Prosecution Insights
Last updated: April 18, 2026
Application No. 18/458,537

Safety System For Air Handling Unit

Final Rejection §103
Filed
Aug 30, 2023
Examiner
NIEVES, NELSON J
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Rheem Manufacturing Company
OA Round
2 (Final)
75%
Grant Probability
Favorable
3-4
OA Rounds
2y 7m
To Grant
91%
With Interview

Examiner Intelligence

Grants 75% — above average
75%
Career Allow Rate
583 granted / 778 resolved
+4.9% vs TC avg
Strong +16% interview lift
Without
With
+16.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
33 currently pending
Career history
811
Total Applications
across all art units

Statute-Specific Performance

§101
0.8%
-39.2% vs TC avg
§103
45.3%
+5.3% vs TC avg
§102
19.5%
-20.5% vs TC avg
§112
32.0%
-8.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 778 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Response to Amendment Applicant's amendments to the claims have been entered. Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1-4, 6-9, 11, 13-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Notara et al. (US 20220243939), hereinafter referred to as Notara, in view of Terry et al. (US 20050240312), hereinafter referred to as Terry, in view of Chen et al. (US 20160178229), hereinafter referred to as Chen. Re claim 1, 6 and 13, Notara teaches a safety system for an air handling unit (AHU) comprising a heating unit and a cooling unit, the safety system comprising: a refrigerant sensor (e.g. 770) coupled to the AHU (720), wherein the refrigerant sensor is configured to generate an input proportional to a concentration of a refrigerant leak sensed in the AHU (e.g. ¶ 116, “The A2L sensor 770 may be configured to send signals to the A2L control board 750 when an A2L refrigerant leak is detected”); an interface control relay module (e.g. 750) comprising: a refrigerant sensor input (e.g. 760 or 761) connected to the refrigerant sensor; a control unit (e.g. implicit by “control board”) coupled to the refrigerant sensor input and configured to receive the input from the refrigerant sensor; a first relay output and a second relay output (e.g. ¶ 136, “W1 wire relay 755 and the W2 wire relay 756”), each connecting the control unit to a cooling unit (e.g. 724, 727) of the AHU; a third relay output (e.g. ¶ 151, “the G wire”) connecting the control unit to a fan (e.g. 723) of the AHU; and wherein the control unit is configured to activate or deactivate at least one of the first relay output, the second relay output, the third relay output based on the input received from the refrigerant sensor (e.g. ¶ 136). Notara does not teach the limitation of a fourth relay output connecting the control unit to a damper of the AHU; wherein the control unit is configured to deactivate the fourth relay output when the concentration of the refrigerant leak is below a predefined threshold value. However, Terry teaches a control system for an AHU comprising a fourth relay output (e.g. ¶ 84, “RY4”) connecting a control unit (e.g. 30) to a damper (e.g. ¶ 84, “Output pin 5 of microcontroller 30 actuates relay RY4 for providing power switching for a damper of HVACR system 1”) of the AHU. Further, Chen teaches a control system that deactivates (closes) a damper (118) when a refrigerant leak is below a predefined threshold value (e.g. ¶ 42, “If the refrigerant concentration is not greater than the second predetermined concentration, at step 220, controller 130 stops operation of blower 114 and returns damper 118 to an internal circulation position”; see Fig 6). Therefore, at the time the invention was filed it would have been obvious for a person of ordinary skill in the art to have modified Notara and integrated a fourth relay output connecting the control unit to a damper of the AHU wherein the control unit is configured to deactivate the fourth relay output when the concentration of the refrigerant leak is below a predefined threshold value, as taught by Terry and Chen, in order to control the damper. Moreover, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by and/or obvious over the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device will perform the claimed process. Thus, the method, as claimed, would necessarily result from the normal operation of the apparatus. See MPEP 2112.02. Re claim 2, 7, Notara, as modified, teaches the interface control relay module of claim 1 and the safety system of claim 6. Notara further teaches wherein the control unit is configured to determine a degree of refrigerant leak based on comparing the concentration of the refrigerant leak to a predefined threshold value (e.g. claim 10, “wherein the first A2L sensor is configured to communicate with the A2L control board if the first A2L sensor detects that the amount of A2L refrigerant exceeds a leak threshold, and wherein the second A2L sensor is configured to communicate with the A2L control board if the second A2L sensor detects that the amount of leaked A2L refrigerant exceeds a leak threshold”). Re claim 3, 8, Notara, as modified, teaches the interface control relay module of claim 2 and the safety system of claim 7. Notara further teaches wherein the control unit is configured to deactivate the third relay output when the concentration of the refrigerant leak is below the predefined threshold value (e.g. ¶ 38, “Further, in the event that an A2L refrigerant leak is detected, the second relay 155 is closed such that the blower motor 123 may receive the 24 volt A/C power even though the rest of the HVAC system is shut down”). Re claim 4, 9, 17, Notara, as modified, teaches the interface control relay module of claim 1 and the safety system of claim 6. Notara does not teach the limitation of wherein the interface control relay module further comprises a fifth relay output and a sixth relay output, each connected to the heating unit, wherein the control unit is configured to activate or deactivate the fifth relay output and the sixth relay output to turn on or turn off the heating unit. However, the examiner takes official notice of the fact that using two relays for a heating unit wherein a controller controls the relays to turn on/off the heating unit. Therefore, at the time the invention was filed it would have been obvious for a person of ordinary skill in the art to have modified Notara and integrated wherein the interface control relay module further comprises a fifth relay output and a sixth relay output, each connected to the heating unit, wherein