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Topic: SeeLevel replacement sensor strip--what length to order for RB grey tank? (Read 349 times) previous topic - next topic
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SeeLevel replacement sensor strip--what length to order for RB grey tank?
I had a repair shop replace my entire seelevel system.  fresh and black are reading fine, but grey is way off.  It says 100% when it is only half full.  I understand sensors cannot be moved, but must be replaced to correct the problem.  I assume the installed sensor is the default 12" that comes in the kit.

Now that I am replacing it, what is the proper length to order for a 2004 RB grey tank?

Thanks.
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #1 –
I suggest you call the manufacturer and ask them. Be ready to tell them the dimensions of the tank upon which you wish to mount the new sensor. Measure top to bottom, and they will tell you what you need. Alternately you can mount the strip mid-way of the tank, top to bottom, and interpret the readings accordingly.   ;)
Steve S.
Lazy Bones & Cedar
2004 30'IB (Island Bed)
Yesterday is History, Tomorrow is a Mystery
Live for the day!
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #2 –
Can you get the shop that did the work to fix the problem?

Jim
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #3 –
If you have warranty coverage on the work done, don't worry about it.  Take it back and have them fix their work.

Assuming that you will be dealing with this yourself, the sensors measure water levels by sensing through the tank wall.  If you only partially cover the tank wall with the sensor, once the level drops to the bottom of the sensor, it will read empty, and conversely, once you reach the top of the sensor, it reads full. 

You have a few options here.  You can pick a sensor that ALMOST covers the flat wall of the tank.  That's what I did.  My recollection is that I used the single, full length sensor, and may have trimmed a bit.  When my tank level drops below the bottom of the sensor, it reads empty, and when my tank reads 100%, I can get two to three more days of use in it.  The sensors' lengths are adjustable by trimming them. 

The SeeLevel II Model 709 manual states, "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..."  To size the sensor, they say, "For tanks less than 7 inches tall, 50% better accuracy is achieved by using the JS sender, which can be shortened for a minimum of 4 inches. For tanks from 7 inches to 13 inches tall, a single ES sender is used. For tanks from 13 inches to 25 inches tall, two ES senders can be stacked to allow measurement of levels up to 24 inches." 

So, measure the wall height of your grey tank near the outlet.  (The tank is tapered and the upstream end is not as high as the outlet end.  Put the sensor at the outlet end.)  Clean off the tank surface where you want to mount the sensor, per instructions, adjust the sensor length as needed, and tape it in place.  Connect the black and blue wires  to your existing wires with waterproof splices, being careful not to tug on the wires where they attach to the sensor.  Test the system to be sure the sensor works.  Peel off the sensor backing and attach it to the tank.  Use a wire tie or two to secure the wiring so bumps, wind, etc. will not cause pulling on the sensor when traveling.  They recommend spraying a good undercoating on the sensor to protect it.

Below are the complete instructions for mounting the sensors.  Note particularly Step 12!

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 inch away
from 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 how long the
senders should be. For tanks less than 13” tall, follow step 6.
For tanks greater than 13” tall, follow step 7.
7. For tanks less than 13” tall, a single sender is used. For tanks
less than 7” tall a 710JS sender should be 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. The ES sender is cut to the nearest even 1.5 inch
in length, for example, a system with a tank height of 11.75
inches, cut the sender to be 10.5 inches 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 inch in length.
IMPORTANT: Do not cut the 710ES sender shorter than 4-1/2
inches! The sender will not work if it is cut less than 4-1/2
inches. Do not cut the 710JS sender shorter than 4 inches!
The sender will not work if it is cut less than 4 inches.
8. For tanks greater than 13” tall, two stacked 710ES 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” to between the two senders. Therefore total
length of both senders will be: tank height -1/4”-1/4”-1/8”,
then rounded down to the nearest 1.5 inches. 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 senders
will be 21 inches. Make both senders 10.5” long.
9. 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). DO
NOT cut the sides, and DO NOT cut the 710ES sender shorter
than 4-1/2 inches or the 710JS sender shorter than 4 inches.
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.
10. 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” and the section “To program the 710ES or
710JS sender for the correct tank” for details.
11. For two stacked sender systems, the senders need to be
programmed so they know that they are being used as
top or bottom senders. See the chapter entitled “SENDER
PROGRAMMING” and the section “To program the 710ES
sender as top or bottom” for details.
12. 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, and
more 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.
13. Do steps 4 to 12 for the other two holding tanks.
14. 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.
15. Connect the green wire from the display to the LPG tank
sender. Make sure that the sender ground connection is
connected back to the display ground or the breaker panel
ground.
16. 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 one or two sender system for each tank. See the
chapter entitled “DISPLAY CALIBRATION” and the section
“To calibrate the number of senders for each tank” for
details. Make sure you do it for each tank.
17. 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-
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.

