Abstract: A system for remotely monitoring and controlling an HVAC device includes a server which receives queries from an entry device and data from the HVAC device. Databases with information regarding the location and status of the HVAC devices reside on the server, as does a user name/password file, instead of in the entry device or the HVAC controller. Connection is provided over various communications links including the Internet, POTS, and GSM networks. A user with an entry device such as a handheld computer or cell phone using wireless access protocol (WAP) can change settings, obtain diagnostic information, and receive alarm messages about a plurality of HVAC devices.

Abstract: A system for verifying the operability of one or more HVAC devices in a communication network includes a network control device that sends a particular type of message to the HVAC devices. Each HVAC device receiving the message will initiate a clearly visible display on the HVAC device if the message is appropriately processed within the receiving HVAC device. Each HVAC device may be visually checked to confirm that it is in fact responding to the message from the network control device.

Abstract: An electronic system for monitoring the condition of the filter in an HVAC unit includes a controller which issues at least one command to a circuit for the motor of the fan producing airflow through the filter. The command to the driver circuit is associated with a desired run speed for the fan. The controller is operative to compute the speed of the fan following issuance of the command to the motor drive circuit. This computed speed is compared to a predetermined fan speed that would normally occur when the filter is dirty. The electronic system is operative to generate a warning in the event that the computed fan speed does not compare favorably with the predetermined fan speed.

Abstract: An HVAC system is assigned a network identification for subsequent use within a communication network upon receipt of a formatted signal containing the network identification. The HVAC system stores the network identification in nonvolatile memory. The HVAC system also preferably stores a verification image of the communicated network identification so that any reading back of the network identification can be validated through comparison with the stored verification image.

Abstract: HVAC control information is stored in a memory associated with a programmable processor in such a manner as to be recallable in a potentially high electrical noise environment. The HVAC control information is stored along with corresponding verification images in particular memory locations. The verification images for at least some of the HVAC control information have unique mathematical relationships with respect to the stored pieces of HVAC control information.

Abstract: HVAC control information is written in a particular manner to a memory associated with a programmable processor. The processor generates verification images of the information and stores the same along with the information in addressable memory locations. The stored information and its corresponding verification images is read back for verification as to having been correctly stored in addressable memory locations. A rewriting and rereading of the information and the respective verification images can occur up to a predetermined number of times if necessary to verify that the information and respective verification images have been correctly stored.

Abstract: A device for reading and transmitting control parameter selections to a control system for an HVAC system is disclosed. The device is activated by the control system which receives the encoded control parameter selections. The activation is preferably accomplished by switching a power supply on and off that is associated with the reading and transmitting device.

Abstract: System and process are disclosed for selecting a range or configuration of refrigerants that may thereafter be used by a refrigerant recovery system in the recovery of one or more of the refrigerants. The recovery of refrigerants may occur at anytime after a range has been selected including a time during which the refrigerant recovery system has been switched off and back on again.

Abstract: A Network Management Control System for a multi-space building having individual space heating and cooling units in each space that ties the individual heating and cooling units together with a central computer which allows the remote computer to interrogate and overwrite parameters set at each local heating and cooling unit.

Abstract: A defrost cycle for a heat pump system which optimizes the efficiency of the heat pump by initiating defrost depending upon the relationship of both the outdoor coil ambient temperature and the outdoor coil refrigerant temperature with a predetermined temperature reference level.

Abstract: A space temperature control which prevents overshoot and undershoot of a desired space temperature by adjusting a subsequent sensed space temperature as a function of a previous sensed maximum space temperature to deenergize a space conditioning device at the adjusted temperature to maintain the desired space temperature.

Abstract: A adjustable defrost cycle for a heat pump system which ensures that the outdoor coil is maintained free of frost by adjusting a defrost initiation reference level for the initiation of the next subsequent defrost cycle depending upon the time period of the previous defrost cycle.