The “Element??” fault is determined by measuring the temperature rise over a set period. The fault indicates that the system has tried to heat the tank but it did not heat within the pre-set 1 hour 30 minutes allowed.
The pump out option on the Grease Boss 216 can be used to occasionally empty and flush out the unit, it may also reduce the frequency of external pump outs. You may want to do this to eliminate odour or sludge build up, however the usual daily maintenance on the grease trap is still required.