!
error Miller

Error Code Thermistor RT1 or RT2 open (overheating)

Thermistor RT1 or RT2 has opened, stopping output. The cooling fan will run until the unit cools and temperatures return to acceptable limits.

? What Causes This

Unit exceeded duty cycle rating or internal temperature became too high due to continuous operation or blocked ventilation.

How to Fix It

  1. Allow the cooling fan to run and wait for the unit to cool.
  2. The unit will be automatically enabled when temperatures are within acceptable limits.
  3. Reduce amperage, voltage, or duty cycle before welding again.

Source: page 32 of the official manual

From the manual

Manual page 32 — Miller error Thermistor RT1 or RT2 open (overheating)

This error code appears in:

Miller 350P Welder