Refrigerant pump down for an HVAC system

Patent metadata

Field	Value
Publication number	US-10767882-B2
Application number	US-201816163260-A
Country	US
Kind code	B2
Filing date	Oct 17, 2018
Priority date	Oct 17, 2018
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

In one embodiment, an HVAC system includes an indoor unit having an indoor blower, an outdoor unit having a compressor and a condenser, an isolation valve coupled to the outdoor unit, and a sensor to detect a refrigerant leak. The HVAC system further includes one or more controllers operable to generate an alarm in response to the sensor detecting the refrigerant leak, operate the indoor blower in response to generating the alarm, close the isolation valve in response to generating the alarm, and operate the compressor to pump down the refrigerant to the condenser in response to generating the alarm.

First claim

What is claimed is:

1. A heating, ventilation, and air conditioning (HVAC) system, comprising:
an indoor unit comprising an indoor blower;
an outdoor unit comprising a compressor and a condenser;
an isolation valve coupled to the outdoor unit;
a sensor operable to detect a leak of refrigerant; and
one or more controllers operable to:
generate an alarm in response to the sensor detecting the refrigerant leak;
operate the indoor blower in response to generating the alarm;
close the isolation valve in response to generating the alarm;
operate the compressor to pump down the refrigerant to the condenser in response to generating the alarm;
determine that the alarm has been deactivated;
determine that a heating mode of the HVAC system has been initiated;
generate a second alarm in response to the sensor detecting the refrigerant leak after determining that the heating mode of the HVAC system has been initiated; and
shut down the heating mode in response to generating the second alarm.

2. The HVAC system of claim 1 , wherein the one or more controllers are further operable to:
increment a count of the alarm by one in response to generating the alarm;
determine that the count of the alarm is above a predetermined threshold; and
generate a critical alarm in response to determining that the count of the alarm is above the predetermined threshold.

3. The HVAC system of claim 1 , wherein:
the valve is a liquid solenoid valve; and
the refrigerant is A2L refrigerant.

4. The HVAC system of claim 1 , wherein the one or more controllers are further operable to determine whether a cooling mode of the HVAC system has been locked out, wherein a heating mode of the HVAC system is not locked out due to the detected refrigerant leak.

5. A heating, ventilation, and air conditioning (HVAC) system, comprising:
an indoor unit comprising an indoor blower;
an outdoor unit comprising a compressor and a condenser;
an isolation valve coupled to the outdoor unit;
a sensor operable to detect a leak of refrigerant; and
one or more controllers operable to:
generate an alarm in response to the sensor detecting the refrigerant leak;
operate the indoor blower in response to generating the alarm;
close the isolation valve in response to generating the alarm;

operate the compressor to pump down the refrigerant to the condenser in response to generating the alarm;
determine that the alarm has been deactivated;
determine that a cooling mode of the HVAC system has been initiated;
open the isolation valve in response to determining that the cooling mode has been initiated;
determine that the cooling mode of the HVAC system has been deactivated;
determine that one or more predetermined weather conditions have been satisfied in response to determining that the cooling mode has been deactivated; and
run the compressor to pump down the refrigerant to the condenser in response to determining that the one or more predetermined weather conditions have been satisfied.

6. A method, comprising:
detecting, by a sensor of a heating, ventilation, and air conditioning (HVAC) system, a leak of refrigerant;
generating an alarm in response to the sensor detecting the refrigerant leak;
operating an indoor blower of an indoor unit of the HVAC system in response to generating the alarm;
closing an isolation valve coupled to an outdoor unit of the HVAC system in response to generating the alarm;
operating a compressor of the outdoor unit to pump down the refrigerant to a condenser of the outdoor unit in response to generating the alarm;
determining that the alarm has been deactivated;
determining that a heating mode of the HVAC system has been initiated;
generating a second alarm in response to the sensor detecting the refrigerant leak after determining that the heating mode of the HVAC system has been initiated; and
shutting down the heating mode in response to generating the second alarm.

7. The method of claim 6 , further comprising:
incrementing a count of the alarm by one in response to generating the alarm;
determining that the count of the alarm is above a predetermined threshold; and
generating a critical alarm in response to determining that the count of the alarm is above the predetermined threshold.

8. The method of claim 6 , wherein:
the isolation valve is a liquid solenoid valve; and
the refrigerant is A2L refrigerant.

9. The method of claim 6 , further comprising determining whether a cooling mode of the HVAC system has been locked out, wherein a heating mode of the HVAC system is not locked out due to the detected refrigerant leak.

10. A method, comprising:
detecting, by a sensor of a heating, ventilation, and air conditioning (HVAC) system, a leak of refrigerant;
generating an alarm in response to the sensor detecting the refrigerant leak;
operating an indoor blower of an indoor unit of the HVAC system in response to generating the alarm;
closing an isolation valve coupled to an outdoor unit of the HVAC system in response to generating the alarm;
operating a compressor of the outdoor unit to pump down the refrigerant to a condenser of the outdoor unit in response to generating the alarm;
determining that the alarm has been deactivated;
determining that a cooling mode of the HVAC system has been initiated;
opening the isolation valve in response to determining that the cooling mode has been initiated;
determining that the cooling mode of the HVAC system has been deactivated;
determining that one or more predetermined weather conditions have been satisfied in response to determining that the cooling mode has been deactivated; and
operating the compressor to pump down the refrigerant to the condenser in response to determining that the one or more predetermined weather conditions have been satisfied.

11. One or more computer-readable storage media embodying instructions that, when executed by a processor, cause the processor to perform operations comprising:
detecting, by a sensor of a heating, ventilation, and air conditioning (HVAC) system, a leak of refrigerant;
generating an alarm in response to the sensor detecting the refrigerant leak;
operating an indoor blower of an indoor unit of the HVAC system in response to generating the alarm;
closing an isolation valve coupled to an outdoor unit of the HVAC system in response to generating the alarm;
operating a compressor of the outdoor unit to pump down the refrigerant to a condenser of the outdoor unit in response to generating the alarm;
determining that the alarm has been deactivated;
determining that a heating mode of the HVAC system has been initiated;
generating a second alarm in response to the sensor detecting the refrigerant leak after determining that the heating mode of the HVAC system has been initiated; and
shutting down the heating mode in response to generating the second alarm.

12. The one or more computer-readable storage media of claim 11 , wherein the operations further comprise:
incrementing a count of the alarm by one in response to generating the alarm;
determining that the count of the alarm is above a predetermined threshold; and
generating a critical alarm in response to determining that the count of the alarm is above the predetermined threshold.

13. The one or more computer-readable storage media of claim 11 , wherein:
the isolation valve is a liquid solenoid valve; and
the refrigerant is A2L refrigerant.

14. The one or more computer-readable storage media of claim 11 , wherein the operations further comprise determining whether a cooling mode of the HVAC system has been locked out, wherein

Assignees

• Lennox Ind Inc

Inventors

• Kowald Glenn William
• Berg Eric
• Goel Rakesh

Classifications

• F24F11/84

  using valves · CPC title

• F25B49/005 Primary

  of safety devices (F25B49/02 and F25B49/04 take precedence) · CPC title

• F24F11/36 Primary

  to leakage of heat-exchange fluid · CPC title

• F25B2600/2503

  Condenser exit valves · CPC title

• F25B2500/222

  Detecting refrigerant leaks · CPC title