Control device and pump apparatus

A retrofitting pump kit comprising:

• a controller for a pump, the pump being a mechanically switched, constant-speed pump, the controller comprising:
• an electric current sensor measuring electric current drawn by the pump, and
• at least one switch being adapted to selectively direct the pump among three conditions consisting of:
• (i) stop, (ii) a constant-speed forward direction, and (iii) a constant-speed reverse direction;
• the retrofitting pump kit further comprising a current range including a minimum operating current and a maximum operating current, each being measured during unblocked pump operation,
• the controller characterized by:
• while the current is above a first pre-determined value, the first pre-determined value being measurably greater than maximum current, the controller directs the at least one switch to complete a series of cycles, each cycle comprising (a) stopping by stopping power to the pump and allowing it to coast to a rest, (b) operating in the constant-speed reverse direction, (c) stopping by stopping power to the pump and allowing it to coast to a rest, and (d) operating in the constant-speed forward direction, with a user-adjustable stopping period between direction changes;
• and
• while the number of cycles is less than or equal to a pre-determined maximum number of cycles, the controller directs the switch to cycle, until the current is below a second pre-determined value, where the second pre-determined value is measurably less than the first pre-determined value.

A method of operating a mechanically switched, constant-speed pump, comprising:

• monitoring the current drawn from a mechanically switched, constant-speed pump while operating in a constant-speed forward direction, to detect whether the current exceeds a first pre-determined value which is measurably greater than a maximum current of a current range measured during unblocked pump operation;
• controlling a direction of the motor among three conditions consisting of:
• (i) stop, (ii) the constant-speed forward direction, and (iii) a constant-speed reverse direction;
• directing, while the current is above a first pre-determined value, the first pre-determined value being measurably greater than the maximum current, the controller directs the at least one switch to complete a series of cycles, each cycle comprising (a) stopping by stopping power to the pump and allowing it to coast to a rest, (b) operating in the constant-speed reverse direction, (c) stopping by stopping power to the pump and allowing it to coast to a rest, and (d) operating in the constant-speed forward direction, with a user-adjustable stopping period between direction changes;
• and
• directing, while the number of cycles is less than or equal to a pre-determined maximum number of cycles, the controller directs the switch to cycle, until the current is below a second pre-determined value, where the second pre-determined value is measurably less than the first pre-determined value.