Abstract: In a fluid circulation system of the type having a pump for supplying pressurized fluid to an apparatus requiring a supply of pressurized fluid, a sump containing a volume of fluid from which the pump draws its supply, and an overage fluid return line, a sump level maintenance system including a remote fluid reservoir disposed above the sump, a housing in communication with the fluid in the sump and defining a pair of ports in communication with respective ones of the reservoir and the overage return passage, a float structure operative to open both ports when the sump level is below a low level and to close the port to the reservoir to prevent replenishment when the sump level is between the low level and a high level and to close both ports when the sump level is above the high level to prevent overage fluid from returning to the sump, and a fluid conduit from the overage passage to the reservoir operative to divert overage to the reservoir when the second port is closed thereby depleting the fluid volume i