USE OM - JANUARY 2017
67
APPENDIX I: SECONDARY CAPACITY CHECK REQUIREMENTS
Section 1. Purpose
The purpose of this appendix is to specify the requirements for secondary capacity checks that any independent third party
laboratory must comply with during AHRI USE Certification Program testing.
Section 2. Scope
2.1
The requirements of this appendix shall apply to all USE Certification Program testing of:
2.1.1
Unitary Small Air-Conditioners (Systems and Mixed-Match Coils) which are Air-Cooled
2.1.2
Unitary Small Air-Source Heat Pumps (Systems and Mixed-Match Coils) which are Air-Cooled
2.2
The requirements of this appendix are not applicable to:
2.2.1
Unitary Small Air-Conditioners (Systems and Mixed-Match Coils) which are Evaporatively or Water-
Cooled.
Section 3. Definitions
3.1
Code Tester.
A nozzle airflow measuring apparatus as defined by ASHRAE Standard 37 Section 6.2.
3.2
Flow Meter Assembly.
A mass flow meter, associated tubing, associated valve assemblies, sight glasses and any
other associated components that add internal volume to the operating system.
3.3
Pressure Transducer Assembly.
A pressure transducer, associated tubing, associated valve assemblies, and any
other associated components that add internal volume to the operating system.
Section 4. Symbols
4.1
q
tia
= total capacity, indoor, air, Btu/h
4.2
q
tir
= total capacity, indoor, refrigerant, Btu/h
4.3
q
toa
= total capacity, outdoor, air, Btu/h
4.4
For coil-only applications, total capacity as defined in 4.1, 4.2 and 4.3 shall be defined as gross capacities.
4.5
For applications having a blower motor, total capacity as defined in 4.1, 4.2 and 4.3 shall be defined as net
capacities.
4.6
HB = heat balance =
(𝑞𝑡𝑖𝑎−𝑞𝑡𝑖𝑟)
𝑞𝑡𝑖𝑎
or =
(𝑞𝑡𝑖𝑎−𝑞𝑡𝑜𝑎)
𝑞𝑡𝑖𝑎
