For those who won’t admit to being mesmerized by these amazingly simple toys, it’s basically a plastic box with numerous buttons, knobs, slides, and other fun things for children to play with. These wonderful devices can keep babies happily occupied for ages (or even a half-hour).
Now there seems to be a high-tech busy box for service technicians — the thermostatic expansion valve (TXV). Being one of the only parts of the system that can be easily adjusted, that knob on the TXV poses a temptation that many technicians just can’t resist.