Twenty Common Winter Heating Problems

Twenty  Common Winter Heating Problems

If you are experiencing heating issues this winter, search AC Dave’s list of “Twenty Common Winter heating problems” to see

Twenty Q&A Heating system problems

if we can save you some money.

A heating system that doesn’t turn on when expected can incite panic among homeowners. This common heating problem doesn’t necessarily mean the furnace or heat pump is bad – often, simple problems are the reason why the system doesn’t turn on.

  1. No power to the thermostat

The thermostat controls all communication to the furnace or heat pump – if it doesn’t have power, it doesn’t tell the heating system to start up and heat the home. Fixing thermostat power issues includes replacing batteries, verifying tight electrical connections, and verifying the power supply at the home’s electrical panel for hardwired thermostats.

  1. No power to the heating equipment

If no electricity goes to the heating system, its components will not activate even when the thermostat instructs them to do so. A tripped breaker or flipped the external power switch on the furnace, air handler, or outdoor heat pump may be the reason why.


  1. Improper thermostat settings

Simple thermostat errors prevent heating equipment from starting when expected. Ensure the HEAT setting is selected and verify that any programmed temperature adjustments are correct.

  1. Loose access door

If the door to the furnace or air handler’s blower compartment is loose or not properly closed, this may prevent the system from starting when instructed. Some models have this safety feature to prevent accidents and damage to blower components.

  1. The heating system shuts off shortly after coming on

Heating equipment typically cycles for 10 to 15 minutes at a time. When the system starts up and shuts down again within a minute or two, this issue is known as short cycling. Short cycling has many causes – despite its cause, this issue causes damage to the HVAC equipment and discomfort in the home, leading to higher heating bills and more frequent system repair needs.

  1. Thermostat malfunctions, faulty electrical connections

dirty temperature sensors, improper location of the device, or even an unlevel older mercury model are all issues that cause short cycling stemming from the thermostat. Gentle cleaning of sensors, recalibration, repositioning, or replacement may be used to solve these issues.

  1. Improper thermostat anticipator calibration

Some older manual thermostats have adjustable heat anticipators which warm up the thermostat’s interior to end a heating cycle prematurely. This is done in anticipation of residual heat in the ducts, allowing it to reach the living areas while avoiding overheating the space. Improper calibration of the anticipator can end heat cycles too early, causing short cycling. They can be adjusted, or the entire thermostat can be upgraded.

  1. Overheating can be caused by poor airflow

Dirty air filters and closed room vents restrict airflow through the furnace, which causes interior components to overheat. The furnace’s limit switch shuts down operation when internal temperatures are too high for safe operation. Replace the furnace filter and check all room vents to ensure they are fully open. A blocked flue pipe can also cause furnace overheating – blockages must be found and cleared not only to prevent short cycling but possible carbon monoxide exposure in the home.

  1. Faulty Flame Sensor In Furnace

The flame sensor detects the presence of a flame when the furnace’s gas valve is open, working to prevent dangerous gas leaks and explosions. When it becomes dirty from soot, it may not detect the flame and the system shuts down shortly after starting as a safety measure. The existing sensor can be cleaned or replaced if broken, as corrosion is a common cause of damage to the component.

  1. Faulty furnace draft inducer motor

Many newer furnaces feature a draft inducer motor that exhausts combustion gases leftover from the prior heating cycle. If its air pressure switch does not detect proper airflow through the heat exchanger, it shuts the furnace down as a safety measure. This malfunction may be caused by an obstructed flue pipe or a fault in the pressure switch or the motor itself.

  1. Oversized heating equipment

When a heating system is installed that is too big for the home, it produces more heat fast – this is not a good thing. Air heats up quickly, and the thermostat shuts down the heating cycle once the set temperature is detected. Repetitive short cycles wear out components, leading to higher energy consumption and equipment breakdowns. Replacement is the only solution.

  1. Incorrect blower fan settings

If cool air comes from the vents, it could be due to a constantly running blower fan. Using the ON setting keeps the fan on all the time rather than only during heating cycles – when the heating system does not run, the fan blows cool, unheated air through vents into rooms. Using the AUTO setting avoids this issue.

  1. Dirty furnace filter

Clogged air filters prevent proper airflow through the heating system, which may cause the heating system to overheat. While elements of the furnace or heat pump that produce heat shut down, the blower may still operate, moving cool air into rooms.

  1. Lack of heating fuel

Furnaces often use natural gas, liquid propane, or heating oil to fuel combustion. If fuel reserves are empty or utility gas service has been disrupted, the furnace may come on, but combustion will not occur; therefore, no heat is generated. Refilling fuel storage can correct this issue for liquid propane or heating oil furnaces. Utility outages or damage to gas lines may need to be investigated for natural gas furnace models.

  1. Closed gas valve

A closed gas valve prevents fuel from moving to the ignition system, so the furnace cannot combust fuel to produce heat. The blower motor may still run, but only cool air comes from the vent because no heat is made. The gas valve position can be adjusted, and faulty gas valves are replaced if the valve is stuck in the closed position.

  1. Faulty ignition

If the ignition system fails to initiate, no flame is produced in the burners to combust heating fuel. Ignition issues have many potential causes, from the unit’s pilot light to malfunctioning ignition components, which are detailed in the section below. How to fix a faulty ignition may be possible through do-it-yourself steps or require professional HVAC repair.

  1. Significant duct leaks

allow a large volume of heated air to escape the ducts while allowing cold air infiltration from the surrounding unconditioned spaces. If the furnace runs a heating cycle properly, but rooms receive cold air, drastic heat loss through ducts may be at fault.

  1. Condensate line clog

In high-efficiency condensing furnaces, blockages in the condensate drain line can disrupt system ignition. Clogs or incorrect drainage due to damaged components can cause the furnace’s pressure switch to open as it detects condensate accumulation. Proper drainage must be restored, and excess condensate must be removed before the furnace ignites properly. This issue is often intermittent, as condensate drains and builds back up within the system.

  1. Closed vent louvers

Some vent covers have louvers that open and close to control airflow from the vent. If these louvers are mistakenly closed or become stuck in a closed or partially closed position, airflow into the room is restricted. The space may not receive adequate heating. Check the position of the vent louvers and adjust to solve this issue. When louvers become stuck, it is sometimes possible to repair them. Replacing the vent cover corrects this issue when closed louvers are damaged beyond repair.

  1. Duct leaks

Duct leaks prevent the proper amount of heated air from reaching the room instead of allowing it to escape elsewhere in the home. It is possible to assess the ducts for leaks and make repairs if they are accessible. Professional duct sealing methods provide more reliable repairs and correct issues impacting inaccessible ducts. Not enough return air vents. A home’s duct system is carefully designed to balance the return of air from the interiors back to the heating system. Too few return air inlet vents cause low airflow from room vents due to pressurization – how to fix this airflow issue and the last of the Twenty Common Winter heating problems issue requires the assistance of an experienced HVAC professional.

AC Dave Heating & Air is Licensed and ready to Help. Please call us if you are experiencing any of the twenty Common Winter heating problems and would like us to look at your heating system. Tel: 661 270 1961

LIC #877683


By AC Dave

AC Dave has been in the HVAC field for the past 40 years. AC Dave is involved in every aspect of every job. A C Dave Heating & Air was established in June of 2006. AC Dave wanted his company to be a reflection of all the great things he learned over the years working in the field from Customer satisfaction #1, to honesty and pride in his work.

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