The Air-Conditioning, Heating and Refrigeration Institute is warning consumers about the dangers of altering any gas-fired heating appliance.

AHRI says manufacturers must use specific engineering and design knowledge to develop gas-fired heating appliances that operate safely and properly under a variety of conditions.

Product designs are tested and certified by third-party independent testing agencies, like CSA International, ETL/Intertek and Underwriters Laboratories for compliance with nationally recognized, voluntary consensus safety standards. Any unauthorized modification to a gas-fired appliance, no matter how minor, can alter the design and compromise the safety of that unit.

For example, the AHRI said an alteration that changes the combustion process might cause carbon monoxide emissions that exceed the limits specified in the safety standards.  Modifications should only be made that are authorized by the original equipment manufacturer or other recognized authority and performed by qualified service personnel.

The institute said that consumers should be aware of companies that offer to make, or instruct consumers about how to make, modifications to various appliances without expressed, written authorization of the OEM.  Consumers should always check with the OEM or their local representative to ensure that a modification is authorized.

“Any unauthorized modification to a gas-burning appliance voids its safety certification and may expose consumers to a risk of property damage, personal injury or even death,” said institute chief technical adviser Frank A. Stanonik.  “AHRI is committed to providing consumers with information on the proper installation and safe and efficient use of gas-fired appliances.”