Ken F in NM
'08 MB
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #4 –
Ken, when do you expect the technical consulting fee from See Level? 😉

Great job!
2003 TK has a new home
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #5 –
Wow.  Thanks Ken.  I assume you have a rear bath and that the shape and location of the tank have not changed much over the years.  Mine is a 2004.  May I ask your model year?

My LD is not stored near my house.  So, right now, I am trying to complete step one by ordering the correct length sender.  I thought that rear bath owners might be able to tell me the length of their grey tank senders.

Thank you for taking so much time to provide such an impressive response.  I'm very grateful for your guidance.  I will follow it carefully at installation time.
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #6 –
Ted, I have a MB '08.  Thus, your grey tank might be different than mine, but the standard sensor is likely to fit.  Get confirmation if you can from someone with a RB.  The measurement you want is the FLAT part of the wall of the tank.  You might have curved parts at the top and bottom.  You can't place the sensor on a curved surface.

Ken F in NM
'08 MB
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #7 –
I have never found an LD that a 12" sensor strip doesn't work.
On many holding tanks, the sensor needs to be trimmed. This may result in a readout that isn't exactly 0-100%
Read the Factory instructions on how to shorten the sensor, it's needs to be precisely done.

Each tank has a optimum sensor position, I initially install each sensor strip with masking tape, and then adjust the sensors to determine where the holding tanks are exactly 100% full and the freshwater tank is 0% empty, the three measurements I'm most interested in.

Since the sensor cannot be the exact right length, most of the time you end up with 'full' or 'empty' reading that isn't 0% or 100%.
Our LD's fresh water tank is set to show 0% when it is empty, when it is full the SeeLevel shows only 92%
The gray and black tanks show 100% when full and show 8% when empty.
There is no way to avoid this but it isn't an issue once you know and record the percentage range of each tank's sensor.

After the sensors have been used a while and shown to be in the right positions, permanently mount the sensors, peeling off the paper protective strip, exposing the sensor's adhesive back.

We install a SeeLevel system in our LD eleven years ago, it has worked fine ever since.
Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #8 –
Thanks, Larry.  Your strategy is exactly the one I have pursued.  I don't care what fresh reads when it is full, only when it is empty and the opposite for the waste tanks.

I suspect the reason yours has lasted for 11 years  and  my first one lasted 7 years (the readings) is that I am at the mercy of repair shops.  For this grey water sensor replacement, I have the help of a generous friend.

One question.  Do I understand correctly that you actually drive the coach and use it, while the sensors are attached temporarily, until you are sure of accuracy through multiple cycles before attaching them permanently? If so, I take it  you have taped them firmly so they have continuous contact with the tank and stay in place during this exercise.
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #9 –
"Do I understand correctly that you actually drive the coach and use it, while the sensors are attached temporarily,..."

You have to understand that Larry is the pentultimate fidget! It would not surprise me if he does just that... until he is dead satisfied that everything is where he wants it.

I on the other hand would think that positioning the sensor, temporarily, once, twice, even three times until you are satisfied with the reading. Of course having prior knowledge of the level of liquid in the tank being worked on would be most helpful.

Larry's explanation of adjusting for percentages is spot on!   :D
Steve S.
Lazy Bones & Cedar
2004 30'IB (Island Bed)
Yesterday is History, Tomorrow is a Mystery
Live for the day!
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #10 –
Steve--Not surprised...just confirming!
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #11 –
Larry's recommendation to tape and test is in line with the SeeLevel instructions Step #12.  Yes, you need to use enough tape to be sure the sensor is in continuous contact against the tank.  If you want to minimize the time with it taped, fill the grey tank, temporarily position and tape the sensor, test the system, dump the tank, test the system again, and if all is ok, go ahead with the permanent mount.

Ken F in NM
'08 MB
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #12 –
Quote from: Kenneth Fears  - 
Larry's recommendation to tape and test is in line with the SeeLevel instructions Step #12.  Yes, you need to use enough tape to be sure the sensor is in continuous contact against the tank.  If you want to minimize the time with it taped, fill the grey tank, temporarily position and tape the sensor, test the system, dump the tank, test the system again, and if all is ok, go ahead with the permanent mount.

Ken F in NM

Thanks, Ken.  I ordered the sensor and will follow Larry's and your advice.
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #13 –
Thanks to everyone for the great help with my query.  I have ordered a standard, 12" sensor.  Also appreciate the bonus of detailed installation instructions and tips.  Best wishes to all.
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #14 –
Quote from: LD-TED  - 
One question.  Do I understand correctly that you actually drive the coach and use it, while the sensors are attached temporarily, until you are sure of accuracy through multiple cycles before attaching them permanently? If so, I take it  you have taped them firmly so they have continuous contact with the tank and stay in place during this exercise.

Yup, 3M blue masking tape work just fine for attaching the sensors, for the short term.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: SeeLevel replacement sensor strip--what length to order for RB grey tank?
Reply #15 –
Ted, if you do not have a SeeLevel installation manual, message me with your email addy and I will send one.  You need to cut a part to set the sensor to length as well as to identify it as for the grey tank.

Ken F in NM
'08 MB