the control unit is configured to activate or deactivate the fifth relay output and the sixth relay output to turn on or turn off the heating unit, in order to control the heating unit. Moreover, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by and/or obvious over the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device will perform the claimed process. Thus, the method, as claimed, would necessarily result from the normal operation of the apparatus. See MPEP 2112.02. Re claim 11, Notara, as modified, teaches the safety system of claim 7. Notara further teaches further comprising a processing unit configured to monitor the interface control relay module and trigger an alert when the refrigerant leak is detected (e.g. ¶ 99, “Closing the alarm relay 559 will cause the alarm on the A2L control panel 550 to be powered on, which will include, at least, turning on the buzzer 562 and the LED 563 to give auditory and visual alerts that a leak has been detected”). Re claim 14, Notara, as modified, teaches the method of claim 13. Notara further teaches further comprising, deactivating the first relay output and the second relay output, and stopping operation of the cooling unit when the concentration of the refrigerant leak exceeds the predefined threshold value (e.g. ¶ 136, “the A2L control board 750 may be configured to cut off power to all parts of the indoor unit 720 except the blower motor 723 by opening at least the W1 wire relay 755 and the W2 wire relay 756 and closing at least the G wire relay 754. Opening the W1 wire relay 755 and the W2 wire relay 756 will ensure that all heating functions are shut off”). Re claim 15, Notara, as modified, teaches the method of claim 13. Notara further teaches further comprising, activating at least one of the third relay output and the fourth relay output to initiate the fan or the damper, and dispersing the leaked refrigerant (e.g. ¶ 32, “More specifically, in one or more embodiments, if a leak is detected, the A2L control board 150 may be configured to cut off power to the indoor control board 126 by opening the first relay 153, while directing power directly to the blower motor 123 by closing the second relay 155”). Claim(s) 5, 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Notara, in view of Terry, in view of Chen, in view of Hirai (US 20220214062), hereinafter referred to as Hirai. Re claim 5 and 12, Notara, as modified, teaches the safety system of claim 7. Notara does not teach the limitation of further comprising an airflow sensor of the AHU, the airflow sensor configured to generate an input indicative of an amount of airflow produced by the fan. However, Hirai teaches a control system for an AHU comprising an airflow sensor of the AHU, the airflow sensor configured to generate an input indicative of an amount of airflow produced by the fan (see ¶ 37, “The supply airflow volume detection unit 37 and the exhaust airflow volume detection unit 38 may be airflow volume sensors that detect the airflow volume of the supply air fan 34 and the exhaust fan 35. If the airflow volume sensor is used, the airflow volume equivalent value may be, for example, a voltage value corresponding to the airflow volume”). Therefore, at the time the invention was filed it would have been obvious for a person of ordinary skill in the art to have modified Notara, as modified, and integrated a smoke detector alarm, wherein the control unit is configured to trigger the smoke detector alarm when the refrigerant leak is detected, as taught by King, in order to alert the user of any smoke. Claim(s) 10, 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Notara, in view of Terry, in view of Chen,` in view of King (US Pat No. 7,005,994), hereinafter referred to as King. Re claim 10 and 18, Notara, as modified, teaches the safety system of claim 7. Notara does not teach the limitation of further comprising a smoke detector alarm, wherein the control unit is configured to trigger the smoke detector alarm when the refrigerant leak is detected. However, King teaches a control system for an AHU comprising a smoke detector alarm, wherein the control unit is configured to trigger the smoke detector alarm when the refrigerant leak is detected (see C3-lns 20-25, “If smoke is detected (step 40), the system will sound a corresponding smoke alarm (step 46) which may be unique to the detection of smoke”). Therefore, at the time the invention was filed it would have been obvious for a person of ordinary skill in the art to have modified Notara, as modified, and integrated a smoke detector alarm, wherein the control unit is configured to trigger the smoke detector alarm when the refrigerant leak is detected, as taught by King, in order to alert the user of any smoke. Moreover, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by and/or obvious over the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device will perform the claimed process. Thus, the method, as claimed, would necessarily result from the normal operation of the apparatus. See MPEP 2112.02. Response to Arguments Applicant’s arguments with respect to claim(s) 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to NELSON NIEVES whose telephone number is (571)270-0392. The examiner can normally be reached Monday to Friday 9am to 5pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Frantz Jules can be reached at 571-272-6681. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /NELSON J NIEVES/Primary Examiner, Art Unit 3763 4/3/2026
Read full office action

Prosecution Timeline

Aug 30, 2023
Application Filed
Aug 18, 2025
Non-Final Rejection — §103
Jan 20, 2026
Response Filed
Apr 03, 2026
Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12595930
AN HVAC SYSTEM AND RELATED METHODS
2y 5m to grant Granted Apr 07, 2026
Patent 12595939
DILUTION REFRIGERATION DEVICE AND METHOD
2y 5m to grant Granted Apr 07, 2026
Patent 12595118
HIGH-SURFACE AREA THERMAL PROTECTION MODULES FOR CARGO CONTAINERS AND CARGO CONTAINERS INCLUDING THE SAME
2y 5m to grant Granted Apr 07, 2026
Patent 12595944
A METHOD FOR CONTROLLING A VAPOUR COMPRESSION SYSTEM WITH A RECEIVER COMPRESSOR
2y 5m to grant Granted Apr 07, 2026
Patent 12598951
WAFER PLACEMENT TABLE
2y 5m to grant Granted Apr 07, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

3-4
Expected OA Rounds
75%
Grant Probability
91%
With Interview (+16.1%)
2y 7m
Median Time to Grant
Moderate
PTA Risk
Based on 778 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month