RA3.  HERS Rater Compliance

The HERS Rater shall review the information submitted on the installation certificate and perform follow-up communications with the HVAC installer or the homeowner. The system complies if the HERS Rater determines the remedial actions have been performed, and the information reported on the installation certificate is valid.

RA3.2.3 Weigh-In Charging Procedure

This section specifies the weigh-in charging procedure in which the weight of the required refrigerant charge is determined by using the manufacturer's specifications for a standard refrigerant charge weight and taking into account adjustment factors such as deviations in refrigerant line length and diameter. The calculated weight of refrigerant is then installed using a refrigerant scale. RA3.2.3 provides two procedures: Section RA3.2.3.1 shall be used by the HVAC installer when the weigh-in procedure is required by the Standards for compliance.  Section RA3.2.3.2 shall be used by the HERS Rater when the Standards specify use of the procedure for compliance, or specify it as an optional procedure for compliance. The weigh-in charging procedure is an acceptable method for demonstrating compliance at any outdoor temperature, however if the weigh-in charging procedure is used, HERS verification of compliance cannot use group sampling.

HVAC installers shall use the weigh-in charging procedure in accordance with the space conditioning system manufacturer’s specifications.

RA3.2.3.1        HVAC Installer - Weigh-In Charging Procedure

Split system air conditioners are shipped from the factory charged with a standard amount of refrigerant as indicated on the nameplate. The manufacturer-supplied refrigerant charge is expected to be the correct amount for the system based on a standard liquid line length and diameter. It is the responsibility of the HVAC installer to ensure that the charge is correct for each air conditioner and to adjust the charge based on liquid line dimensions that deviate from the manufacturer's standard line specification.

RA3.       Procedure Options

There shall be two options for compliance using the weigh-in charging procedure: