Specifications

2008 Residential Appendices RA3-22
Appendix RA3 – Residential Field Verification and Diagnostic Test Protocols
The apparatus for measuring the system fan flow shall consist of a duct pressurization and flow
measurement device (subsequently referred to as a fan flowmeter) meeting the specifications in RA3.3.1,
a static pressure transducer meeting the specifications in Section RA3.3.1, The measuring device shall
be attached at the air handler blower compartment door, or alternatively at the inlet to a return from the
conditioned space. The measuring device shall be attached at a point where all the fan airflow shall flow
through it. When the air handler blower compartment door is used an air barrier must be placed between
the return duct system and the air handler inlet(s). All registers shall be in their normal operating
condition. The static pressure probe shall be fixed to the supply plenum at the location specified in
Section RA3.3.1.1 so that it is not moved during this test.
RA3.3.2.1.2 Flow Cap
ture Hood Measurement
A flow capture hood meeting the specifications in Section RA3.3.1 may be used to verify the fan flow at
the return register(s) if the device has a capture area at least as large as the returns in all dimensions. All
registers shall be in their normal operating position. Measurement(s) shall be taken at the return grill(s).
RA3.3.2.1.3 Flow Grid Measur
ement
The apparatus for measuring the system fan flow shall consist of a flow measurement device
(subsequently referred to as a fan flow grid) meeting the specifications in RA3.3.1 and a static pressure
transducer meeting the specifications in Section RA3.3.1. The measuring device shall be attached at a
point where all the fan airflow shall flow through the flow grid. All registers shall be in their normal
operating condition. The static pressure probe shall be fixed to the supply plenum at the location specified
in Section RA3.3.1.1 so that it is not moved during this test.
RA3.3.2.2 Air Handler Watts
The air h
andler watt draw shall be measured using one of the following methods.
RA3.3.2.2.1 Portable
Watt Meter Measurement
The apparatus for measuring the air handler watt draw shall consist of a wattmeter meeting the
specifications in RA3.3.1. The measuring device shall be attached to measure the air handler fan watt
draw. All registers and blower access panel(s) shall be in their normal operating condition.
RA3.3.2.2.2 Utility Reven
ue Meter Measurement
The apparatus for measuring the air handler watt draw shall consist of the utility revenue meter meeting
the specifications in RA3.3.1 and a stopwatch measuring in seconds. All registers and blower access
panel(s) shall be in their normal operating condition.
RA3.3.3 Procedure
This p
rocedure determines the cooling coil airflow, fan Watts, and duct design compliance.
To determine and verify airflow and fan watt draw credit, in addition to verifying airflow, the air handler fan
watt draw measurement shall show fan watts less than that claimed in compliance software calculations
and shown on the CF-1R.
RA3.3.3.1 Diagnostic Fan Flow
For complia
nce calculations using verified prescriptive cooling coil airflow, or for compliance calculations
using target values for verified cooling coil airflow that exceed prescriptive airflow, the installed system
shall be diagnostically tested using one of the methods specified in this section.
For multi-zone systems the airflow must be measured for each and every operating mode of the system.
This must be accomplished without bypasses from the supply ductwork to the return ductwork. Note: All
airflows are for the fan set at the speed used for air conditioning.
The system passes the Diagnostic Fan Flow test if the measured cooling coil airflow is equal to or greater
than the value claimed in compliance calculations and reported by the ACM on the CF-1R.