Why Is My Commercial Furnace Not Working?
A commercial furnace giving out on a cold Delaware winter day is no small problem. At the very least you’ll hear complaints from everyone in the building. At worst, you’ll have to shut down operations and lose hours of productive time. You could also end up with frozen pipes if the indoor temperature falls low enough. A number of issues that can cause a furnace malfunction are things you can take care of yourself. Others require help from a technician.
Cover the Basics
Make sure your system has power. It might sound obvious, but switches can be accidentally bumped and cords absent-mindedly pulled out. Check that the power cord is plugged in and system is turned on.
Look in the fuse box for a tripped circuit breaker or blown fuse. It’s safe to reset the breaker or replace the fuse once, but if the same thing happens again it means you have an electrical malfunction that requires professional repair. If your system runs on oil or propane, make sure there’s fuel in the storage tank. You might have run through your supply faster than you expected.
Once you know your system has power and fuel, take a look at your thermostat. It should be set for “heat.” The temperature selected must be higher than the room temperature in order for the furnace to kick on. A thermostat set for 65 degrees might not turn the furnace on at all if the weather is mild. Try raising the temperature by around five or 10 degrees, then waiting five minutes. The system should kick on to meet the higher temperature selected.
If your thermostat runs on batteries, put in a fresh set. Low batteries can cause a thermostat to malfunction even if the LCD screen is lit. Finally, check your thermostat’s user’s manual. The thermostat may have switched into a mode that prevents it from calling for heat.
The air filter in a commercial furnace can also cause it to shut down suddenly. A neglected filter will accumulate a layer of dust and debris that interferes with airflow into the furnace. If the airflow is reduced too much, the motor will become overworked and could eventually catch fire. Fortunately, this is unlikely because modern heating systems have a safety mechanism that shuts the system down when the airflow falls too low. Check your air filter and if it’s dirty, put in a clean one.
Where a Professional Can Help
If the furnace won’t ignite properly or the pilot light keeps going out, a worn out flame sensor or thermocouple is a likely cause. This device shuts off the fuel supply when the burner flame goes out, but if it’s malfunctioning and can’t detect the flame, it will unnecessarily prevent the furnace from running. Replacing the thermocouple on a commercial furnace is a job best left to a professional who can get the new part in place quickly and safely.
Inadequate combustion air can cause your furnace flame to go out repeatedly. This is a dangerous problem that should be addressed by a professional as soon as possible.
If your furnace’s blower fan motor runs, but the system doesn’t produce heat, there could be a problem with the thermostat, ignition system or electrical wiring.
Lack of routine maintenance can also cause your commercial furnace to stop working. Dust and dirt buildup alone can prevent some components from doing their job.