1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 731 Oil-Fired Unit HeatersUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODU
2、CTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Oil-Fired Unit Heaters, UL 731 Fifth Edition, Dated September 25, 1995 Summary of Topics This revision to UL 731 is being issued to remove the reference to the withdrawal date of UL 873 and to address universal upkeep of UL
3、Standards for Safety. These revisions are considered to be non-substantive and not subject to ULs STP process. Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. Changes in requirements are marked with a vertical lin
4、e in the margin and are followed by an effective date note indicating the date of publication or the date on which the changed requirement becomes effective. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form by any means, ele
5、ctronic, mechanical photocopying, recording, or otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expressed or implied, including but not limited to, the implied warranties of merchantability or tness for any purpose. In no event will UL b
6、e liable for any special, incidental, consequential, indirect or similar damages, including loss of prots, lost savings, loss of data, or any other damages arising out of the use of or the inability to use this Standard, even if UL or an authorized UL representative has been advised of the possibili
7、ty of such damage. In no event shall ULs liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the electronic versions of ULs Standards for Safety agree to defend, indemnify, and hold UL harmless from and against any loss, expense, liabi
8、lity, damage, claim, or judgment (including reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic Standard on the purchasers computer system. The requirements in this Standard are now in effect, except for those paragraphs, sections, tab
9、les, gures, and/or other elements of the Standard having future effective dates as indicated in the note following the affected item. The prior text for requirements that have been revised and that have a future effective date are located after the Standard, and are preceded by a SUPERSEDED REQUIREM
10、ENTS notice. OCTOBER 9, 2013 UL 731 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL OCTOBER 9, 2013 UL 731 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL
11、SEPTEMBER 25, 1995 (Title Page Reprinted: October 9, 2013) 1 UL 731 Standard for Oil-Fired Unit Heaters First Edition August, 1955 Second Edition April, 1974 Third Edition May, 1975 Fourth Edition March, 1988 Fifth Edition September 25, 1995 This ANSI/UL Standard for Safety consists of the Second Ed
12、ition including revisions through October 9, 2013. The most recent designation of ANSI/UL 731 as a Reaffirmed American National Standard (ANS) occurred on August 22, 2012. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, Title Page, or effective date information. Comm
13、ents or proposals for revisions on any part of the Standard may be submitted to UL at any time. Proposals should be submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor elect
14、ronic copy of a Standard should be altered in any way. All of ULs Standards and all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2013 UNDERWRITERS LABORATORIES INC. UL/ANSI 731-2004 (R2012)UL COPYRIGHTED MATERIAL NOT AUTHO
15、RIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 14, 2004 OIL-FIRED UNIT HEATERS - UL 731 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .5 2 Glossary .5 3 Com
16、ponents 9 CONSTRUCTION 4 Assembly .10 5 Burners .11 6 Accessibility for Servicing .11 7 Disposal of Combustion Products 11 8 Base .11 9 Casing 11 10 Radiation Shields and Materials in Air-Handling Compartments .12 11 Air Filter .12 12 Combustion Chamber .13 13 Radiator .13 14 Heating Surface Joints
17、13 15 Baffles.14 16 Flue Collar .14 17 Damper and Draft Regulator .14 18 Controls .14 18.1 Application 14 18.2 Limit control .15 19 Field Wiring 15 19.1 General .15 19.2 Leads and terminals 17 20 Internal Wiring 19 20.1 General .19 20.2 Methods 19 20.3 Short circuit protection 22 21 Separation of Ci
18、rcuits .22 22 Bonding for Grounding 23 23 Electrical Components General .26 24 Mounting of Electrical Components .26 25 Electrical Enclosures 27 25.1 General .27 25.2 Doors and covers .32A 25.3 Field wiring system connection .33 26 Motors and Motor Overload Protection 34 27 Overcurrent Protection of
