Or he has a restriction. In fact, if his dryer is original, it is likely the first design which did tend to plug. There's a TSB on this.

Blindly filling the system is not a good idea because of the possibility of a restriction. The pressure transducer is at the dryer outlet, so the high-side pressure can spike but the climate-control unit won't know it.

Mine read 350 psi at the high-side service port, while the climate-control unit reported 3 bars.