SUN - UL 2021, Fixed and Location Dedicated Electric Room Heaters

A cord-connected heater shall be provided with a pilot light having a non-user-replacable lamp (e.g. LED) or lens that glows red or amber. The light shall:

1. Be located on the front or top surface of the heater;
2. Protrude from the top surface of the heater if so located; and
3. Comply with 13.6.2. The pilot light shall be connected to the heater circuit so that it is energized whenever the on-off switch (see 28.11) is in the on position. Compliance of the pilot light shall be determined in all operating modes when the on-off switch is in the on position.

Exception No. 1: A pilot light is not required if a visibly glowing heating element of a radiant heater can be considered to serve as an indicator that the heater is energized. A heating element is considered to serve as an indicator if:

1. The heating element for the heater consists of a single element,
2. The element is not cycled by an automatic control,
3. The element cannot be operated by either a manual or automatic control, at a reduced rating so that it can no longer be considered a visibly glowing element in accordance with 59.25, and
4. The heater complies with the visibility requirement of 13.6.2.

Exception No. 2: A pilot light is not required on a commercial/industrial heater.

Exception No. 3: A pilot light is not required on a hearth type heater having a flame effect feature. The flame effect feature shall have a majority red or amber color, be illuminated by at least two lamps and shall comply with the visibility requirement of 13.6.2. The flame effect feature shall be connected to the heater circuit so that it is energized whenever the on-off switch (see 28.11) is in the on position. Compliance of the flame effect feature shall be determined in all operating modes when the on-off switch is in the on position.

With respect to the conditions for Operation Tests, Section 37, and Abnormal Operation Tests, Section 41, if operation of the heater in accordance with 37.1 could result in a risk of fire or electric shock due to overheating of the heater, a thermal cutoff or a manual reset type temperature limit control shall be provided. If a manual reset type limiting control is provided, it shall be of a type that will not operate as an automatic reset control when the reset means is held in the reset position.

Exception: An automatic reset type temperature limiting control or a manual reset type limiting control that operates as an automatic reset type when the reset means or actuating member is held in the reset position may be used as a control to limit temperatures for the heaters specified in (a) – (e) below.

1. a) For a fixed heater that is ceiling mounted or is marked as stated in 59.23.
2. b) For a heater in which the manual reset temperature limiting control reset means or actuating member is arranged such that it:
   1. Is recessed within the overall appliance enclosure,
   2. Cannot be forced to remain in the reset position by likely methods, such as taping down a pushbutton or wedging a pushbutton in an opening through which it protrudes, and
   3. Is not jammed in the reset position during the Element Support Impact Tests, Section 51, or
3. c) For a commercial/industrial heater.
4. d) For a heater that complies with the following additional requirements:
   1. The cycling frequency for the temperature limiting control shall be monitored and recorded for each abnormal test in which the temperature limiting control operates. The average cycle rate after each test shall be determined and shall not exceed 12 cycles per hour (at least 5 minutes per cycle).
   2. During each abnormal test where combustibles are placed in contact with or very near the heater (Vertical Wall, Terry Cloth Drape, and Padded Surface), the temperature of the test material shall be measured and recorded in locations believed to represent the areas receiving the most heat from the heater such as at the discharge grill. The maximum temperatures shall not exceed 200 °C (392 °F) except during the first five cycles where the maximum shall not exceed 225 °C (437 °F).
5. e) For floor-insert heaters (see 32.3).

A heater intended for residential use that is provided with an over-temperature limit control shall include an audible or visual alarm to indicate that the limit control has operated. See 25.2 and 25.3. The alarm shall become energized when the limit control functions to de-energize the heating elements. For an automatically-resetting temperature limiting control, when the temperature limiting control reconnects electric power to the heating element (s), the alarm may be de-energized or it may remain energized until de-energized manually. For a manual-reset temperature limiting control that operates as an automatic reset type when the reset means is held, the alarm shall remain energized until the temperature limiting control is reset.

Exception: Heaters that use the following types of temperature limit controls:

1. Manual reset type temperature limit control that will not operate as automatic reset type control when the reset means is held in the reset position. See 24.1; or
2. Thermal cutoff.

Installation

60.2.1 Clear and complete instructions for the installation of the heater shall be provided. The instructions shall include the following items:

1. Wiring procedures and connections shall be in accordance with the national and local codes having jurisdiction.
2. A complete electrical diagram of the heater, showing the connections of the power supply and the interconnection of individual components.
3. Illustrations of essential features, showing the relation of components.
4. The method of mounting heaters individually or in groups. In the absence of any specific restrictions, it is to be presumed that heater frames may be mounted in contact with combustible materials and heaters may be mounted in close proximity to one another.
5. A caution similar to that indicated in 59.27.
6. The following warning, or equivalent statement: ²To reduce the risk of fire, do not store or use gasoline or other flammable vapors and liquids in the vicinity of the heater.²

Installation

If a heater is intended to be shipped with the legs detached or arranged in other than the intended operating position, clear and complete assembly instructions shall be provided.

Installation

If a heater is intended to be shipped with the heating elements not mounted securely in its intended position in accordance with 10.8, the installation instructions shall include clear and complete assembly information.

Operation

The operating instructions shall contain all appropriate information needed to operate a heater properly, and shall be preceded by the heading ²OPERATING INSTRUCTIONS,”or the equivalent.

Operation

The operating instructions shall:

1. Warn that the heater must be properly installed before it is used.
2. Explain and describe the location, function, and operation of each control of the heater, including all user-operated devices intended to reduce the risk of fire, electric shock, or injury to persons; and warn against tampering with such devices.

Maintenance

The instructions for user maintenance shall include explicit instructions for all cleaning and minor servicing – lubrication, external adjustments, and the like – that should be performed by the user; and shall warn the user that all other servicing should be performed by qualified service personnel. User maintenance instructions shall be preceded by the heading ²MAINTENANCE INSTRUCTIONS,” or the equivalent.