Patent ID: 6196246
Filing Date: 2001-03-06
Classification: E03B,E03C,Y10T

Abstract:
A freeze-resistant plumbing system comprising:a service pipe for supplying water from a water main pipe to at least one water fixture in a structure;a housing with at least one check valve installed between said service pipe and said water main pipe;a first circulation pump connected in line with said service pipe, the circulation pump having an outlet and an inlet;a closed cold water system loop disposed between the outlet and the inlet of the first circulation pump;an ambient temperature-sensing means which activates said first circulation pump upon sensing an ambient temperature below a predetermined value, causing water untapped by the fixture to circulate continuously through the closed cold water system loop from the outlet to the inlet of the circulation pump at a desired rate to prevent freezing of said water, further causing said check valve to close when circulating water pressure exceeds water pressure in the service pipe, thereby preventing water from flowing back through the service pipe to the water main pipe;a relief valve assembly in said housing downstream of said check valve disposed in a reverse flow direction, said relief valve assembly having dimensions sufficiently large enough to empty said service pipe and further having a port open to outside atmosphere and a relief valve operable to open position automatically in response to a high pressure condition in said service pipe which exceeds a predetermined value, which causes said relief valve to open, thereby discharging water under high pressure to the outside atmosphere through said port.