4 Issues That Could Spell Trouble for Your High-Efficiency Condensing Furnace

Owning a high-efficiency furnace is one of the best ways to save energy while enjoying consistent warmth. But as with any furnace, you may run into a few problems that may seem minor at first. However, these minor issues can easily spiral into serious problems that require extensive repairs or even a complete replacement of your furnace.

This post outlines four common issues that could cause trouble for your high-efficiency furnace if they're not addressed as soon as possible.

Unlike a typical furnace, a high-efficiency furnace usually gets its intake air directly from outside through a ventilation pipe. An obstruction in the pipe can drastically cut the amount of fresh intake air available for combustion, resulting in a weak burner flame, incomplete fuel combustion and poor overall performance and efficiency. Such obstructions are usually caused by nesting animals and wayward debris.

One way to tell if an intake air obstruction is causing your furnace problems is by opening the burner compartment cover during operation. If the furnace's performance improves after opening the cover, then there may be an obstruction inside the pipe. Clearing out the obstruction with an auger or shop vacuum may help restore your furnace's performance.

The way a high-efficiency furnace gets rid of its exhaust is also unique. Lower exhaust temperatures allow high-efficiency furnaces to use exhaust vents made from PVC pipe instead of the customary metal flue. Obstructions caused by nesting material and other debris may block combustion gases from leaving the furnace.

Improper installation can also present problems for your high-efficiency furnace. If the intake and exhaust vents are positioned too close together to one another, the exhaust gases can be drawn back into the furnace via the intake vent.

High-efficiency furnaces work by wringing every bit of heat from the combustion gases they generate. As a result, condensation is usually produced as a byproduct of the heating process. The condensate is normally collected within a catch tray and directed through a drain line. Clogs within the drain line or the actual drain itself can cause condensate to back up and leak out of the furnace, resulting in unsightly puddles around the unit.

Fortunately, the vast majority of clogs can be dealt with simply by clearing the condensate drain or drain line with an auger or vacuum. It's also important to watch for blockages caused by mildew and algae buildup.

Some units are also equipped with a pump that actively removes condensate from the furnace. A breakdown of the condensate pump can also result in water leaks. It's a good idea to have a professional test and, if necessary, replace the condensate pump if it proves responsible for furnace leaks.