I dont know your particular machine.... but much would be in common with other commercials (like mine)....
If the pump keeps running and trying to fill the boiler (Im assuming here it is plumbed in) then the water level sensor is probably covered with scale.... it is therefore insulated.... and doesnt detect when there is sufficient water in the boiler. There should be a sight glass.... a tube with a little floating ball which shows the water level - this should be between Min and Max (normally on the tube or alongside the tube). If it is overfilling the boiler, get the water sensor cleaned (or do it yourself if you feel confident to tackle that job) ASAP!!!!.
The gauge showing 1.5 to 2 bar would be steam pressure (which mostly is about 1.1 Bar when up to full steam). The other gauge would be brew pressure.... and that will show normal mains pressure - about 3.5 - 4.5 Bar at rest and 9 Bar when extracting espresso.
Now if it isnt plumbed... but you are drawing water from a tank - many pumps need positive pressure on the supply side (about 3.5 Bar) for them to work properly.... The pump might not be able to suck enough water to fill the boiler properly (and could be damaged if you continue to use it that way).
And if you cant see the water level in the indicator..... dont turn the machines heaters on..... the water level might be low...... resulting in a burnt out heater element!
New elements $100 or so..... new pumps are $200-250 - damaging either can wipe the smile right off your face :(
Hope that helps.