ComfortStar mentions the following reasons for approving R421A as the only acceptable R22 alternative refrigerant for use in their equipment-
-R421A is an environmentally friendly non ozone depleting replacement for R22
-R421A can replace R22 without modification-
-R421A no hydrocarbons such as butane, and is rated “A1” by ASHRAE
-R421A is non flammable and rated A1 by ASHRAE
-R421A can be used with Mineral, AB, or POE oils*
-R421A is comparable to R22 in terms of performance and pressures, approximately 1% higher at 95°F
For more information on Choice R421A, please visit our website or contact us toll-free at 1-855-GET-421A.
*If there is a vertical height difference of 20 feet or more between the evaporator and condensor, the system must be converted to POE.