How to protect the sender from road spray and debris:

1. On installations where the holding tank is exposed to under

chassis road spray and flying rocks etc. we recommend the
use of an auto body undercoat, which is easily purchased in
auto parts stores. This tar based material clings well to the
senders and protects from water and debris.
2. One material in particular is 3M Professional Grade Rubberized
Undercoating, product code 03584. Another product that
works well is a Dominion Sure Seal rubberized undercoating
such as Gravel Guard Rocker Guard Coating.
3. After the system is completed and tested apply the undercoat
over the complete board using two coats. Do not use lacquer,
enamel paint, or plastic paint for auto bumpers as these
contain chemicals that will dissolve the conformal coating on
the board and cause malfunctions.

Page 30 709-DLP Manual

 How to avoid damaging the display when mounting:

1. If mounting the display in a metal panel or wall there is a risk

of permanent damage due to a jagged opening or too small
of an opening. The metal panel can short circuit the display
rendering it inoperable and requiring the installer to replace
it. Ensure that the edges of the cutout are smooth and that
no material is bent outward where it can dig into the display.
Make sure that the cutout is large enough so that the display
can be easily inserted without having to angle it. There is a ½”
border all around the display to cover the edge of the hole, so
if the hole is a bit larger than the minimum requirement it will
still be covered by the display.
2. When fastening the display to the panel, make sure that it is
centered in the hole and not resting on one edge.
3. Non-conductive mounting spacers are available to help
prevent damaging the display. Contact Garnet for further
details.

How to avoid damaging the display or pump switch due to

excessive current:

1. Please be aware that the water pump switch circuit has a

limitation on current draw of 10 amps, some large pumps
can draw over 10 amps. These high drain pumps must use a
relay or the display console printed circuit will overheat and
damage the display permanently.
2. If the 12V supply line from the electrical panel does not have
a 10 amp fuse rating, please be sure to install the supplied
fuse holder with a 10 amp automotive style fuse inline on the
+12V red wire.
3. WARNING: All power circuits must be fused. If a fuse
is not provided with the system then it is the installer’s
responsibility to install a fuse with a maximum rating
of 10 amps. A relay is required if more than 10 amps is
needed for the pump.

709-DLP Manual Page 31

 CHAPTER 8 - SPECIFICATIONS

Resolution JS sender: ¼" (6 mm)

ES sender: ⅜" (10 mm)
SS sender: ½" (13 mm)
Accuracy: +/- 8% or better, limited by resolution and tank height
and shape.
Temperature range: +32 to +140 °F (0 to + 60 °C)
Sender materials: 0.008" thick glass epoxy circuit board with conformal
coating for circuit protection. Laminated on the back
with 3M 300LSE Bonding Adhesive.
Sender length range: JS sender: 4" to 6", which will measure tank heights
from 4½” to 7”.
ES sender: 4 ½" to 12", which will measure tank
heights from 5” to 13” (single sender) and up to 25”
(dual senders).
SS sender: 6" to 16", which will measure tank heights
from 7” to 17” (single sender) and up to 34” (dual
senders).

Display mounting panel: Black panel, approximately 4" wide by 2.8" high by 1"
thick (102mm wide X 71mm high X 25mm thick).
Panel screws to wall.
System power requirements: Display requires 12 volts from the RV battery, the
system will function from 11 volts to 16 volts. Current
drain is less than 200mA.

Wiring: A single two wire conductor required from the display

to the senders. All the senders are wired in parallel.
12 V power and ground required for display. A
separate two wire conductor required from the display
to each LPG sender.

LPG: Display will work with an LPG sender with a maximum

resistance of 50 ohms to 500 ohms. Display shows
increasing level as resistance increases. System
must be calibrated with the LPG tank full.

Pump switch: The pump switch is rated for a maximum of 10 amps.

The use of a relay is required if more than 10 amps is
needed. A 10 amp (max) fuse must be installed in
series with the 12V power circuit to the switch!

Page 32 709-DLP Manual

 CHAPTER 9 - SERVICE AND WARRANTY INFORMATION

T he warranty will apply only if the warranty card shipped with the equipment has been
returned to Garnet Instruments Ltd.

