AHRI 420 (I-P) and 421 (SI): Performance Rating of Forced-Circulation Free-Delivery Unit Coolers for Refrigeration

This standard applies to factory-made, forced-circulation free-delivery unit coolers, as defined in Section 3, operating with a volatile refrigerant fed by either direct expansion or liquid overfeed at wet or dry conditions, or both.

Exclusions

This standard does not apply to:

1. Air-conditioning units used primarily for comfort cooling where testing methods are given in other standards


2. Unit coolers operating at latent load conditions with refrigerant saturation temperature 32°F to prevent frost


3. Unit coolers installed in or connected to ductwork


4. Unit coolers using zeotropic refrigerants with glides greater than 2.0°F


5. Field testing of unit coolers

AHRI 420-2023 (I-P): Performance Rating of Forced-Circulation Free-Delivery Unit Coolers for Refrigeration 

AHRI 421-2023 (SI): Performance Rating of Forced-Circulation Free-Delivery Unit Coolers for Refrigeration

AHRI 420-2016 (I-P): Performance Rating of Forced-Circulation Free-Delivery Unit Coolers for Refrigeration

AHRI 421-2016 (SI): Performance Rating of Forced-Circulation Free-Delivery Unit Coolers for Refrigeration

© 2023, by Air-Conditioning, Heating, and Refrigeration Institute