Bobcat A770 12-21 Error Code
12-21 Error Code
Auxiliary Pwm Switch Out Of Range High is the main cause of 12-21 error.To solve 12-21 locate and open the low-pressure valve, then attach the refrigerant to the valve and charge from there. Ensure you use the right refrigerant type and amount, as specified by a manufacturer. It is possible to overcharge the AC, so consider seeking help from a mechanic.
Tip For A770 Model
The overload warning device (if equipped) senses
hydraulic pressure in the boom lift circuit. When the
hydraulic pressure in the boom lift circuit reaches a
predetermined pressure setting, a buzzer will sound that
indicates an overload condition.
If the buzzer sounds, immediately move the arm closer to
the excavator and lower the boom. Reduce the size of the
load before attempting to re-lift the load.