I wish I could put down my broad brush of criticism—-but I can’t—and I have tried—it is the same issue over and over and over.
The HVAC person that you use may not have to be painted with my broad brush—but perhaps they would as well.
It is very common to call for servicing of heating equipment in the context of the home inspection. I am perpetually amazed at what “servicing” means to these guys. I have had to become much more “proactive” in specifying exactly what I want included in “servicing”—-otherwise things rarely look any different “later” than they did “before.”
For example, did you know that it is “unusual” for servicing to include checking for carbon monoxide? (I think this is essential on older equipment especially)
Or that it does not include vacuuming dirt and debris out of the interior of the furnace compartment?
That it does not include inspection of the interior and exterior of the furnace venting system? (I think it is this aspect that bothers me the most)
Lets take a typical furnace that has not been serviced for a while and the inspector notices large amounts of white “condensate” all over the vent connectors, inside the furnace compartment and perhaps all over the floor. The combustion by-products of a gas furnace contain slightly acidic moisture. Under normal furnace operation this particulate is vented to the exterior of the home. For various reasons it can condense inside the vent and drip out of the pipe connections and back into the furnace or onto the floor—leading to corrosion of furnace components and/or the venting system itself. Here are a couple of pictures of what this condensate looks like.
It forms on the surface much the same way efflorescence forms on a concrete surface. As the moisture evaporates the particulate gets left behind and builds up over time.
If the HVAC Service Person comes in and services the unit and leaves all of this condensate in place how is anyone coming later going to make any kind of reasonable statements related to its presence? We would be foolish to assume that it means nothing just because there is a sticker on the furnace that states it was serviced yesterday.
There can be lots of causes of the presence of condensate at furnace components and almost all of them are not good—-hence the reason inspectors will call for the furnace to be serviced.
It just feels really weird to call for servicing when it was just serviced yesterday—-or even a month ago.
The next two vent pipe pictures were taken in the attic. The vent pipe is for a furnace that had a service record that showed “annual” servicing. It takes a long time for vent pipes to get to this sorry state—-a lot longer than a year.
Why wouldn’t checking this pipe—both inside and out—be a routine part of every furnace servicing?
I have seen bees completely block a vent during the summer when the furnace is not being used and then the furnace does not vent properly when fired up in the fall.
I am done venting now—-so is the furnace.
Charles Buell, Real Estate Inspections in Seattle
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