Don`t you just hate it when....

....you`re telling the customer why his equipment keeps playing up i.e a refrigerated compressed air dryer thats in a draughty position is tripping on high compressor temp caused by cold air constantly passing over the condensor pulling the evaporator pressure down. This causes the hot gas valve to shunt hot gas into the evaporator outlet to keep the pressure up but then allows inlet temp to compressor to keep rising until it trips. While you`re telling him this he gives you a sideways glance as if to say "what a load of bollox"
Now, I have been known to talk with a certain testicular bent in my time but when you`re being genuine...don`t you just hate it?

It's the old problem isn't it?

They will never, ever, go wrong while you are within 20 miles of it.

I have found the "Sheet of Cardboard"
trick.
Can help prove ones point!
It might not chill the miserable customer, but it will help you prove your point.
Grizzly

Nice post by the way!

As Grizzly says; try a piece of cardboard to prove your point.;)