Heat Strips Sail Switches

This switch is seen primarily in commercial units, and, in my opinion, it is a valuable safety switch for heating and cooling. It is usually located downstream of the evaporator fan. General low voltage control circuits mounted sail through the switch. Y terminal (cooling and, as a rule, are connected to the compressor) or W terminal (heating and used electric furnaces) are connected in series, sail through the switch. On Fig. 10-5 sail switch shown. There must be a certain volume of air blowing across the sail switch to close its circuit. Diaphragm type pressure switch can be used. They are found in some light commercial applications. This element, if the filter is dirty or broken fan belt, or fan motor is not running, the system will not work to prevent possible damage to any of its components. In units not equipped with limit switches, this type of switch is invaluable.

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