scope:

This standard provides test procedures for determining the efficiency and hot-water delivery capability of the water heating equipment to which it applies.

This standard applies to electric resistance, heat-pump, natural- and propane-gas-fired, and oil-fired water heating equipment, including hot-water supply boilers, with input ratings less than 12,500,000 Btu/h (3660 kW) that are described by one or more of the following:

a. Gas-fired water heaters with a self-contained, temperature-activated primary operating control and not requiring circulation of water for heating, with rated input greater than 105,000 Btu/h (30.8 kW).

b. Oil-fired water heaters with a self-contained, temperature-activated primary operating control and not requiring circulation of water for heating, with rated input greater than 140,000 Btu/h (41 kW).

c. Electric resistance water heaters with a primary self-contained, temperature-activated operating control and not requiring circulation of water for heating, with rated input greater than 12 kW.

d. Gas-fired water heaters with a self-contained, flow-activated primary operating control and requiring water flow for heating, with rated input greater than 200,000 Btu/h (58.6 kW). Flow sensing may be based on physical flow measurement or interpretation of a temperature measurement as flow.

e. Oil-fired water heaters with a self-contained, flow-activated primary operating control and requiring water flow for heating, with rated input greater than 210,000 Btu/h (61.5 kW). Flow sensing may be based on physical flow measurement or interpretation of a temperature measurement as flow.

f. Electric resistance water heaters with a self-contained, flow-activated primary control and requiring water flow for heating, with rated input greater than 58.6 kW.

g. Gas-fired water heaters with a remote temperature-activated primary operating control and requiring circulation through the heater for heating, with rated input greater than 105,000 Btu/h (30.8 kW).

h. Oil-fired water heaters with a remote temperature-activated primary operating control and requiring circulation of water through the heater for heating, with rated input greater than 140,000 Btu/h (41 kW).

i. Electric resistance water heaters with a remote temperature-activated operating control and requiring circulation through the heater for heating, with rated input greater than 12 kW.

j. Air-source, water-source, and direct geoexchange heat-pump water heaters, with rated input greater than 12 kW for electric vapor-compression heat pumps, or with rated input greater than 20,000 Btu/h (5.9 kW) for gas-fired heat pumps.

k. Water heaters designed to deliver water at a controlled temperature greater than 180°F (82°C).

l. Water heaters with three-phase electrical supply.

m. Water heaters with rated storage capacity greater than 120 gal (454 L).

n. Gas-fired or oil-fired hot-water supply boilers with rated input equal to or greater than 300,000 Btu/h (87.9kW).

PURPOSE

The purpose of this standard is to provide test procedures for rating directly heated commercial service water heating equipment.