Specifications

2008 Residential Appendices RA3-16
Appendix RA3 – Residential Field Verification and Diagnostic Test Protocols
c) If the difference is between minus 3°F and minus 100°F, then the measurement procedure shall be
repeated making sure that temperatures are measured in a manner that obtains the average
temperature in the airflow.
d) If the re-measured difference is between plus 3°F and minus 3°F the system passes the adequate
airflow criteria. If the re-measured difference is between minus 3°F and minus 100°F, the system
passes, but it is likely that the capacity is low on this system (it is possible, but unlikely, that airflow is
higher than average).
For the HERS Rater inspecting the system,
a) If the difference is between plus 4°F and minus 4°F, then the system passes the adequate airflow
criterion.
b) If the difference is between minus 4°F and minus 100°F, then the measurement procedure shall be
repeated making sure that temperatures are measured in a manner that obtains the average
temperature in the airflow.
c) If the re-measured difference is between plus 4°F and minus 4°F the system passes the adequate
airflow criteria. If the re-measured difference is between minus 4°F and minus 100°F, the system
passes, but it is likely that the capacity is low on this system (it is possible, but unlikely, that airflow is
higher than average).
RA3.2.3 Alternate Charge Measurement Procedure
This
section specifies the alternate charge measurement procedure. Under this procedure, the required
refrigerant charge is calculated using the Weigh-In Charging Method.
HVAC installers who must complete system installation verification when the outdoor temperature is below
55°F shall use this alternate procedure in conjunction with installing and charging the system in accordance
with the manufacturer’s specifications. HERS Raters shall not use this procedure to verify compliance. Split
system air conditioners come from the factory already charged with the standard charge indicated on the
nameplate. The manufacturer supplies the charge proper for the application based on their standard liquid line
length. 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 lengths different from the manufacturer's standard.