US5801940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fault-tolerant HVAC system
Assignee: HVAC MODULATION TECHNOLOGIES LLC
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Filing: 1996-02-12
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Granted: 1998-09-01
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Expires: 2016-02-12
Abstract
Abstract A fault-tolerant HVAC system capable of continued operation in the event of a thermostat malfunction. An HVAC controller controls the operation of an HVAC unit in accordance with a temperature signal output from the thermostat and indicative of air temperature of a conditioned space proximate the thermostat. The HVAC controller detects a thermostat malfunction and, in response thereto, instead controls the operation of the HVAC unit in accordance with a temperature sensor outputting a signal indicative of return air temperature from the conditioned space.
Inventors
- 👤 Robert M. Russ
- 👤 William W. Bassett
- 👤 Charles A. Glorioso
- 👤 Nir Merry
- 👤 Larry A. Lincoln
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:52
CPC Classifications
G; G01; G01D; G01D4/00; G01D4/002; G01D4/006; G01D4/004; G05; G05D; G05D23/00; G05D23/19; G05D23/1927; G05D23/193; G05D23/1932; G05D23/1934; Y; Y02; Y02B; Y02B70/00; Y02B70/30; Y02B90/00; Y02B90/20; Y04; Y04S; Y04S20/00; Y04S20/20; Y04S20/242; Y04S20/244; Y04S20/30
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
246 words
An HVAC system capable of continued operation following a thermostat malfunction, the HVAC system comprising: a thermostat having an output signal indicative of air temperature of a conditioned space proximate the thermostat; an HVAC unit having a heat exchanger, a blower for drawing air through the heat exchanger, and at least one of a heating unit and a cooling unit for modifying the temperature of air circulating through the heat exchanger; a discharge air plenum coupling the HVAC unit to the conditioned space, the discharge air plenum providing a path for air discharged from the HVAC unit to be expelled into the conditioned space; a return air plenum coupling the conditioned space to the HVAC unit, the return air plenum providing a path for return air from the conditioned space to an inlet port of the HVAC unit; a temperature sensor having an output signal indicative of return air temperature; an HVAC controller coupled to the thermostat, the temperature sensor, and the HVAC unit; means within the HVAC controller for sensing the output signal of the thermostat and for modifying air temperature within the conditioned space based upon the output signal of the thermostat; means within the HVAC controller for detecting a malfunction of the thermostat; and means within the HVAC controller for sensing the output of the temperature sensor and for modifying air temperature within the conditioned space based upon the output signal of temperature sensor, in response to detecting a malfunction of the thermostat.
Claim 2
Dependent Claim
246 words
An HVAC system capable of continued operation following a thermostat malfunction, the HVAC system comprising: a thermostat having an output signal indicative of air temperature of a conditioned space proximate the thermostat; an HVAC unit having a heat exchanger, a blower for drawing air through the heat exchanger, and at least one of a heating unit and a cooling unit for modifying the temperature of air circulating through the heat exchanger; a discharge air plenum coupling the HVAC unit to the conditioned space, the discharge air plenum providing a path for air discharged from the HVAC unit to be expelled into the conditioned space; a return air plenum coupling the conditioned space to the HVAC unit, the return air plenum providing a path for return air from the conditioned space to an inlet port of the HVAC unit; a temperature sensor having an output signal indicative of return air temperature; an HVAC controller coupled to the thermostat, the temperature sensor, and the HVAC unit; means within the HVAC controller for sensing the output signal of the thermostat and for modifying air temperature within the conditioned space based upon the output signal of the thermostat; means within the HVAC controller for detecting a malfunction of the thermostat; and means within the HVAC controller for sensing the output of the temperature sensor and for modifying air temperature within the conditioned space based upon the output signal of temperature sensor, in response to detecting a malfunction of the thermostat.
Claim 3
Dependent Claim
23 words
The HVAC system according to claim 1 further including at least one positionable air damper associated with at least the discharge air plenum.
Claim 4
Dependent Claim
32 words
The HVAC system according to claim 2 further including means to position at least one of the positionable air damper in an open orientation upon detection of a malfunction of the thermostat.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-31 | 2002-03-02 | 2002-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-31 | 2006-03-02 | 2006-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-31 | 2010-03-02 | 2010-09-01 | $7700.00 | Window Closed / Lapsed |