Heating season is coming soon and with it the time for Fall maintenance. Some home and building owners don’t believe they need to have their gas heating systems checked. They believe, “It’s not necessary to service gas, only oil burners need service.” Gas providers should take a lesson from the oil industry and get the word out about the necessity for preventative maintenance.
High efficiency gas furnaces and boilers need annual “tune ups”. For this high performance gear it’s not as simple as just changing the filter and which filter type we should use. Some homeowners will go to the box stores, buy their own filter, and install it themselves. This is a fact of life in the HVAC world. But are they buying the right filter for their system? Some filters on the market will “only stop a kitten” as they say, while others are too efficient for some systems. The resistance that some filters put on a system can be too much for some air handlers to overcome. This is also a problem when ductwork is either inadequate or too small. The wrong filter magnifies these ductwork issues. The furnace that whistles with a normal filter is going to be starved for air with a higher MERV filter. The box stores advertise that a MERV 8 filter is a “good” filter, a MERV 15 is the “best” filter. This is not necessarily true unless the system was designed for that level of resistance.
When we go to a home or up on a roof for our annual maintenance, we are not there just to change the filter. The first thing we should do, as professional technicians, is to do a visual inspection of the heating system and where it is located. How many times have you gone into a basement and are unable to locate the furnace because they finished the basement around it? The furnace has been put into a closet without any consideration for combustion air. This would not be a problem for a two pipe 90%+ furnace, but for the single pipe 80% furnace, it is definitely an issue. We should also look for water stains, cracks in the flue, and air leaks in the duct work. Back to our filter; is it installed properly, and is the access to the filter sealed and not open to the basement air?
Now that we have done our visual inspection of the exterior of the system, it’s time to take the cover off. Before we shut the switch off, we should be checking to see if there are any error codes. Should there be, you can address them during this visit. How many times have we heard, “It was working before you came”? At this point, you will want to check the ignitor with an OHM meter making sure not to touch it. If it’s questionable, recommend replacement. It’s better to address it now rather than having to return for a no heat call, again hearing, “It was working before.” The safeties on the furnace should be checked to make sure they work shutting off the furnace should there be a problem. The manifold pressure should also be checked. Unless you are the installer, you cannot be sure it’s ever been checked.
Next, we check the furnace, making sure it is not over firing or under firing. Make sure to check the hoses in the furnace. They do dry out and can leak water, which could lead to corrosion and electrical problems. We should then be checking the flue pipe for any water leaks, missing or broken hangers, as well as leaves or other debris in the intake or exhaust. Leaves can get in the intake and plug up the screen on the furnace, if there is one, or end up in the combustion chamber.
The condensate pump should be checked next for proper operation. If the system includes air conditioning which has run all summer, it could be full of slime. Flush it out and make sure the discharge is clear. Don’t forget the trap on the furnace as well. This could be full of debris and may also need to be cleared.
Okay, we’ve checked the furnace and its components. Now check the temperature rise through the furnace. Always check the manufacturer’s recommended Delta T. 50 degrees is a good average. Remember the finished basement, did they block or remove some of the ductwork or crush it because it was too low? All of this should be inspected.
By providing a complete maintenance/tune up, equipment will last longer, the customer will be happy, and who knows, more work may come as a result of your professional service.