Quick control panel wiring question

It's a 4-wire 220V input. Line 1, line 2, neutral, and ground.

The Line 1 buss has one leg of the heating element, and that's it.

The Line 2 buss has the other leg of the heater element, and the 110V hot-side wires (pump, vent fan, etc.).

The neutral buss has all the 110V neutrals.

The ground buss has... well... the grounds.

My problem is, my Line 2 buss is full, and I still need one more 110V circuit for the PID. Can I just connect the hot side to the Line 1 buss (and the other side to the neutral)? Or do all the 110V hots need to come from the same line?

It should be fine to connect to the Line 1 bus.

Lines 1 and 2 are essentially 110V lines running with opposite phase. When they are combined they net 220V, but individually they are 110V relative to the neutral.

As long as you don't overload your circuit breaker you should be fine.

Cool. I wasn't sure if the phase difference mattered.

If you look at your house breaker panel, you should see something similar to what you're suggesting. There are two hot lines, the circuits are typically balanced between Hot 1 and Hot 2.