Over the last century, boiler controls have evolved significantly. Initially, technological advancements in infrared and ultraviolet flame detection enabled automated systems to replace 24-hour boiler operator presence. Over the past 25 years, the advent of electronic controls has enabled the possibility of even more advanced systems, improving both safety and efficiency in the industry, requiring changes to the standards.

Across many areas of the certification landscape, from residential to industrial products, a desire to provide a comprehensive service solution where requirements can be aligned globally has been motivating the industry to harmonize requirements with internationally based standards instead of individual regional documents, further driving the need for these changes.

Heating equipment is implemented sufficiently different in the North American marketplace as standards are generally anticipated to be kept regional; however, the control systems and components at the core of these products can be designed such that a single platform can be used throughout the world.

Recent regulations in motor efficiency and electromagnetic compatibility generally require that advanced, brushless, or pulse-width modulated motors are used, with switching power supplies and power factor correction becoming a de facto requirement to meet the more stringent performance standards. The advantage of utilizing these more advanced systems is that the power input is no longer limited to the 60-Hz systems of North America and can be used without change globally.

However, product safety standards have not kept pace with these technological advancements, and developing new requirements based on global standards of the International Electrotechnical Commission (IEC) provides the fastest path to both update the safety standards to reflect the newest technology and a common path for market access in any corner of the globe.


Global transition

This transition to global standards for controls requires a paradigm shift, as each region must be responsible for bringing critical safety concerns to the global stage to truly harmonize requirements. At present, many national differences identify specific issues particular to each region; however, over the last 20 years, the IEC 60730 series of standards has been published with differences by UL and CSA for the U.S. and Canada, respectively, providing a common and consistent platform for giving true global market access.

In addition to the shift in philosophy behind regional committees, an alignment of terminology is needed. The basic safety principles adopted by the IEC are no different than the basic principles in place in U.S. and Canadian standards written over the last century; however, there are different terms used, and the document used for product certifications are structured differently. 

IEC standards are organized by hazard instead of having distinct “construction review” and “performance test” sections as seen with typical UL and CSA standards. This framework allows easier adoption of requirements across various product applications and fosters consistency between such applications.

They are organized by ‘general’ requirements that apply to all controls (IEC 60730-1) and have “particular’ requirements (IEC 60730 “Part 2’s”) that modify these requirements for specific applications. For limit and burner controls, the relevant Part 2 requirements are:

  •  UL 60730-2-5 / ANSI Z21.20 / CSA C22.2 No. 60730-2-5 for Burner Controls;
  • UL 60730-2-6 / CSA E60730-2-6 for Pressure Controls;
  • UL 60730-2-9 / CSA E60730-2-9 for Temperature Controls; and
  • UL 60730-2-15 / CSA E60730-2-15 for Water Level Controls.

The transition period for certified safety (protective) controls used in limit and burner control applications has been established to extend five years beyond the transition for non-safety (operating) controls by request and agreement from the responsible Standards Technical Panels. On Oct. 19, 2018, the deadline passed for these non-safety controls, and all new model certifications and updates to certification reports involving alterations for controls evaluated to UL 873, the Standard for Safety for Temperature-Indicating and -Regulating Equipment; UL 244A, the Standard for Safety for Solid-State Controls for Appliances; or UL 60730-1A, the Standard for Safety for Automatic Electrical Controls for Household and Similar Use, Part 1: General Requirements must be evaluated to the requirements of UL 60730-1/CSA E60730-1 and the appropriate Part 2 requirements (or CSA C22.2 No. 24-15 in Canada).

For the “legacy” requirements of UL 353, UL 372, and ANSI Z21.20-2005 and -2007 editions, after Oct. 19, 2023, all controls and components previously certified to these standards will continue to be certified so long as no changes are made to the product that requires reevaluation. However, for product standards that continue to reference these “legacy” standards, a system evaluation can be done to certify the system with the control using these obsolete requirements.

After this date, any changes to the control or component that require reevaluation will necessitate that they comply with the latest edition of UL 60730-1 and the associated Part 2. After this date, all new limit and burner controls and components shall be evaluated to the latest edition of UL 60730-1 and the appropriate Part 2 applicable requirements. All limit and burner controls and components evaluated to earlier editions of UL 60730-1 will continue to be UL-certified so long as no changes are made that require any reevaluation. After this date, any changes to the control or component that require reevaluation will necessitate that they comply with the latest edition of UL 60730-1 and the appropriate Part 2 standards.

Currently, manufacturers may have UL 353 and UL 372/ANSI Z21.20-2005/-2007 certified controls and components evaluated to UL 60730-1 and the appropriate Part 2 requirements. UL 353, UL 372 and ANSI Z21.20-2005/-2007 will remain valid certification standards through Oct. 19, 2023, when they will be effectively obsolete. At that time, UL 353, UL 372, and ANSI Z21.20-2005/-2007 will no longer be used to certify new controls or components.

The next milestone was just reached, as the latest edition of IEC 60730-1, Edition 5, Amendment 2, was published in April, and the version to follow will be restructured to better organize the topics and information to reduce redundancy and be easier to read. IEC 60730-1, Edition 6, will initiate this restructuring, which will then be adopted by the various national committees and relevant Part 2 Standards in the years to follow, providing a streamlined framework for certification.

This summary merely skims the surface of this transition and all that it entails. Contact UL to attend a webinar or schedule a workshop to confirm your controls are compliant with the updated standards and ask how your product can be put on the fast path to global market acceptance with a single series of tests.