Diagnostics for a heating and cooling system
US5623834A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 1995 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | May 3, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25B2700/21152
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
Compressor discharge temperature, ambient outdoor air temperature and thermal load are used as control parameters for controlling the expansion valve setting and indoor fan speed. Diagnostics monitor a feedback signal from the fan motor to detect fan over-speed and increased speed due to decreased air flow caused by a dirty indoor air filter. Discharge pressure of the compressor is monitored to detect a blocked outdoor fan. The difference between actual and optimum compressor discharge temperatures and suction pressure of the compressor are monitored to detect a stuck-closed expansion valve or low refrigerant charge. Compressor "short-cycling" is limited to prevent reduced reliability of the compressor. The difference between compressor discharge temperature and outdoor coil temperature is measured before and after startup to detect compressor failure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.