There is, I think, some controversy about gas furnace inspections. Should it ever be inspected, or should you just wait for something to break and then get it repaired? What about “maintenance?”
These are both good questions. Let’s take a look at them… Maintenance is, generally speaking, a good idea. The concept more or less revolves around the thought that a gas furnace should be “tuned up” on a regular basis. The odd thing is, when we are talking about modern gas furnaces there is surprisingly little to adjust or lubricate. Traditional “tune-up” tasks on older (what I call “antique”) gas furnaces would involve things like lubricating the blower motor and the blower wheel shaft, tightening the blower drive belt, checking the alignment of the belt sheaves, and adjusting the gas burner air intake shutters. None
of these tasks are present in modern gas furnaces. Instead, blower motors are direct drive (no drive belt or sheaves), motors are permanently lubricated, and burners have fixed air intakes (no adjustment possible). So, if you have an antique furnace (definition: it has a pilot light and no draft inducer), these things should indeed be inspected and dealt with. Modern gas furnaces, though, have very little to keep up with from a “maintenance” point of view. There are some things that should be done such as cleaning the flame sensor and, in the case of a high-efficiency furnace, cleaning the condensation drain system. For the most part, maintenance mainly consists of cleaning, especially the air filter. Which brings us back to that first question, why not just wait for something to break? Well, you can certainly take that approach, but I wouldn’t recommend it. The biggest and best reason for a regular gas furnace inspection is safety. Even though modern gas furnaces are typically loaded with safety devices, these things can and do
fail. Also, there are some failures that furnace safety devices simply cannot detect reliably. Besides, who wants to have a furnace failure in late December when you have a house full of guests? Now there is no guarantee that a furnace inspection can and will prevent an unexpected and inconvenient failure, but you have a much better chance of consistent and safe operation if it is looked at on a regular basis.
-Gordon McIver