19、 High-Voltage Control-Circuit Conductors 38 27.1 General .38 27.2 Direct-connected high-voltage control circuit .38 27.3 Tapped high-voltage control circuits 38 27.4 Overcurrent-protective devices .39 28 Overcurrent Protection of Transformers 40 28.1 High-voltage transformers .40 28.2 Low-voltage tr
20、ansformers 41 28.3 Overcurrent protective devices .41 MAY 14, 2004 OIL-FIRED UNIT HEATERS - UL 731 2AUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 29 Switches and Controllers 42 30 Capacitors .43 31 Electrical Insulating Material 43 32 Hig
21、h-Voltage Circuits Spacings .43 33 Low-Voltage Circuits Spacings .45 PROTECTION OF USERS AND SERVICE PERSONNEL 34 General 45 PERFORMANCE 35 General 48 36 Test Installation Floor-Mounted Heaters .49 36.1 Enclosure .49 36.2 Chimney connector .50A 36.3 Air outlet and inlet 52 37 Test Installation Suspe
22、nded Type Heaters .53 37.1 Enclosure .53 37.2 Chimney connector .53 37.3 Air outlet and inlet 55 38 Instrumentation .55 38.1 Draft 55 38.2 Fuel input .55 38.3 Power measurement 55 38.4 Speed measurement .56 38.5 Temperature measurement 56 39 Initial Test Conditions .58 39.1 General .58 39.2 Heater e
23、quipped with mechanical atomizing burner .58A 40 Combustion Test Burner and Heater .58A 41 Continuous Operation Tests 58B 42 Limit Control Cutout Test .58B 43 Continuity of Operation Test .59 44 Temperature Test .59 45 Continuous Operation Temperatures 60 46 Fan Failure Test 64 47 Stalled Fan Motor
24、Test 65 48 Blocked Inlet Test .65 49 Short Circuit Test .65 50 Overload Test, High-Voltage Transformers .68 51 Burnout Test, High-Voltage Transformers 68 52 Dielectric Voltage-Withstand Test .69 MANUFACTURING AND PRODUCTION TESTS 53 General 70 MARKING 54 General 71 APRIL 22, 2010 OIL-FIRED UNIT HEAT
25、ERS - UL 731 2BUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INSTALLATION INSTRUCTIONS 55 General 73 APPENDIX A Standards for ComponentsA1 MAY 14, 2004 OIL-FIRED UNIT HEATERS - UL 731 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REP
26、RODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL This page intentionally left blank. MAY 14, 2004 OIL-FIRED UNIT HEATERS - UL 731 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements apply to oil-r
27、ed unit heaters as dened herein. Unit heaters designed to supply heated air through ducts are covered in the Standard for Oil-Fired Central Furnaces, UL 727. 1.2 Requirements for the installation and use of oil-burning equipment are included in the Standard for the Installation of Oil Burning Equipm
28、ent, NFPA 31 and the BOCA National Mechanical Code. 1.3 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of re or of electric shock or injury to persons shall be eva
29、luated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conict with specic requirements or provisions of this stan
30、dard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard. 1.4 If a value for measurement is followed by a value in other units in parentheses, the second val
31、ue may be only approximate. The rst stated value is the requirement. 2 Glossary 2.1 For the purpose of this standard, the following denitions apply. 2.2 AIR SHUTTER An adjustable device for varying the size of the air inlet or inlets regulating primary or secondary air. 2.3 ANTIFLOODING DEVICE A pri
32、mary safety control which causes the fuel ow to be shut off upon a rise in fuel level or upon receiving excess fuel, and which operates before the hazardous discharge of fuel can occur. 2.4 APPLIANCE FLUE The ue passages within the appliance. 2.5 AUTOMATICALLY LIGHTED APPLIANCE An appliance in which
33、 fuel to the main burner is normally turned on and ignited automatically. 2.6 BAFFLE An object placed in an appliance to direct the ow of air or ue gases. 2.7 BASE The main supporting frame or structure of the furnace, exclusive of legs. 2.8 BURNER A device for the nal conveyance of fuel or a mixtur
34、e of fuel and air to the combustion zone. 2.9 BURNER, AUTOMATICALLY LIGHTED One where fuel to the main burner is normally turned on and ignited automatically. 2.10 BURNER, MANUALLY LIGHTED One where fuel to the main burner is turned on only by hand and ignited under supervision. MAY 14, 2004 OIL-FIR
35、ED UNIT HEATERS - UL 731 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2.11 BURNER, MECHANICAL-ATOMIZING TYPE A power-operated burner which prepares and delivers the oil and all or part of the air by mechanical process in controllable qua
