Flue pipe control

An improved flue pipe assembly for effecting heat transfer from a first fluid flowing through an interior of said flue pipe assembly to a second fluid surrounding an outer surface of said flue pipe assembly and for resisting heat transfer from said second fluid to said first fluid, said flue pipe assembly comprising:

• a first outer flue pipe having an inner surface and an outer surface, said outer surface being adapted to be in contact with said second fluid;
• a second inner flue pipe positioned within said first flue pipe and having an inner surface defining an interior space adapted to allow flow of said first fluid therethrough and an outer surface positioned in spaced opposed relationship to said inner surface of said first flue pipe to define a fluid flow space therebetween;
• and
• a valve assembly associated with said flue pipe assembly, said valve assembly being movable between a first open position in which said first fluid may flow through said fluid flow space and a second closed position in which fluid flow through said fluid flow space is restricted.

An improved flue pipe assembly for use in a fuel fired hot water heater comprising:

• an outer flue pipe adapted to form part of a reservoir of water to be heated by said water heater and having one end adapted to be positioned in overlying spaced relationship to a burner assembly of said water heater;
• an inner flue pipe positioned within said outer flue pipe and cooperating therewith to define an annular space between said inner and outer flue pipes, said annular space being open at opposite ends of said inner flue pipe;
• at least one opening adjacent said one end of said flue pipe assembly, said opening being adapted to allow combustion gases from said burner assembly to flow into said annular space;
• and
• a valve assembly positioned adjacent the other end of said flue pipe assembly, said valve assembly being operative to selectively open and close said open annular space at said other end of said flue pipe assembly to thereby resist air flow through said annular space when said burner assembly is in a standby mode.