Abstract: A liquid filter, for example for a condensate reservoir (1), formed of a printed circuit board (8) comprising a plurality of holes (9) forming a filter screen through the printed circuit board. A first set of capacitive elements (16, 17) are formed in the printed circuit board (8) forming a first capacitive sensor (12) capable of measuring the depth of the liquid adjacent to the filter. The capacitive elements (16,17) may be shielded (19) on one side such that they measure the depth on one side of the filter. A second set of capacitive elements (16?, 17?) may be provided to measure the depth of the liquid on the opposite side of the filter.

Abstract: A condensate tray assembly for use below a condensate generating appliance, particularly a refrigeration unit. The assembly comprises a tray (1) with an inlet (3A) and an outlet (3) towards the bottom of the tray. A self-priming pump (5) is connected to the outlet for pumping liquid from the tray. A sensor (12) within the tray determines the rate of change of the depth of liquid. A control system (14) receives an input from the sensor (12) to control the pump (5) to pump liquid from the tray and to turn off the pump based on the rate of reduction of the depth of liquid in the tray. The invention also extends to a method of operating the pump.