UL 834

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These requirements cover electric heating, water supply, and power boilers rated at 600 volts or less intended for commercial or industrial applications utilizing hot water or steam. They may also be used for commercial , industrial, or residential use space heating applications.

These boilers a re intended for installation in accordance with the National Electrical Code, NFPA 70-1993, and other applicab le codes, such as the BOCA National Mechanical Code, the Standard Mechanical Code, and th e Uniform Mechanical Code.

Each boiler consists of sheath ed resistance-type heating elements and a vessel or tank constructed, inspected, and stamped in accordance with the applicable sections of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. Each boiler is provided with one or more safety valves or safety relief valve s conforming to ASME requirements with all necessary temperature or pressure regulating controls, including a n integral limit control, wiring, and auxiliary equipment assembled as a unit.

These requirements do not cover water supply boilers and hot water and steam generating equipment employing constructions which are outside the scope of, or not covered by, the ASME codes, nor commercial cooking or medical and dental eq uipment, nor other electric heating equipment or appliances which are covered in, or as part of , separate, individual requirements. Electrode-type boilers also are not covered by these requirements.

The equipment covered by this standard shall be one of the following types of water heating boilers:

a) High Pressure – A boiler furnishing:

—1) Steam at pressures in excess of 15 psig (103 kPa); or

—2) Hot water at temperatures in excess of 250 F (121 C) or at pressures in excess of 160 psi g (1100 kPa).