This Standard applies to newly produced, automatic storage water
heaters having input ratings of 75,000 Btu/hr (21 980 W) or less
(see Clause 3, Definitions), hereinafter referred to as water
heaters or appliances, constructed entirely of new, unused parts
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;
e) for use with LP gas-air mixtures;
f) for recreational vehicle installation for use with liquefied
petroleum gases only (see Clause 4.1.26);
g) 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 (see Clause 4.1.25);
h) 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 (see
Clause 4.1.26); and
i) for use with combination potable water/space heating
applications (see Clause 4.1.29 and Clause 3, Definitions).
This Standard also applies to water heaters incorporating heat
pipe heat exchangers (see Clause 4.4, Heat pipe heat
Direct vent water heaters anticipated by this Standard are
essentially balanced flue appliances with the air intake and vent
outlet in close proximity. Other designs are to be subjected to
such additional tests as believed necessary at the discretion of
the testing agency.
Water heaters for installation in recreational vehicles are to
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 (see
Clause 3, Definitions), hereinafter referred to as vent damper
This Standard also applies to water heaters of other than the
direct vent type which are factoryequipped with electrically
operated or mechanically actuated automatic flue damper devices
(see Clause 3, Definitions), hereinafter referred to as flue damper
If a value for measurement as given in this Standard is followed
by an equivalent value in other units, the first stated value is to
be regarded as the specification, except as noted in Clauses 4.33.1
All references to "psi" throughout this Standard are to be
considered gauge pressures unless otherwise specified.
Clause 7, Items unique to the United States, contains provisions
that are unique to the United States.
Clause 8, Items unique to Canada, contains provisions that are
unique to Canada.
Special construction provisions applicable to a water heater
designed for use with an optional listed conversion kit are
outlined under Annex F, Optional provisions for listed appliance
Clause 2, Reference publications, contains a list of standards
specifically referenced in this Standard, and sources from which
these reference standards may be obtained.
Order online or call: Americas: +1 800 854 7179 | Asia Pacific: +852 2368 5733 | Europe, Middle East, Africa: +44 1344 328039