Warren Technology Warren Technology


The attached materials ("Tabs") relate to the issues addressed in the Cover Letter and Safety Bulletin. These materials are available to provide additional, more detailed information on the issues ("Presentation") or to support the representations made therein ("Reference").

TAB 1: Backup Overheating Protection in Unitary Electric Heaters
PRESENTATION: Overview of the backup safety protection requirement issue.

  1. UL1995 30.11
  2. UL1995 30.16, 30.17, 30.18
  3. UL1995, Table 39.5 - Maximum Acceptable Temperatures for Operation
  4. Temperature-Limiting and Temperature-Regulating Thermostat Control Defined
  5. ARTLC Manufacturer's Warning of Unreliability
  6. Failed ARTLCs
  7. UL1995, Section 46
  8. UL1995, Section 47
  9. UL1995, Section 48

TAB 2: Industry Response & UL1995 Misinterpretation by Certified Lab
REFERENCE: Industry's perspective on the interpretation of the 30.18 exception.

TAB 3: Response to Industry Misinterpretation
PRESENTATION: Analysis of misinterpretation of safety standard & other backup issues

EXHIBITS: (Please refer to Exhibits 1-9 in "Tab 1", above)

TAB 4: Temperature Ranges relating to Heater Operation
PRESENTATION: Temperature ranges of heater operation and the purpose of the Primary automatically resetting control and Backup Protection.

  1. UL1995, Section 46
  2. UL1995, Section 47
  3. UL1995, Section 48
  4. UL1995, Table 39.5 - Maximum Acceptable Temperatures for Operation
  5. Types of Devices - Designs and Illustrations Relating to Safety
  6. UL1995 30.16, 30.17, 30.18

TAB 5: Backup Protection Devices must be Reliably Safe
PRESENTATION: Differences in reliability between potential backup devices or designs is absolutely critical when the consequence is exposing people to fires in their homes. One is too many if it can reasonably be avoided.

  1. UL1995 30.16, 30.17, 30.18
  2. ARTLC Manufacturer Acknowledgment Warning
  3. Failed ARTLCs
  4. Manufacturer Warning - Mechanical Replacement
  5. Failed Mechanical Replacement
  6. Types of Devices and Designs and Illustrations Available for Safety

TAB 6: UL1995 Safety Standard - October 2011
REFERENCE: UL1995 Current Revision

TAB 7: Photographs
A. REFERENCE: Failed Automatically Resetting Control -- CAUSE

TAB 8: Recent Collection of Some Failed Devices
REFERENCE: The automatically resetting controls in this photo have each failed in the closed circuit position. This sample contains exemplars returned by some installers who serviced Warren heaters in which the voluntarily incorporated backup protection was triggered by excessive temperatures and, in turn shut down the heater before any fire could occur.

TAB 9: Product Bulletin for ARTLC & Non-Resettable (Replaceable) Device
A. REFERENCE: ARTLC manufacturer's warning - Not Reliable.
B. REFERENCE: Microtemp Thermal Cutoffs Introduction - Not Reliable.

TAB 10: Home Fires Involving Heating Equipment
REFERENCE: NFPA 2012 Report: Home Fires Involving Heater Equipment (by National Fire Protection Association). National study identifies home fires in 2006-2010 caused by electric powered central heating equipment. The report identifies 3,390 fires are caused by electric central heaters in American homes each year. While 540 fires were reported as caused "Automatic Control Failures", precisely, other more general causes reported could, and probably do result from the unprotected failure of the automatic controls. For instance, "Failure to Clean" reduces air-flow and the resulting hazardous temperatures create a fire (220 fires per year), or "Unclassified Mechanical Failure or Malfunction" certainly would describe the failure of the contacts to open on an unprotected automatic control, as well as "Unclassified Electrical Failure or Malfunction" (1,270 fires per year, combined), etc. (See page 68).