Troubleshooting Guide to Common Furnace Problems in Your Building

It’s nearly time to shut down the air conditioning and start up your furnace for another heating season. When your furnace is up and running consistently, it’s possible you’ll notice that some problems have developed in the way the system works. The following is a brief guide to troubleshooting several common furnace problems. Some of them will require professional assistance, but you may be able to resolve many of them without the need to call your HVAC expert.

Causes of Furnace Problems

• Age: Furnaces are designed to provide many years of reliable service. However, if your commercial building’s furnace is around fifteen years old or older, age will start affecting its performance.
• Wear and Tear: Commercial furnaces receive a lot more wear and tear than residential systems. Over the course of a few seasons, this wear can accumulate significantly and cause functional problems.
• Improper Settings: Improper settings on the furnace’s controls can cause problems that seem severe, but can usually be corrected easily.
  Component malfunctions: Malfunctions of controls, internal components, and important parts can lead to significant furnace problems.
• Lack of maintenance: Commercial furnaces need regular preventive maintenance to keep them working at their best. A furnace that has been neglected will not function properly and will be more likely to develop problems.

Problem: No Power to Furnace

• Check the power cables and connections to ensure they are connected to a functional power source.
• Make sure the furnace’s on/off switch is set to “on.” The switch will often be on the front of the furnace and may look like a standard light switch.
• Locate the building’s main circuit breaker and see if the breaker controlling the furnace has tripped. If your breaker uses fuses, see if the fuse for the furnace has blown. Replace the fuse or reset the breaker.

Problem: Furnace Won’t Start

• If your furnace is a fuel-burning model, check the pilot light to make sure it’s lit. The pilot light is necessary for igniting the fuel that the furnace burns to produce heat. Relight the pilot light if you or your maintenance staff are comfortable with doing so; otherwise, call your HVAC pro for help.
• If your furnace is an electric model, make sure the electronic ignition is working properly.
• Check the programmable thermostat. If the screen is blank, the thermostat needs new batteries. If the thermostat is on, make sure it is set to “heating” and that the temperature settings are higher than the current temperature of the room. Move the settings up a few degrees; this may cause the furnace to turn on and run normally.

Problem: Furnace Produces No Warm Air

• Check the furnace’s air filter to see if it is dirty or clogged. Dirty air filters are a major source of furnace malfunctions since they can block the airflow the furnace needs to work. Put in a new, clean filter. Remember to use a filter that is appropriate for the furnace. If you replace an old filter with a new one that is too thick or dense, you might have more problems related to airflow.
• See if the supply vents or return registers are blocked by furniture, equipment, boxes, or other objects that could stop airflow. Uncover the vents and keep them clear of blockages.
• Check the ductwork of your HVAC system. Missing or damaged ducts could lead to air leaks. Broken seals at duct connections could also let substantial amounts of warm air escape. Repair or replace any missing or damaged duct sections. Connections should all be tight and sealed with mastic or metal tape. Ensure ducts are firmly connected at supply vents and return air registers.

Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection, and Alarm Systems in Mechanical, Commercial, and Residential settings. For more information on troubleshooting common furnace problems in your commercial building, and to view projects we’ve worked on, visit our website!

Photo Credit: PublicDomainPictures/Pixabay