Patent ID: 7931447

Claim:
A method for controlling a fluid containment and circulation system having a fluid receptacle with a fluid outlet through which fluid exits the receptacle, a fluid inlet for returning fluid to the receptacle, a pump that moves the fluid from the fluid outlet through a filter to the fluid inlet, a suction conduit providing fluid communication between the fluid outlet and the pump and a return conduit providing fluid communication between the pump and the fluid inlet, a vacuum sensor for sensing a level of vacuum present in the suction conduit and producing a corresponding output, a vent valve having at least two positions, a first position which fluidly connects the suction conduit to matter outside the suction conduit and a second position which isolates the suction conduit from matter outside the suction conduit and a programmed computer, comprising the steps of: (A) storing at least one vacuum criteria and an operator-determined pump schedule in said computer; (B) receiving the output of said vacuum sensor in said computer; (C) comparing the vacuum sensor output to the at least one vacuum criteria; (D) selectively generating control outputs to said vent valve as determined by the computer to determine the position of said vent valve and to control the operation of the pump, based upon said vacuum sensor output; (E) periodically checking the time and comparing it to the pump schedule to determine an operator-determined operational state of the pump for that time and controlling the operational state of the pump accordingly, the pump having a plurality of running speeds for passing the fluid through the filter at a plurality of different rates, the operational state of the pump including the speed at which the pump runs, said at least one vacuum criteria having a plurality of values, a first corresponding to a first running speed of the pump and a second corresponding to a second running speed of the pump.