Why Does Your Furnace Turn Off After a Few Minutes?

Why Does Your Furnace Turn Off After a Few Minutes?

Have you noticed that your furnace system switches on for a while and the heating cycle abruptly shuts down, and after a few minutes, the heating cycle begins again? This is a strange pattern because the heating cycle lasts 15-20 minutes in a perfectly working furnace system, then takes a break of 10-15 minutes. This is nothing to worry about, but you might need to consult our heating repair expert in Walnut Creek, CA for assistance. 

Reasons That Cause The Furnace System to Short Cycle!

Eight reasons can cause the furnace to short cycle. They are:

1. Faulty Flame Sensor

Flame sensors are used to detect the presence of flame in the furnace system. It is a safety protocol to avoid gas leakage. The flame sensors can get deteriorated due to water droplets formation during combustion.

Flame sensors are thin metal rods, and metal gets easily corroded in the presence of moisture with time. Our heater repair expert in Pleasant Hill, CA, will most likely replace the flame sensor if there are any issues.

2. Overheating

Overheating is a sign that your furnace is working excessively more than it needs to maintain comfort in your home. Overheating can cause the furnace system to shut down temporarily to protect the internal components from damage.

Overheating can be due to a faulty blower motor or, in the worst case, due to a heat exchanger. 

3. Clogged Air Filter

A clogged air filter is one of the common reasons behind several furnace issues. The furnace needs sufficient air to perform the combustion process. However, a clogged air filter restricts the airflow, and the furnace does not get enough air to produce heat.

That’s why our heating repair experts in Walnut Creek, CA, recommend replacing the air filter at the beginning of the winter season.

4. Oversized Heating System

People think buying an oversized heating system will be beneficial as it will quickly warm the room due to its large capacity. However, instead of quick service, it will begin to short cycle, causing an increased strain on the heat exchanger. Thus, it will shorten the heating system’s life.

5. Malfunctioning Thermostat

Sometimes, due to improper thermostat settings, the furnace can short cycle. Before calling our heater repair expert in Pleasant Hill, CA, check the thermostat settings and set it on heat position. Check the fan is set on AUTO mode, and the temperature should be at least five degrees above the room temperature.

6. Dirty Exhaust Flue

A clogged exhaust flue can cause carbon monoxide and other harmful gas to accumulate in your furnace system. It will start affecting the ignition system functioning and cause the furnace to short cycle. 

7. Faulty Electronic Ignition System or Pilot Light

Modern furnaces have replaced the pilot light with an electronic ignition system. Whether you have an old or modern furnace system, if the ignition system delays the starting of the combustion system, it results in short cycling.

8. Air Leaks

Moreover, air leaks and poor insulation can cause the warmth to escape and due to the temperature imbalance in the room, the system short cycles to maintain the desired temperature levels.


The best way to fix the issue is to call our heating repair expert in Walnut Creek, CA, for an inspection. Certified Solar Heating and Air Conditioning experts can quickly help you fix heating issues. Call (925)477-5185 to schedule a service!