Engine Thermal Switch

This switch is actuated by engine coolant temperature and v/ill open when coolant reaches 140°F. Switch controls heater delay relay and at lower temperatures (with switch closed), relay will be energized and relay contacts will be held open. In cool weather when heating is called for, this will delay starting of system until coolant warms up to 140°F, to prevent excessive amounts of cold air being delivered through heater outlets. Opening of the switch contacts and de-energizing of the heater delay relay winding will allow relay contacts to close and provide a ground for the control head and for the lo relay winding.