Why does the O-ring need to be exchanged?

The Kromschröder gas valve O-rings are tested continuously as part of ongoing quality assurance. Over time some O-rings have become brittle when exposed to unfavorable conditions. Although no incidents have been reported, a brittle O-ring could lead to a potential gas leak and fire hazard. As the O-rings do not meet our stringent quality and safety standards, we are voluntarily requesting that all affected O-rings be replaced.


Does the O-ring of my boiler need to be exchanged?

The exchange only applies to Vitodens 200 gas-fired wall-mounted condensing boilers manufactured between January 2002 and July 2006. If you are not certain if your boiler is a Vitodens 200, please see the picture on the right. These white boilers are wall-mounted and have the name "Viessmann" and "Vitodens 200" imprinted in silver.

The serial number affixed to the boiler will indicate when the boiler was manufactured, and if an O-ring replacement is required. Your certified HVAC contractor can locate the serial number of your boiler and determine if an O-ring exchange is needed. Viessmann will provide your contractor with the tools and information required to complete the exchange.

Vitodens 200

Is there any danger?

Although no incidents have been reported to us, a brittle O-ring may lead to a gas leak, potentially causing a fire hazard. We are voluntarily requesting that all affected O-rings be replaced, as they do not meet our stringent quality and safety standards. Viessmann has also informed the safety authorities as a precautionary measure.


My boiler is propane-fired. Should the O-ring be replaced?

Yes. The exchange should be conducted for propane- and natural gas-fired Vitodens 200 boilers manufactured between January 2002 and July 2006. Click here to see Does the O-ring of my boiler need to be exchanged?


When should the exchange be done?

It is best to perform the exchange as soon as possible to exclude any potential risk. You may combine your annual boiler maintenance with the exchange.


Who will pay for the exchange?

Viessmann will provide all replacement O-rings free-of-charge and a monetary labor contribution to contractors performing the exchange.


How long does the exchange take?

Your certified HVAC contractor can perform the exchange in approximately 10 minutes.


I just bought a house with a Vitodens 200. How do I know if the O-ring has been replaced?

The serial number affixed to the boiler will determine if an O-ring exchange is required. To exclude any risk, Viessmann recommends that you contact your certified HVAC contractor who can locate your boiler's serial number and determine if an O-ring replacement is required. Click here to see Does the O-ring of my boiler need to be exchanged?


I have questions not in the FAQ. What should I do?

Please contact our O-ring Information Line at 1-888-414-9157, or email us at o-ring@viessmann.com.