Schaudt control panel IT 992 defective

[terricola]

Hi all,
I have a Hymer b544 with a malfunctioning Schaudt control panel IT 992. It does not indicate correctly the fresh water tank level.
I cleaned the sensors but the indication remains bad, with full tank the indication is 1/2. So probably the sensors circuit lose sensitivity.
I wrote to Schaud but they do not want to send me the electric diagram of the IT 992 control panel.
Does anybody know where can I get the electrical schematic diagram?
Thanks in advance.

Ernest

 

[jezport]

Check the contacts in the connecting plug to the tank sensors

 

[terricola]

Thanks!!
I did it and also cleaned with contact cleaner and they are OK.
Schaudt recommend me to short circuit the sensor bars directly and doing this, the indication of the panel is correct. Short circuiting the "base" with the "full" sensor, the panel indicates full, and same with 1/4, 1/2, 3/4.
Due to this I guess the problem is that the detection circuitry lose sensitivity, because the resistance between the sensors inside the tank is about 10MOhm (not 0 as a short circuit).
So I am searching the electrical diagram, to try to repare or re-adjust the circuit, but Schaudt does not support me and by the moment I can not find the diagram...

 

[tonyidle]

Thanks!!
I did it and also cleaned with contact cleaner and they are OK.
Schaudt recommend me to short circuit the sensor bars directly and doing this, the indication of the panel is correct. Short circuiting the "base" with the "full" sensor, the panel indicates full, and same with 1/4, 1/2, 3/4.
Due to this I guess the problem is that the detection circuitry lose sensitivity, because the resistance between the sensors inside the tank is about 10MOhm (not 0 as a short circuit).
So I am searching the electrical diagram, to try to repare or re-adjust the circuit, but Schaudt does not support me and by the moment I can not find the diagram...

The sensors are stainless rods. When shorted the indication at the plug should be near-enough zero ohms. If it isn't the fault is with the sensor assembly. Each rod is connected at the top to its own individual wire. The connection is made using a copper connector soldered to the wire then pushed onto the rod. The connections are then embedded in epoxy. Last time I had the fault you describe water had sneaked up the rod past the epoxy and badly corroded the copper connector. The cure is replacement or, as I did, clear out the epoxy and re-make the connections. I gave the top of each rod a blob of braze (brass) and soldered each wire to its rod. I used Sikaflex to bed them rather than epoxy.

 

[terricola]

Very interesting... thanks for the idea.
I made the following sets of measurements:
1- resistance between each stainless rod (previously very well cleaned and bright) and its connector terminal, and all of them showed 0,0 - 0,1 Ohm, except the yellow (this is 1/2 level rod) that showed 4.8 Ohms.
2- out of water "insulation" between each individual rod among all other 4 ones and they measured 10-12 MOhm.
3- in the water resistance between each individual rod to the "base" one and the values were from 1MOhm to 3.2MOhms.
If I can not get the schematic diagram of the control panel to measure the circuitry, then I will check your suggestion or maybe first explore the data of the wasted water to see if they are comparable. In this case the problem will be to make a connector adaptor because clean water sensors has a 6 terminals connector and the wasted water has a 5 terminal connector. Not so difficult.
Thank you very much for your suggestions

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[DJ Pieters]

Hi all,
I have a Hymer b544 with a malfunctioning Schaudt control panel IT 992. It does not indicate correctly the fresh water tank level.
I cleaned the sensors but the indication remains bad, with full tank the indication is 1/2. So probably the sensors circuit lose sensitivity.
I wrote to Schaud but they do not want to send me the electric diagram of the IT 992 control panel.
Does anybody know where can I get the electrical schematic diagram?
Thanks in advance.

Ernest

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