Preheat error

Updated 3 months ago ​by Tomáš Chvalina

The preheat error can occur with either with your Nozzle or Heated bed. So 1st make sure with which of these you have the problem.

Would just the Preheat error display on the LCD screen. Then it refers to the Hotend. If the error would be Heatbed preheat error. Then the problem lays within the heated bed. 

Preheat error (Hotend)

Things to check:

  1. Check out that your Hotend thermistor/heater leads are properly seated in the Hotend.
  2. Open the miniRAMBO or EINSY RAMBo box and check that your heater connector/thermistor is properly plugged in. 
  3. If you've checked all the above and everything is in order. Please re-flash with the latest firmware found at www.prusa3d.com/drivers. A quick guide on how to flash new firmware can be found at Firmware upgrade and flashing.
  4. Would the issue still persist then there is something wrong with your Heater or Thermistor. In order to find out which one of these is malfunctioning. Do the simply test described bellow.

Heatbed preheat error (Heatbed)

Things to check:

  1. Make sure that your Heated bed thermistor is properly seated under the Golden kapton tape (photo below).
  2. Remove the cable cover from the back of the heated bed and inspect the leads to ensure they are still intact and soldered securely to the pads.
  3. Make sure the Heatbed connector is fully seated into the socket on the miniRambo or screwed in tight into the socket on the EINSY RAMBo - !You should routinely check this in general!
  4. If you've checked all the above and everything is in order. Please re-flash with the latest firmware found at www.prusa3d.com/drivers. A quick guide on how to flash new firmware can be found at Firmware upgrade and flashing.
  5. Would the issue still persist then there is something wrong with your Heater or Thermistor. In order to find out which one of these is malfunctioning. Do the simply test described below.

How to find out if your Heater or Thermistor is defective for your Nozzle/ Heatbed? 

It is not very common, but there is a chance that extensive printing damaged your heater or thermistor. 

The most effective and the easiest solution is to take a hair dryer and blow hot air at the Hotend or Heatbed. During this process just check if there is any temperature change on the LCD. If there is a change, it means that your thermistor is working, which means that the heater is damaged. If there is no change at all, your thermistor is defective.

Do not hesitate to contact us at info@prusa3d.com if you would have any following questions.


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