German Reprap X400-Low nozzle temperature

We have a new X400 that was purchased assembled by German Reprap. We haven't been able to print any parts for couple of months. German Reprap has not been able to diagnose any of the problems. We have determined that the repetier host extruder head temperatures read-out displays temperatures approximately 60 degrees C too high. Example: We set 280 Degrees C, the software shows actual: 250 Degrees C. However when we measure the nozzle temperature with calibrated electronic and infrared thermometers the actual temperature at the nozzle is 175 Degrees C. (The nozzles are covered with insulation). We measured the thermistors to be 101K Ohms. The RAMPS getting 12.1 VDC from the power supply. We don't know what to do next. Please HELP. Thank you in advance.

... you have to recalibrate the thermistor-settings in the firmware to get correct measurings ...

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Viktor
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Hello Victor,
We greatly appreciate your help.
Would it be possible to send us instructions on how to calibrate the thermistor settings.
Best regards,
Savvas

How did you upload your firmware? Did it come preinstalled or did you use the Arduino IDE or other means?

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

We used Arduino IDE
Thanks,

Sorry, should have asked in the same post; what firmware are you using?
When you open up your firmware in your IDE switch over to the configuration.h tab and scroll down/search and find the thermistor portion. Change your number to match your thermistor type. It should give you a list with numbers matching it's type [ie. "// 1 is 100k thermistor" would be set by "#define EXT0_TEMPSENSOR_TYPE 1"

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

The firmware that we are using is Arduino 1.0.5-r2. The number already matches the thermistor that we have which is Type 1.

We did some testing of both extruders.
On Nozzle 1 we had...
Computer Set Value Computer Read Value Actual Infrared Value
300 259 180 (With Kapton insulation)

The Computer Read Value never goes above 259 degrees Celcius.

On Nozzle 2 we had...
Computer Set Value Computer Read Value Actual Infrared Value
205 205 90
205 205 103 (With Kapton insulation)
300 260 131 (With Kapton insulation)

We have tried to contact German RepRap support with questions, but they don't give us any useful information. We don't know why the actual temperatures can't reach what we need. We are very disappointed with this machine. We have been trying to print material for the last 4 months with absolutely no help from them.

Thank you for any help you can give.

I do not think you could use any infrared reading as this is not destined for any small point of reading but needs some area to give you a fair reading.
You would probably need a Pt100 based reading with a tiny (mass) of point to contact your printerhead. even that is not accurate as your thermistor is probably placed very close to heater or better inside the heater. The difference between temperature measured inside and outside heater can be distinctive.
Only a calibration in a heatchamber can verify your actual values.
From your readings above it looks to me that your infrared readings are far from reliable and should not be used for any calibration.
It also looks like you have a max setting in FW of probably 260C which does not allow heater to go higher than that.
Calibration is at least two things:
1 ) You need to be convinced that the thermistor used is the one you have selected in FW. You may try to place your heater secured for water into boiling water or similar to verify at least one spot.
2) you also have to calibrate your PID settings by using auto calibration command M303 see this : [reprap.org]