This error refers to a problem with the sensor of the heated bed. It means that the sensor registers incorrect values and due to safety reasons it will prevent the heated bed from heating up. If you get a "MINTEMP error BED" the Ultimaker Original+ registers a too low temperature, while a "MAXTEMP error BED" suggests a too high temperature. The most likely reason for this is connection problem, which could happen due to a bad connection on the heated bed or main board, or damage of the sensor itself.
Make sure to always turn the Ultimaker off and disconnect the power supply before troubleshooting this error.
The connections at the heated bed can easily be verified by checking if the sensor wires are well secured. These are the two thin wires connected to the screw terminal at the back of the heated bed. Gently pull them to see if none of the wires is loose. If one of them is loose you will have to remove the heated bed so you can reconnect the wires.
To check if there is a bad connection on the main board you will have to take a look at the bottom of the Ultimaker:
- Place the Ultimaker Original+ on its side so you can reach the bottom side and remove the wooden electronics cover.
- Now you will see the main board. Look for the sensor cable of the heated bed, which is connected to 'TEMP3'. Ensure it's properly connected.
As an extra test you could try swapping the heated bed sensor (TEMP3) with the PT100 sensor (TEMP1). Try heating both and check if you still get the same error:
- When the heated bed sensor is connected to 'TEMP1', try heating the nozzle. Are you now getting the "MINTEMP or MAXTEMP Error"? The problem has moved along with the sensor, so the heated bed or heated bed cable must be faulty.
- When the PT100 sensor is connected to 'TEMP3', try heating the heated bed. Are you now getting the "MINTEMP or MAXTEMP Error BED"? The problem is still on the same place, so is probably caused by the main board.
For further assistance you can get in touch with one of our local support partners.