Historical
ANSI Z21.56-2006/CSA 4.7-2006
Gas-Fired Pool Heaters
This standard applies to newly produced pool heaters (see Part IV, Definitions), hereinafter referred to as pool heaters or appliances, constructed entirely of new, unused parts and materials, for heating nonpotable water stored at atmospheric pressure, such as water in swimming pools, spas, hot tubs and similar applications: a. For use with natural gas; b. For use with manufactured gas; c. For use with mixed gas; d. For use with liquefied petroleum gases; and e. For use with LP gas-air mixtures.
CSA America, Inc. [csa]