Lx30h hobart dw. booster will not turn on. element

The booster heat control circuit is controlled by the relay board. Visually check for loose or burnt relay contacts...
You will see the booster LED light when it calls for heat. Some newer machines have a second high limit on the right hand side of the booster tank.
It may be your control board is configured for low temp with no booster. When you power up, the display should say LX30H. If not
Pull open the upper drawer, place a magnet over the door interlock switch.

CAUTION, 220 volt power is present. be carefull what you touch.

on control board, short J5-1 and J5-2, then power up. You are in factory setup. press select on the control board to see each option on the front panel., press up arrow on control board to step up through options for each step. when done, press the off button on front panel. remove short and start up normally. With the magnet in place, AND THE DOOR CLOSED, run the machine and observe the relay board status lights.
If you want to adjust the temp set points, with the machine off, press and hold the hidden key behind the front panel logo, and press select on the control board.. Or on power up, hold the wask key..Same to adjust options as above. Press off to exit.