Headhunter Tank Monitor Calibration

[phorner]

I was experiencing a minor problem with my waste tank Headhunter tank monitor. When the waste tank was empty, I would still get an indication of 10% full, which eventually became a 20% full indication over several months.

On my Liberty conversion, there is a single waste holding tank as opposed to separate gray and black water holding tanks. The end of the air line that extends into the waste tank can become partially clogged which can lead to inaccurate "empty" readings.

You can simulate an "empty tank" condition by removing the red plastic clip and disconnecting the air hose from the sending unit. I removed mine from the sending unit and applied a little compressed air to the line, forcing air into the tank to clear the line out. This worked very well.

The manufacturer also recommended that I re-calibrate the "empty" setting. This is performed with the power on and the tank empty (or disconnect the tubing from the SYM sending unit). The light on the sending unit should be flashing green.

On the back of the LED remote readout, there are 2 trimpots: the green one adjusts the zero (empty tank)readout. When all the LEDs are out, adjust the green trimpot counterclockwise to the point where the 10% light comes on.

Then, adjust the green trimpot clockwise until the 10% light goes out.

Finally, continue turning an additional 1/2 turn clockwise.

If you have disconnected the tubing, reconnect and push the purge button on the SYM sending unit.

Following these procedures resolved my tank level display issue.

[Jon Wehrenberg]

To simulate a full tank I use a very tall container that I have that is nearly the same depth as the tank to simulate the full tank level for calibration purposes. It is faster and easier to add a couple of gallons to the container than to add 100 plus gallons to the real tank.

I find I have to calibrate the holding tank sensors more frequently than I really care to so I find if I never fill my fresh water tank unless the holding tank is empty, and then never use municipal water I really do not have to worry about how it is calibrated. I do not use the auto fill feature for that reason.

[GSwaim]

I have this same Headhunter tank monitoring system on my Royale and it appears it is due to a poor design. From what I've been able to glean from headhunter monitoring system users so far, the system has a 100% failure rate history. The sending units appear to be the worst culprits for failures but the other components are just as likely to fail. Can fellow Headhunter tank monitoring owners confirm or dispel this?

On my 02 Royal XLII all three of my sending units have failed and now it appears the main control has failed as well. This system failing wouldn't be so bad if it weren't for two things:
1. This system triggers my freshwater autofill system so without it I have to keep watch on how full the FW tanks is myself.
2. The headhunter system components are extremely overpriced to replace to expect another failure in the near future.

Since this system plays a fairly significant role in the convenience of my water system autofill and waste tank monitoring, I've decided to create a better mouse trap. I'm working with the engineers over at Phoenix Royale to build an alternative monitoring system that will use the same tank sensor tubes that headhunter did but be far more dependable and fairly inexpensive to covert from headhunter sending units and displays to a more accurate and robust set of monitoring components. The prototype will be installed this month and I will begin testing the new system to ensure the system's worthiness.

Is anyone else having problem with their tank monitoring system?

[Jon Wehrenberg]

I have found the opposite. I think the Headhunter system on my coach tends to be quite reliable, but I'm not impressed with the tubing arrangement that goes into the tank. If there are leaks at the tubing connections, due to the low air pressure used for sensing the readout will be incorrect.

Before I went ahead and spent serious money reinventing the wheel I would check the integrity of the tubing connections. It will be a very cheap fix that might correct problems.

[michaeldterry]

-snip-
Is anyone else having problem with their tank monitoring system?

Since the day I got my coach, the tank monitoring has not worked properly. The monitor panel shows 100% full for all three tanks all the time regardless of the actual level/condition. I want to remedy this at some point and have a working tank monitor system, but it just hasn't risen high enough on the priority list yet! :o

[GSwaim]

Jon,
Thanks for the tip. I spent a few days learning the Headhunter monitoring system and then troubleshot my system completely. My efforts revealed that the sending units were not working any longer. When I called for replacements I was told "Oh ya, these sending units have a 100% failure rate, how many would you like?" At $600 a pop, I decided NONE.

I'm a fixer so I opened up the sending units to take a look at what was wrong to find a tinker toy appearance to their engineering. I finally decided it would be better to start over then to try and fix the cheap crap they used in these sending units then smothered the contents in epoxy to hold them together.

[GSwaim]

The new headhunter Tank Monitoring System is built, installed and working terrific! Instead of the three headhunter pump sensor boxes, I now have one six inch box with all three pumps and all three sensors. The main control board has the ability to do a fourth sensor if someone needed it as well as send the tank status to multiple display panels. I decided on two display panels, one in the bus and one right at the flush and fill valves. The system has been in for several days now and is very accurate and very dependable. Take a look and tell me what you think.

http://swaimquest.com/images/Sensor%20box.JPG

Control, Sensors & Pump box located in overhead of tank bay. This box can replace a set of bad Headhunter sensor pump boxes and still use the Headhunter display for a fraction of the cost it would take to replace the headhunter junk. Even better, all the internal components of this system are individially replaceable if anything should fail unlike the Headhunter boxes which are dipped in epoxy to prevent any repairs.

http://swaimquest.com/images/Main%20sensor%20panel.JPG

Inside display, made up of small 2" displays and autofill system switch.

http://swaimquest.com/images/Bay%20tank%20panel.JPG
Small display for utility bay. Going to add a autofill switch at this location in the near future.

I currently have the sensor tubes being purged every five minutes for only 3 seconds and the gauges are super accurate so far. This purging process is silent so no more annoying wine like the HeadHunter junk. The auto fill is set to fill at 20% empty and stop filling at 95% full. This works perfectly but could be changed easily for personal preference. The next step is to add a pressure sensor to the fill side of the autofill valve so it will not stay engergized if city water service isn't connected. Let me hear from you all on what you think of the new system and if there is any interest here.

[JIM CHALOUPKA]

That's all very nice, but until my existing monitor craps out I can't get too excited.

JIM:)

[Jon Wehrenberg]

Was the use of the word "craps" intentional?

[JIM CHALOUPKA]

Was the use of the word "craps" intentional?

You bet!:D

JIM :cool:

[GSwaim]

Jim,

Is your HeadHunter tank monitoring system working or has the sensor boxes gone bad? Just wondering since since my new all-in-one sensor box will work with your current headhunter display and wiring. May be a good way to fix your tnak monitoring system without spending the high price for headhunter sensor boxes ($600 each).