CMFRT3: Verify proper refrigerant charge and total system airflow within 20% of design air flow

Purpose

Verifying correct refrigerant charge helps ensure that the equipment operates at maximum efficiency and decreases the likelihood of premature equipment failure.

Criteria 

• Perform refrigerant charge test to ensure appropriate charge for HVAC equipment with subcooling deviation ±3°F or superheat deviation ±5°F. 
• Perform system airflow test using a flow hood, anemometer or other EarthCraft approved equivalent to ensure total system airflow is within 20% of the design airflow.

Clarifications

This requirement may be met by methods according to ACCA 5 QI-2007: 

• Superheat method test measurement within 5% of the manufacturer-recommended charge 
• Sub-cooling method test measurement within 3% of the manufacturer-recommended charge 
• Other equivalent method/tolerance approved by the equipment manufacturer

Geothermal heat pumps, mini-split heat pumps and hermetically sealed factory-charged stems may not be appropriate for standard subcooling or superheat refrigerant charge testing. To accommodate these system types, an OEM (original equipment manufacturer) test procedure may be used and documented.

Confirmation

Refrigerant Charge

• The builder must submit documentation demonstrating compliance of criteria to the EarthCraft Technical Advisor prior to submitting the project for certification 
• The EarthCraft Technical Advisor will review documentation provided by the builder for compliance of criteria.

Total System Airflow

• The EarthCraft Technical Advisor will diagnostically test compliance of criteria at the final inspection or be present to observe the test being completed by the HVAC contractor and confirm test results comply with criteria.