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Refrigerant Charge Verifications (RCV) |
What are the requirements for airflow remediation?
During RCV (Refrigerant Charge Verification), if an existing duct system cannot achieve the minimum 300 cfm/ton airflow requirement, then the Installer must perform RA3.3.3.1.5.1 (airflow) Remedial Actions and the HERS Rater must verify that the Installer attempted each of the applicable steps. However, if at any time during the airflow remediation steps the system achieves =300 cfm/ton, then the remedial actions may be discontinued and the RCV may proceed using the measured airflow. Otherwise, after attempting all of the applicable steps, the system will be considered in compliance and the refrigerant charge verification shall proceed using the best airflow rate attained. Note: if the airflow remediation steps are used to demonstrate compliance with the minimum airflow requirements (measured airflow is never =300 cfm/ton), then an OCST (Occupant Controlled Smart Thermostat) must be installed as verified by the Building Official (not the HERS Rater). Achieving =300 cfm/ton during the remediation steps would eliminate the requirement for installation of an OCST. (VIEW MORE INFO) |
RA3.3.3.1.5.1 Remedial Actions The installer shall attempt to correct non-compliant system airflow by performing the following remedial actions:
When performing these remedial actions determines that there is a fault, a corrective action shall be performed if possible. In many cases, airflow can be improved by adding a return duct and filter grille, or enlarging the existing return duct or filter grille. Alteration of the return duct system is an alternative that shall be considered if applicable to the existing system, and if other remedial actions do not improve the airflow. Alteration of the return duct system to bring the system airflow rate into compliance is expected to be attainable for systems with ducts in an attic space with sufficient clearances for accommodating improvements to the return duct system. |