CSA ANSI Z21.10.3A-2000/4.3A-M00

Scope This standard applies to newly produced, large automatic storage water heaters having input ratings above 75,000 Btu per hour (21 980 W), instantaneous water heaters and circulating water heaters for use with natural gas, manufactured gas, mixed gas, liquefied petroleum gases and LP gas-air mixtures; for recreational vehicle installation for use with liquefied petroleum gases only; for manufactured home (mobile home) installation convertible for use with natural gas and liquefied petroleum gases when provision is made for the simple conversion from one gas to the other; and for recreational vehicle installation convertible for use with natural gas and liquefied petroleum gases when provision is made for the simple conversion from one gas to the other. The requirements also apply to automatic storage type water heaters for use with combination potable water/space heating applications. Direct vent water heate rs covered by this standard are essentially balanced flue appliances with the air intake and vent outlet in close proximity. Water heaters for installation in recreational vehicles shall be of the direct vent type. This standard also applies to water heaters with draft hoods which are factory equipped with automatic vent damper devices. This standard also applies to water heaters of other than the direct vent type which are factory equipped with electrically operated or m echanically actuated automatic flue damper devices.