Patent · US Expired

Blocked fan detection system for heat pump

US5528908A · kind A · utility

92Cited by
15References
12Claims
0Family size

Assignee

Inventors

Key dates

Filing dateJun 6, 1995
Grant dateJun 25, 1996
Priority date
Expiry dateJun 6, 2015

Classification

  • Technology area (CPC Y)Emerging Cross-Sectional Technologies
  • CPC primaryY02B30/70
  • WIPO fieldThermal processes and apparatus
  • WIPO sectorMechanical engineering

Abstract

The blocked fan or obstructed airflow condition is detected by measuring the difference between outdoor air temperature and outdoor exchanger coil temperature. If a very high difference is detected, or if no decrease in the difference is achieved after termination of the defrost cycle, and if either of these conditions persists over a plurality of defrost cycles, then the blocked condition is declared. The diagnostic system can be integrated in an existing demand defrost cycle and is capable of detecting blocked conditions attributable to foreign matter such as leaves, paper and debris which cannot be cleared by defrosting.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.