The units were manufactured prior to March 5, 1999, and sold throughout Canada, mainland United States, Alaska, and overseas.

The retrofit also includes heaters manufactured under private label for Modine Manufacturing Co. (HEX4 Series), Crouse-Hinds (EXH4 Series), Stelpro Heating (XUH Series), and Ouellet Electrical Heating (OAX Series).

These industrial heaters are primarily used to heat buildings in the energy industry. Other users include pulp and paper mills, coal mines, hazardous waste storage facilities, and waste treatment plants.

Since the introduction of the XL4 heater in 1993, three rupture incidents have occurred. According to Ruffneck, property damage was minimal and there were no injuries.

Following inspections by a third-party engineering firm and in-house testing at Ruffneck Heaters, it was determined that XL4 heat exchangers can develop internal gas pressure that may lead to an eventual rupture.

The company is asking anyone who uses an XL heater or its private label equivalent to register with Ruffneck immediately in order to receive details of the retrofit program.

For more information, or to register a heater, visit www.rhretrofit.com (website) or call 403-291-5488; 800-661-8561 (toll-free in the U.S. and Canada).