Know the Keld 2
Turn the machine, pick a marker, and try the parts that move. The two gauges in the middle are the first thing you check every morning.
Read both gauges before you touch anything else on the machine.
It is 7:05. The Keld 2 was switched on at 6:45 and the status light is still pulsing amber. The boiler needle sits below its green band and the first customers are at the door. What do you do?
Start pulling shots. The pump gauge is what matters for espresso.
Wait. If the needle is still below its band once the warm-up time in your manual has passed, call the technician.
Take the side panel off to check the boiler.
A slow amber pulse means the machine is still heating, and the boiler needle below its band says the same thing. Give it the warm-up time your machine's manual gives. If the needle is still below the band after that, call the technician: the boiler is inside the panels, and the panels are not an operator's job.