Abstract: A pump (B) pumps water from a swimming pool (A) to a forward/reverse direction control valve (D). The control valve (D) has a first or forward flow state in which it channels water into an inlet (20) of a filter (C) and from a filter outlet (24) back to the swimming pool and a second state in which it channels the water into the fluid outlet (24) and from the fluid inlet to a drain (28). A microprocessor based electronic control circuit (E) selectively actuates the pump at preselected intervals for preselected durations such that the water from the swimming pool is intermittently filtered. The control circuit further monitors the fluid pressure with a low pressure limit switch (46). In response to the pumped fluid pressure failing to achieve a low limit within a preselected duration, the control circuit terminates operation of the pump. Further, the control circuit monitors the water pressure with a high pressure limit switch (48).

Abstract: A circulating pump (B) pumps water between a swimming pool or other reservoir (A) and a filter or other circulated fluid receiving apparatus (C). A control circuit (D) intermittently operates the circulating pump. The operating circuit includes a first timer (32) and a cycle switch (34) which is cyclically closed to produce a pump signal for a first duration with a first periodicity. The pump signal starts a second timer (54) of a time controlled switch (52). The second timer holds the time controlled switch conductive for a preselected time period. The pump signal is conducted through a bypass switch (64), and the time actuated switch. When the pressure monitored by a pressure sensor (20) exceeds a preselected pressure, a low pressure switch (62) closes conducting the pump signal around the bypass and time controlled switches. A high pressure shutoff switch (66) conducts the pump signal to a power relay coil (72) unless a preselected high pressure is monitored.