DISCLAIMER OF WARRANTY ON HARDWARE

Garnet Instruments Ltd. warrants equipment manufactured by Garnet to be free from defects
in material and workmanship under normal use and service for a period of one year from the
date of sale from Garnet or an Authorized Dealer. The warranty period will start from the date
of purchase or installation as indicated on the warranty card. Under these warranties, Garnet
shall be responsible only for actual loss or damage suffered and then only to the extent of
Garnet’s invoiced price of the product. Garnet shall not be liable in any case for labor charges
for indirect, special, or consequential damages. Garnet shall not be liable in any case for
the removal and/or reinstallation of defective Garnet equipment. These warranties shall not
apply to any defects or other damages to any Garnet equipment that has been altered or
tampered with by anyone other than Garnet factory representatives. In all cases, Garnet will
warrant only Garnet products which are being used for applications acceptable to Garnet and
within the technical specifications of the particular product. In addition, Garnet will warrant
only those products which have been installed and maintained according to Garnet factory
specifications.

LIMITATION ON WARRANTIES
These warranties are the only warranties, expressed or implied, upon which products are
sold by Garnet and Garnet makes no warranty of merchantability or fitness for any particular
purpose in respect to the products sold. Garnet products or parts thereof assumed to be
defective by the purchaser within the stipulated warranty period should be returned to the
seller, local distributor, or directly to Garnet for evaluation and service. Whenever direct
factory evaluation, service or replacement is necessary, the customer must first, by either
letter or phone, obtain a Returned Material Authorization (RMA) from Garnet Instruments
directly. No material may be returned to Garnet without an RMA number assigned to it or
without proper factory authorization. Any returns must be returned freight prepaid to: Garnet
Instruments Ltd, 286 Kaska Road, Sherwood Park, Alberta, T8A 4G7. Returned warranted
items will be repaired or replaced at the discretion of Garnet Instruments. Any Garnet items
under the Garnet Warranty Policy that are deemed irreparable by Garnet Instruments will be
replaced at no charge or a credit will be issued for that item subject to the customer’s request.

If you do have a warranty claim or if the equipment needs to be serviced, contact the
installation dealer. If you do need to contact Garnet, we can be reached as follows:

CANADA UNITED STATES

Garnet Instruments Ltd. Garnet Technologies Inc.
286 Kaska Road 201 M&M Ranch Road
Sherwood Park, AB T8A 4G7 Granbury, TX 76049
CANADA USA
email: info@garnetinstruments.com email: info@garnettechnologiesinc.com

709-DLP Manual Page 33

Page 34 709-DLP Manual
 TO MAXIMIZE YOUR WARRANTY PLEASE REGISTER ONLINE AT www.garnetinstruments.com OR MAIL THIS FORM IN TO GARNET.

LIMITED WARRANTY REGISTRATION

MODEL NO. SERIAL NO. SENDER BAR SERIAL NO. (if applicable)
MAIL IN WARRANTY

IMPORTANT: WITHOUT THE SERIAL NUMBER OF EACH UNIT IT IS

DATE PURCHASED DATE INSTALLED DIFFICULT TO DETERMINE WARRANTY VALIDITY
YR/MO/DAY YR/MO/DAY

COMPANY NAME DEALERS NAME

PRINCIPAL CONTACT WARRANTY CONTACT

ADDRESS ADDRESS

TELEPHONE FAX TELEPHONE FAX

IN CANADA RETURN TO: IN UNITED STATES RETURN TO:

Garnet Instruments Ltd. Garnet Technologies Inc.
286 Kaska Road 201 M&M Ranch Road
Sherwood Park, AB T8A 4G7 Granbury, TX 76049
CANADA USA

IMPORTANT: RETURNING THIS CARD WILL ENABLE US TO NOTIFY YOU IN THE EVENT OF A PRODUCT RECALL OR TO SUPPLY YOU WITH REQUIRED PRODUCT SAFETY INFORMATION.
NOTES: