Jump to content

gas & oil in same flue

Recommended Posts

That flue is likely oversized and has been causing flue gases to condense on its sides for decades. Being acidic, those gases trash the clay liner. Of course, the gas burns at a lower temperature so those gases will cool sooner. Also, if it's a gas appliance with a 24/7 pilot those gases from the pilot will be condensing all the time.

It happens with both oil and gas flues so I wouldn't peg it to just mixing the two so much as I would to an oversized flue.



Link to comment
Share on other sites

Yes. Mixing oil and gas fired appliances in the same clay-lined flue causes deterioration much sooner than same-fuel equipment. Also, changing from oil to gas equipment and utilizing the same flue results in rapid deterioration of the clay liner as well. The condensate from the gas appliance, combined with the sulfur deposits from oil-fired equipment results in rather aggressive sulfuric acid.

I always encourage relining with both the above. It'll need it sooner rather than later. As Mike stated, the flue dimension is often oversized for the updated equipment anyway.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...