You may have found yourself with a Fujitsu system that when you replace the boards, they go bad again. This shouldn't happen and is not normal. Take the steps below.

Typically the boards go bad due to an external electrical issue or a bad component, namely the EEV, Fan Motor, or the compressor. In rare cases it could be a thermistor that is shorting to ground.

Steps to take:

1. Verify incoming voltage- Most mini splits have an acceptable voltage range of 187-253 Volts AC. IF you are outside of these parameters or really close, consider a Rectorseal 96421 or 96424 line voltage monitor and surge protector.
2. Verify internal components- Compressor, EEV, Fan Motor.
3. Depending on the system you are working with, you may want to replace the active filter module as well. If the system is under warranty, replace them all
4. When replacing boards, be sure to use the supplied thermal sheets and or paste. Also make sure all screws make it back in to the board.

If you need more step by step help, use the troubleshooting part of our tech support bot.