Abstract: A HVAC diagnostic system and method is disclosed which permits bypassing the normal operation of a thermostat by HVAC service personnel, typically permitting the HVAC service personnel control over thermostat functionality while servicing the condenser coils and/or compressor located external to customer building. The present invention is useful in situations where HVAC service calls must be scheduled at customer premises such as homes, apartments, etc., during normal hours where the occupants are not typically available to permit access to the thermostat within the building structure. By permitting override of the customer thermostat at the compressor/condenser unit, the system permits servicing of this unit without customer assistance. As such, HVAC service can be completed on a more regular schedule, saving substantial energy and providing improved customer environmental comfort.

Abstract: Disclosed is a machinery operator protection system and method, which inhibits the use of machinery unless the operator of the machinery is properly secured with a lanyard and/or body harness to the machinery. The disclosed system includes a lanyard connection detector for detecting proper attachment of at least one lanyard to a machinery operator and a lanyard interlock control for controlling a switch to selectively enable activation of the machinery when the lanyard connection detector indicates that the operator is properly attached to the machinery with the lanyard. The disclosed method includes the steps of: detecting when at least one safety lanyard is properly attached to a between a machinery operator and a piece of machinery; and inhibiting operation of the machinery unless proper operator safety lanyard attachment is detected.