Dear Comfort Advisor,
I read my furnace manual and it suggests annual maintenance. What do I need to look for and can I do it myself?
Dear Do-It-Yourself Dave,
Modern furnaces require a bit more attention than their older counterparts. The technological advances of newer furnaces allow for higher efficiency but also make proper maintenance critical. Automobiles are similar in this way. My old ‘67 Camaro is devoid of just about any electronics and can be fixed with a screwdriver and a 9/16” open-end wrench. But I also have a 2008 Honda that I wouldn’t even consider doing anything more than an oil change on. In a modern furnace, there are some things that you can do, but many of the critical checks require specific tools and test instruments. The most important but often neglected home owner task is changing or cleaning the filter(s).
Most modern furnaces have a condensate drain and the components need to be removed and cleaned. Sediment builds up in them and a clog will cause a failure. The flame sensor is another simple but critical component. It really needs to be cleaned annually because even a small amount of dirt build-up will reduce the flame current and cause a failure. A good vacuuming always helps but there are many tubes, pipes and wires that should not be disturbed. If the motors have oil ports, oiling them will extend the life of the motors.
Once the above mentioned tasks are complete, more technical analysis is required. We use Bacharach digital exhaust gas analyzers to accurately check and document the chemical make-up of the flue gas. This is the only way to know how efficient the unit is operating and how safe the exhaust gas is as it leaves the unit. The gas company has limits as to how high the carbon monoxide levels can be before the furnace must be repaired. It can be extremely dangerous and inefficient to operate a heater in a poorly-tuned condition. If you really think about how many times your furnace has turned on and off in the last year, it is really amazing that they run as well as they do.
Other tests include temperature rise measurements that determine how much heat is being removed from the furnace through the ducting. This is done with a couple of digital thermometers placed properly in the ducting. Oftentimes the temperature rise is beyond what the manufacture states on the data tag and duct pressure must be checked. This is done with magnehelic gauge that can be mechanical or digital. The pressure that the furnace blower creates in both the supply and return can be checked against the information in the furnace. It is called total external static pressure and too much makes for noisy and inefficient operation.
Many other heating appliances including boilers, electric furnaces, and heat pumps have stated specifications on the equipment that need to be referenced to ensure proper and safe operation. Dirty filters, dirty blowers, closed registers, blocked return grilles, and leaking ducting absolutely negatively impact your systems operation. Many of the manufacturers will base future warranty decisions on the maintenance that did or did not occur. While there is some attention you can personally give to your heater, if you want it done to the factory specifications, you need to contact a heating and cooling professional like the ones at AirWorks Inc.