Not familiar with that particular unit, but some units have a float switch in the trap of the drain plumbing (to protect against condensate overflow). Upon a blockage the switch cuts off power to the unit. This switch can be bypassed, at least for testing if you don't have an ohmmeter. If there is a switch, just remove from the switch from the circuit and connect back the wires without the switch. switches are connected in series, power goes in one end and comes out the other.