CSA International and Viessmann Manufacturing announce the voluntary exchange of Kromchröder O-RINGS in gas-fired Vitodens 200 boilers

In cooperation with CSA International, Viessmann Manufacturing Company Inc. of Waterloo, Ontario is announcing a voluntary exchange program for Kromschröder O-rings located in the gas valves of Vitodens 200 boilers manufactured during a specific time period. The O-rings may become brittle over time and may potentially cause a gas leak, which may lead to a fire hazard. No incidents have been reported.

Viessmann is asking consumers and contractors to schedule the 10 minute O-ring exchange with the regular annual boiler maintenance, but no later than July 2009.

Vitodens 200 boilers are used for space heating. They are white and wall-hung boilers, bearing the brands “Viessmann” and “Vitodens 200” in silver letters.

The O-ring Exchange Program applies to of natural gas and propane fired Vitodens 200 boilers manufactured between January 2002 and July 2006. To determine if a boiler is affected by this program, please check the 16 digit serial number on a white bar code label on the boiler. If you are unable to locate the serial number, call your certified contractor.

If the serial number starts with the following 7 digits, then please check the 8th digit.


If the 8th digit is 2, 3, 4, 5, or 6, call your certified contractor to perform the O-ring exchange.

Your certified contractor will be able to obtain O-ring Exchange Kits from Viessmann. The exchange itself will take about 10 minutes. If the annual maintenance for your boiler has been scheduled before July 2009, the O-ring exchange may be performed together with the maintenance.

Consumers may find additional information on the Viessmann website at and consumers and contractors may contact the Viessmann O-ring Information Line toll-free at 1-888-414-9157 at any time 24/7 or write to [email protected].

Warning: The O-ring Exchange may be performed by certified contractors only. The installation, adjustment, service and maintenance of this product must be performed by a certified professional contractor who is qualified and experienced in the installation, service and maintenance of hot water boilers.

About CSA International

CSA International is a provider of product testing and certification services for electrical, mechanical, plumbing, gas and a variety of other products. Recognized in the U.S., Canada and around the world, CSA’s marks appear on billions of products worldwide. CSA International is a division of CSA Group, which also includes: CSA, a developer of standards and codes; and OnSpeX for consumer product evaluation services. CSA International can be found online at
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First image for KROMSCHRÖDER Second image for KROMSCHRÖDER

Vitodens 200Location of Serial Number


Anthony Toderian
Senior Media Relations Officer CSA Group
[email protected]