36、ntities for combustion. Some examples are air atomizing, high and low pressure atomizing, horizontal rotary, vertical rotary atomizing, and vertical rotary wall-ame burners. 2.12 BURNER, MECHANICAL DRAFT TYPE A burner which includes a power-driven fan, blower, or other mechanism as the principal mea
37、ns for supplying air for combustion. 2.13 BURNER, NATURAL DRAFT TYPE A burner which depends principally upon the natural draft created in the ue to induce into the burner the air required for combustion. 2.14 BURNER, VAPORIZING TYPE A burner consisting of an oil-vaporizing bowl or other receptacle t
38、o which liquid fuel may be fed in controllable quantities. The heat of combustion is used to vaporize the fuel, with provision for admitting air and mixing it with the oil vapor in combustible proportions. 2.15 CASING An enclosure forming the outside of the appliance, no parts of which are likely to
39、 be subjected to intense heat. 2.16 CENTRAL HEATING APPLIANCE A stationary indirect-red vented appliance comprising the following classes: boilers, central furnaces, oor furnaces, and recessed heaters. A oor-mounted unit heater to be connected to a duct system is classied also as a central heating a
40、ppliance. 2.17 CHIMNEY CONNECTOR The pipe which connects a solid or liquid fuel burning appliance to a chimney. 2.18 COMBUSTIBLE MATERIAL Combustible material as pertaining to materials adjacent to or in contact with heat-producing appliances, chimney connectors, vent connectors, and warm air ducts
41、means material made of or surfaced with wood, compressed paper, plant bers, or other material that will ignite and burn. Such material shall be considered as combustible even though ameproofed, re retardant treated, or plastered. 2.19 COMBUSTION As used herein, the rapid oxidation of fuel accompanie
42、d by the production of heat, or heat and light. Complete combustion of a fuel is possible only in the presence of an adequate supply of oxygen. 2.20 COMBUSTION CHAMBER The portion of an appliance within which combustion occurs. 2.21 COMBUSTION (FLAME) SAFEGUARD A safety combustion control. 2.22 CONS
43、TANT-LEVEL VALVE A device for maintaining within a reservoir a constant level of fuel for delivery to the burner. 2.23 CONTROL A device designed to regulate the fuel, air, water, or electrical supply to the controlled equipment. It may be automatic, semiautomatic, or manual. 2.24 CONTROL, LIMIT An a
44、utomatic safety control responsive to changes in liquid level, pressure, or temperature used for limiting the operation of the controlled equipment. 2.25 CONTROL, SAFETY Automatic controls (including relays, switches, and other auxiliary equipment used in conjunction therewith to form a safety contr
45、ol system) which are intended to prevent unsafe operation of the controlled equipment. SEPTEMBER 25, 1995 OIL-FIRED UNIT HEATERS - UL 731 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2.26 CONTROL, PRIMARY SAFETY The automatic safety cont
46、rol intended to prevent abnormal discharge of oil at the burner in case of ignition failure or ame failure. 2.27 CONTROL, SAFETY COMBUSTION A primary safety control responsive directly to ame properties. It senses the presence of ame and causes fuel to be shut off in event of ame failure. 2.28 DAMPE
47、R A valve or plate for regulating draft or ow of ue gases. A damper is generally considered as being located on the downstream side of the combustion chamber, usually in a ue passage of the appliance or in the chimney connector. 2.29 DAMPER, AUTOMATICALLY OPERATED A damper operated by an automatic c
48、ontrol. 2.30 DAMPER, MANUALLY OPERATED An adjustable damper manually set and locked in the desired position. 2.31 DRAFT REGULATOR A device which functions to maintain a desired draft in the appliance by automatically reducing the chimney draft to the desired value. 2.32 ELECTRICAL CIRCUITS: a) High-
49、Voltage Circuit A circuit involving a potential of not more than 600 volts and having circuit characteristics in excess of those of a low-voltage circuit. b) Low-Voltage Circuit A circuit involving a potential of not more than 30 volts alternating-current (42.4 peak or direct current) and supplied by a primary battery, a standard Class 2 transformer or other suitable transforming device, or a suitable combination of transforme
