A siphon guard 16 includes a housing 30 having an inlet 32 and an outlet 34. A primary flow path 36 is disposed within the housing and is in fluid communication with the inlet and the outlet. A secondary flow path 38 is disposed within the housing and is in fluid communication with the inlet and the outlet. The secondary flow path has a higher resistance to fluid flow than the primary path. A valve 40 is disposed within the primary flow path. The valve has a valve seat 42 and a first ball 44 and a second ball 46. The first and second balls are movable by gravity between a valve closed position and a valve open position. The first ball is disposed between the second ball and the valve seat.
