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Help needed AF-2500 EMS

Janekom

Well Known Member
Patron
I am trying to help someone with and AF-2500 EMS in his RV10. The Oil Temperature does not seem to work properly.

It is a 2007 vintage and has worked for years until the owner had problems and changed the sensor.

With reference to the manual:
On the top right a number will appear. This is the digital value read by
the sensor you are calibrating. This value will change if the condition the
sensor is reading changes.
Below this number there will be a list of calibration data. Use [NEXT]
and [PREV] buttons to scroll through the calibration list.
To adjust any of the warning values make sure the cursor is on the
desired one and twist the knob until the value you desire is displayed.
When you have calibrated the instrument you can return to the main
instrument list by pressing the [RETURN] button.


Just as in the manual, we see the 2047 on the top right of the screen, with the sensor connected. Is this really the digital reading from the sensor, or something else?

With the sensor disconnected we saw a reading of 7.

We have bench tested the sensor with a multimeter on Ohms. We get around 4K in cold water and around 20K in boiling hot water. It might have been the other way round - sorry. I assume it is a resistive sensor? The part number is GRT FT-LC-01.

BUT connected to the system and in Configuration mode, the top right reading sits at 2047 no matter where it is - hot or cold water.

When in normal mode the temperature readings seems to be either stuck or reads too high.

What are we doing wrong if anything?

Can someone please assist with recommendations please?
 

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Case closed thank you

No one responded here but Support gave me the answer - see below.

Jan the GRT sensor will not work with that unit. The original sensor is not a common resistive based sensor such as the GRT, it is an IC based sensor that outputs a current based signal of 1 μA/K absolute temperature. We have replacements available for USD $70 + shipping to South Africa. Note that OAT probe for this product is the exact same sensor just potted in a different housing. So before purchasing a probe it would be worthwhile to move the OAT wires over to the oil temp wires as a test just to be certain it was the old probe that went bad, and not something in the Analog Module.

So we have the wrong sensor - I have no idea where and when the wrong sensor has been installed.
 
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