Is Your Furnace Short-Cycling?
Does your furnace turn on and off repeatedly for a minute or two at a time - not allowing for your home to reach the desired temperature? It might be short-cycling.
Usually, a furnace will turn on and off between 3 and 8 times per hour, with cycles lasting form 7 to 20 minutes. If you find your furnace short-cycling, there is something causing this. Short-cycling is an early indication something is not right - demonstrating the unit's safety mechanism and preventing something far more serious form happening.
Safety designs like a high limit switch which turns your furnace off before it gets too hot, and a flue limit switch that shuts off the furnace if it isn't vented properly are all things that display malfunctioning furnace issues.
So what are potential causes of furnace short-cycles?
Dirty Air Filter
This is the most common cause of short-cycling. If your filters are dirty or clogged, it won't allow proper air flow to the heat exchanger - potentially causing the furnace to overheat which will activate the high limit switch and shut the furnace off. When it restarts, it will repeat the short-cycle all over again. You can prevent this by cleaning or replacing your air filter.
If your air filter is clean, the next most likely cause of short-cycling is your thermostat. Check the unit's batteries and restart. You may also want to consider the location of the thermostat - is it near a heat source that might be shutting down your heating system prematurely?
Household issues like poor insulation, drafty widows and doors and air escaping are all possible problems that would obviously cause your furnace to run more than needed.
There are many potential causes and parts that could be malfunctioning during short-cycling. The furnace blower, flue and flame sensors, flue limit switch and ignition system are all considerations for a furnace that is acting up.
Wrong Size Furnace
If all the issues above pass inspection, it could just be that your furnace is not correctly sized for your home. If the system is too large for your home, it has more power than needed - heating your home quickly then shutting off. If your furnace starts up more often than needed, you are actual spending more on energy bills, increasing the wear and tear on the unit which ultimately reduces the unit's lifespan.
Whatever problem you may be experiencing from the list above, it is always recommended that you have an experienced and qualified service technician inspect and diagnose the problem.
At 4 Seasons Heating, Cooling & Electrical we are heating experts. We have the knowledge and expertise needed to repair your heating system, but also recommend the best, most cost-effective products for your next HVAC system upgrade. Feel free to call us to schedule maintenance, or a free, in-home, no-obligation sales consultation.