For SI: | 1 British thermal unit per hour = 0.2931 W. | ||
Ec | = | Combustion efficiency (100 percent less flue losses). | |
Et | = | Thermal efficiency. See referenced standard document for detailed information. | |
a | These requirements apply to boilers with rated input of 8,000,000 Btu/h or less that are not packaged boilers and to all packaged boilers. Minimum efficiency requirements for boilers cover all capacities of packaged boilers. | ||
b | Maximum capacity minimum and maximum ratings as provided for and allowed by the unit's controls. | ||
c | Includes oil-fired (residual). |
Equipment Typea | Subcategory or Rating Condition | Size Category (Input) | Minimum Efficiency | Test Procedure |
Boilers, hot water | Gas-fired | < 300,000 Btu/hd,e | 82% AFUE | 10 C.F.R. Part 430 |
≥ 300,000 Btu/h and ≤ 2,500,000 Btu/hb | 80% Et | 10 C.F.R. Part 431 | ||
˃ 2,500,000 Btu/ha | 82% Ec | |||
Oil-firedc | < 300,000 Btu/he | 84% AFUE | 10 C.F.R. Part 430 | |
≥ 300,000 Btu/h and ≤ 2,500,000 Btu/hb | 82% Et | 10 C.F.R. Part 431 | ||
˃ 2,500,000 Btu/ha | 84% Ec | |||
Boilers, steam | Gas-fired | < 300,000 Btu/hd | 80% AFUE | 10 C.F.R. Part 430 |
Gas-fired - All, except natural draft | ≥ 300,000 Btu/h and ≤ 2,500,000 Btu/hb | 79% Et | 10 C.F.R. Part 431 | |
˃ 2,500,000 Btu/ha | 79% Et | |||
Gas-fired-natural draft | ≥ 300,000 Btu/h and ≤ 2,500,000 Btu/hb | 79% Et | ||
˃ 2,500,000 Btu/ha | 79% Et | |||
Oil-firedc | < 300,000 Btu/h | 82% AFUE | 10 C.F.R. Part 430 | |
≥ 300,000 Btu/h and ≤ 2,500,000 Btu/hb | 81% Et | 10 C.F.R. Part 431 | ||
˃ 2,500,000 Btu/ha | 81% Et |
For SI: | 1 British thermal unit per hour = 0.2931 W. | ||
Ec | = | Combustion efficiency (100 percent less flue losses). | |
Et | = | Thermal efficiency. See referenced standard document for detailed information. | |
a | These requirements apply to boilers with rated input of 8,000,000 Btu/h or less that are not packaged boilers and to all packaged boilers. Minimum efficiency requirements for boilers cover all capacities of packaged boilers. | ||
b | Maximum capacity minimum and maximum ratings as provided for and allowed by the unit's controls. | ||
c | Includes oil-fired (residual). | ||
d | Boilers shall not be equipped with a constant burning ignition pilot. | ||
e | A boiler not equipped with a tankless domestic water heating coil shall be equipped with an automatic means for adjusting the temperature of the water such that an incremental change in inferred heat load produces a corresponding incremental change in the temperature of the water supplied. |