Circulator pump check valve

A hydronic circulator for circulating fluid, the circulator comprising:

• a wet-rotor circulator motor, the circulator motor comprising
• a motor housing,
• a stator disposed within the motor housing and sealed from the circulating fluid,
• a rotor housing disposed within the motor housing within the stator, the rotor housing being unsealed from the circulating fluid so that the fluid enters the rotor housing,
• a rotor disposed within the rotor housing and in contact with the fluid, and
• an impeller affixed to one end of the rotor, the stator and rotor configured with respect to one another so that the rotor is caused to rotate when the stator is energized;
• an impeller casing fastened to the motor housing, the impeller casing comprising
• an inlet end for accepting the circulating fluid flowing into the impeller casing,
• an impeller zone into which the impeller extends from the motor, the impeller zone having an eye portion through which fluid is drawn into the impeller zone from the inlet end of the impeller casing, and
• an outlet end for discharging the circulating fluid flowing from the impeller casing;
• and
• a check valve positioned at said eye portion so that fluid flowing from the inlet end passes through the check valve before reaching the impeller, said check valve impeding flow in a reverse direction from the impeller zone to the inlet end.