Common causes include electrical problems, a malfunctioning blower motor, or thermostat-related issues. Electrical problems may include blown fuses within the furnace circuit or tripped circuit breakers in your electrical panel.
This can be caused by a couple of possibilities. It's not that you're blower is out of sync, it is either going bad or if this is an older furnace with a fan-limit switch, it is cooling down the heat exchanger too fast (or the unit is underfired) and the fan switch is turning it off.
A furnace cycling on and off repeatedly can be caused by various reasons, from dirty filters and obstructions in ducts and registers to incorrect thermostat settings and faulty limit switches.
Sounds like the blower motor is cutting out typically due to overheating. They have built in overheating protection. It could be from the bearings going out or from running it with a weak capacitor. Best way to test this is to typically direct wire the blower motor and let it run for a day.
There are multiple reasons why your furnace is short cycling. These could include a dirty filter, blocked vent, or malfunctioning flame sensor. You can switch for a clean furnace filter, or have your HVAC technician resolve a more complicated issue.
Insufficient airflow or insufficient gas pressure. A defective, malfunctioning ignition board, flame sensor, light switch, thermostat, thermocouple, fan limiter, or draft inducer fan. The drainage line is blocked, resulting in a full condensate pan. Temperatures are so low that the furnace cannot stay lit.
Short cycling is a common sign of a bad flame sensor. The sensor thinks that there isn't a flame, so it shuts off the gas as a safety mechanism. Except, there is a flame and without the gas to supply it, it dies. This is a frustrating problem, but an HVAC technician can fix it.
Follow these simple steps: First, turn off the power supply to the furnace by turning off the breaker in the circuit box. Locate the reset button on the furnace and press it to reset the furnace. It is usually located inside the blower compartment on the side of the blower motor.
We are going to list them out here and if you want to jump to a specific section you can, but the main reasons a blower motor will stop working at any speed is: A Bad Fuse. A Bad Ground Connection. A Bad Speed Control Module.
Loud Noises When the Heat Is On
If you suddenly hear loud and strange sounds like squealing or grinding, these are symptoms of a bad furnace motor blower that can signal signs of motor bearing problems or a damaged belt in older belt-driven models.
A Bad Circuit Board or Shorted Wire. The circuit board or wiring in your furnace may be faulty, causing the fan to run continuously. This is a complicated problem that requires professional furnace repair.
The simple solution: Turn your furnace off and check the filter. If it's dirty or it's been 3 months or more since you changed it, put a new, high-quality filter in place.
One of the most common causes of a furnace shutting off unexpectedly is low airflow. If your furnace keeps turning off, check for issues such as: Dirty Air Filters. A clogged filter restricts airflow, causing the furnace to overheat.
Most furnaces have a reset button near the blower compartment itself, though the exact location may vary depending on the make and model. It's usually red or yellow and small in size. Consult your furnace manual for guidance if you're unsure where it is.
The fan limit switch controls when the furnace blower fan turns on and off. This control also provides a safety limit that turns off the burner or furnace if temperatures at the furnace get too high. Fan/Limit switches are used on all types of heating furnaces.
Problem 1: Incorrect thermostat settings The most common reason for a furnace fan that won't shut off or a furnace blowing cold air and won't shut off is the wrong thermostat settings. The solution: Check the thermostat settings. The fan setting should be on AUTO. If it's set to ON, the furnace fan won't shut off.
You should inspect your air filter for any signs of dirtiness and replace it annually as most filters require. Another reason why your leaf blower might start and then stall is due to old gas. Old gas that is past its shelf life, which is longer than 3-6 months, can cause a blockage in the fuel filter and carburetor.
Less frequent starts and stops of the fan can reduce the stress from startup, and potentially help extend it's lifespan. Leaving the fan on 24/7 ensures cleaner air, as the air is pulled through the filtration or UV light system. This can be better for people with allergies.
The blower motor contains a capacitor, a device that stores energy to help the motor turn over with a jolt of extra electricity when it first starts up. If the capacitor goes bad, electricity may not reach the motor or it may not have enough electric to power the motor for its initial spin.
Replacing a furnace blower motor costs $560, on average. Depending on the size and type of motor, most people pay $300 to $900. The average blower motor replacement cost is $560, but the final price depends on labor fees, as well as the cost of the parts.
There is a work-around to waiting. If there is no safety risk (like a gas leak), a furnace can be reset to bypass this wait. Turn off the furnace's power switch and wait 10 seconds before turning it back on.
Most furnace flame sensors cost less than $20, but if you opt to have a professional HVAC technician make the repair, you can expect to pay between $75 and $250. Need help replacing your flame sensor?
While most furnaces last for 10 to 20 years, flame sensors have a much shorter lifespan of about five years. Usually, when a flame sensor goes bad, the best route is to replace it outright.