Recirculating fluid pump control system

Abstract

A recirculating hot water system includes a hot water supply pipe and a hot water return pipe connected in a loop between a hot water outlet of a hot water tank and a return inlet to that tank. An electrically controlled recirculating pump is placed in the return pipe between the inlet to the hot water tank and the supply pipe which has hot water taps located at various points along it. Manually operated push buttons are located adjacent at least some of these hot water taps to operate a time delay circuit, which turns on the recirculating pump for a pre-established time interval determined by the parameters of the time delay circuit. Thus, the recirculating pump is turned on only when there is a demand for hot water circulating through the system. To prevent unnecessary operation of the pump, a thermostatically controlled switch may be coupled to the return pipe to override any signals from the time delay circuit and prevent the pump from operating if the water in the return pipe is at or above some minimum temperature determined by the setting of the thermostat.

Dependencies are inferred from the claim text.