PRESSURE WASHER WITH DUTY CYCLE TEMPERATURE CONTROLLER AND METHOD

摘要

A pressure washer for use by an operator. A heat exchanger has a water input adapted to connect to a water source and has a water output providing discharge water. A water pump supples water to the heat. A temperature selector is responsive to operator. A burner in thermodynamic communication with the heat exchanger applies heat to the heat exchanger and the water in the heat exchanger. The burner has a fuel input connecting a fuel source to the burner. A fuel switch selectively allows fuel from the fuel source to be supplied to the combustion chamber via the fuel input. A duty cycle timer has a uniform duty cycle and is energized when water flows through the heat exchanger. The duty cycle timer is responsive to the temperature selection switch to vary its duty cycle as a function of the operator input provided to the temperature selector. The duty cycle timer controls the fuel switch to supply fuel to the combustion chamber according to the duty cycle of the duty cycle timer whereby the duty cycle timer controls the burner and thereby controls temperature of the water in the heat exchanger. Preferably, the duty cycle has a minimum on time to maintain burner efficiency.