UL 834
Standard for Heating, Water Supply, and Power Boilers - Electric

DETAILS
Edition Number:5SCC Approved:--
Edition Date:2004-04-13DOD Approved: --
Price Code:AANSI Approved: 2019-07-11
Type:ulstd

  • SCOPE

    1 Scope

    1.1 These requirements cover electric heating, water supply, and power boilers rated at 15,000 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.

    1.2 The boilers covered by these requirements are intended for installation in accordance with the National Electrical Code, NFPA 70 , the International Mechanical Code, and the Uniform Mechanical Code.

    1.3 Each boiler consists of sheathed 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 valves conforming to ASME requirements with all necessary temperature or pressure regulating controls, including an integral limit control, wiring, and auxiliary equipment assembled as a unit.

    1.4 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 equipment, 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.

    1.5 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 psi (103 kPa); or

    2)    Hot water at temperatures in excess of 250°F (121°C) or at pressures in excess of 160 psi (1103 kPa).

    b)    Low-Pressure Hot-Water and Low-Pressure Steam – A boiler furnishing:

    1)    Hot water at pressures not exceeding 160 psi and at temperatures not more than 250°F; or

    2)    A boiler furnishing steam at pressures not more than 15 psi.

    c)    Miniature – A boiler that does not exceed the following limits:

    1)    16 inches (406 mm) inside diameter of shell; and

    2)    5 cubic feet (0.14 m3) gross volume, exclusive of casing and insulation, and 100 psi (690 kPa) maximum allowable working pressure.

    For the applicable ASME Code symbol, see Section 5.

  • TABLE OF CONTENTS
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    • Cover
    • Transmittal
    • Table of Contents
      • Body
        • INTRODUCTION
          • 1 Scope
          • 2 Components
          • 3 Units of Measurement
          • 4 Undated References
          • 5 Special Designations
          • 6 Glossary
        • CONSTRUCTION
          • 7 Frame and Enclosure
            • 7.1 General
            • 7.2 Doors and covers
            • 7.3 Enclosure thickness
            • 7.4 Live parts
          • 8 Protection of Service Personnel
          • 9 Mechanical Assembly
          • 10 Corrosion Protection
          • 11 Electrical Supply Connections of Permanently Connected Boilers
          • 12 Field Wiring System Connections
          • 13 Provisions For Connections To Busway
          • 14 Field Wiring Terminals and Leads
          • 15 Cord-Connected Boilers
          • 16 Wiring Space
          • 17 Stability
          • 18 Current-Carrying Parts
          • 19 Internal Wiring
            • 19.1 General
            • 19.2 Methods
          • 20 Splices
          • 21 Separation of Circuits
          • 22 Barriers
          • 23 Heating Elements
          • 24 Electrical Insulation
          • 25 Thermal Insulation
          • 26 Motors
          • 27 Overcurrent Protection
            • 27.1 Heating element circuits
            • 27.2 Internal conductors
            • 27.3 Motors
            • 27.4 Receptacles and lamps
            • 27.5 Control circuits
            • 27.6 Direct-connected high-voltage control circuit
            • 27.7 Tapped high-voltage control circuits
          • 28 Transformer Overcurrent Protection
            • 28.1 High-voltage transformer
            • 28.2 Low-voltage transformers
          • 29 Lampholders
          • 30 Switches
          • 31 Limit Controls
          • 32 Low-Water Cutoff
          • 33 Terminals and Sensing Elements of Operating and Limit Controls
          • 34 Pressure-Relieving Devices
          • 35 Spacings
          • 36 Grounding
        • PERFORMANCE
          • 37 General
          • 38 Test Installation for Alcove or Closet
          • 39 Leakage Current Test
          • 40 Power Input Test
          • 41 Limit Control Cutout Test
          • 42 Temperature Test
          • 43 Continuous Operation Test
            • 43.1 General
            • 43.2 Hot water boiler
            • 43.3 Steam boiler
          • 44 Pump-Failure Test
          • 45 Blocked-Flow Test
          • 46 Dielectric Voltage-Withstand Test
          • 47 Insulation Resistance Test
          • 48 Overload Tests
          • 49 Low Water Abnormal Test
          • 50 Short Circuit Test
          • 51 Burnout Test – High-Voltage Transformer
          • 52 Overload Test – High-Voltage Transformer
          • 53 Push-Back Relief Test
        • MANUFACTURING AND PRODUCTION TESTS
          • 54 Production-Line Dielectric Voltage-Withstand Test
          • 55 Production-Line Grounding-Continuity Test
        • RATING
          • 56 Details
        • MARKING
          • 57 Details
        • INSTRUCTIONS
          • 58 Details
    • APPENDIX A