So this is the end result of a failed condensate drain system.  Below are photos of a rusted fuel manifold in a residential split HVAC system.  The interior unit houses the fuel manifold and combustion chamber, among other things.  This area shown in the photos is located behind the removable panel on the front of the furnace.

In this case, the primary condensate drain clogged (failed) and water backed up into the interior furnace unit.  When condensate drain water backs up like this it then proceeds to overflow into the emergency drip pan (if one is installed) that is at the base of the furnace.  It can do so by running down inside the furnace near the fuel manifold, which is bare metal.  The metal gets wet and guess what comes next.  Rust.  Lots of rust. 

If the emergency drip pan has a condensate drain pipe the water will just exit there.  That's good because the backup system worked but it is also bad because the primary condensate drain has failed.  That is why if you ever see water coming out of the "other" condensate pipe outside, call an HVAC technician.  Water should only be coming out of the "normal" condensate drain.  Also, most newer installations of drip pans include a float switch to act as a backup to a clogged (failed) drip pan drain pipe.  If the pan fills with water because the drip pan drain pipe is also clogged, the float switch electrically shuts the system down before water overflows the pan and damages the floor and/or ceiling below. 

All this supports the need for period inspection of major appliances in the home.  At HABITEC Home and Building Inspections,LLC, we offer a Home Inspector's Review to look just for such things as discussed here.  A Review can help prevent these situations from getting out of hand.  In this case, this furnace was heavily damaged and maybe totalled, and it was only 4 years old!

Richard

Comments in this blog posting are the intellectual property of Richard Acree, President, HABITEC Home and Building Inspections, LLC, and contributing members of the Active Rain Real Estate network, and are intended to educate and otherwise assist home owners, sellers and buyers, building owners, sellers and buyers, realtors, real estate investors, property managers, and lenders in the process of owning, buying or selling homes or commercial buildings.  HABITEC is a residential (home) and commercial building inspection company serving Middle Tennessee including Nashville, Brentwood, Franklin, Murfreesboro, Smyrna, Mt. Juliet, Hendersonville, Dickson, Belle Meade, Columbia, Spring Hill and more!  In addition to building inspections HABITEC offers Environmental Services for mold assessments, radon testing and water quality analysis.  Additional information about HABITEC can be found on our website at www.habitecinspections.com, or call 615-376-2753. 

Richard Acree is the founder of the ActiveRain Group Tennessee Home and Building Inspectors.  All are welcome to join and see more blogs like this one.