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.
Possible causes are a bad blower motor, a clogged air filter, blocked or restricted registers, or under-sized ductwork. A high-limit switch trip caused by no airflow (bad blower) will typically occur within 30-60 seconds after ignition.
If your furnace will not stay on, it is usually a dirty flame sensor. This is one of the routines that every homeowner can do to troubleshoot a energy efficient furnace. By cleaning the flame sensor once a season, you can keep the furnace from cycling on and off too fast. Check out more home improvement tips in our e-
The pressure switch is tripped when enough air flow is sensed for ignition to continue. If something prevents an adequate amount of air flow, the switch won't operate, and the furnace will cease to continue firing up.
A heat exchanger replacement is often one of the most costly repairs in a furnace, and the expense can sometimes rival that of installing a new furnace. Typical replacement costs vary widely but can easily reach several thousand dollars, especially if labor costs are factored in.
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.
There are many reasons why a gas stove would stop working, such as the gas or power going out, food debris clogging the igniter, or a broken spark module. Schedule a service professional to assess your gas stove.
A dirty or corroded flame sensor can cause your furnace to keep shutting off unexpectedly. The flame sensor detects if the furnace's burner is lit, and if it doesn't register the flame, it will shut off the gas valve to prevent a gas leak.
A dirty filter blocks airflow, which can stop your furnace from heating up all the way. Be certain that you are changing your air filter when needed, as well as check that there are no large objects stacked around the furnace that are impeding airflow. Keep clean ducts and a clear path.
To begin, ensure that all the filters of your furnace are clean. Also, get the filters replaced every few months to ease the burden on your HVAC system and ensure that fresh air comes filtered into your home. Another common cause of your furnace turning on and off after a few minutes is a faulty pressure switch.
Failed Thermocouple Symptoms
The first is signs of contamination on the tube, which can include discoloration, cracks, or pinholes. Next, check the wiring for any signs of wear or corrosion like missing insulation or bare wire.
My gas furnace won't ignite.
Checking your thermostat is the best place to start. Make sure it's set to “heat” and that you've set the temperature higher than the current room temperature. If that doesn't resolve the problem, try switching your fan to “on” to force the furnace to start working.
Faulty flame sensor
This is a common cause of burners that won't stay on. The flame sensor is a safety precaution in a gas furnace that tests that the gas coming from the burners has ignited.
Your gas fireplace could be turning off for several reasons. The most like culprits are likely tied to some kind of problem with your setup. Anything from issues with your pilot light, clogged ports on burners, damage to heating components, and thermocouple/thermopile malfunctions can be to blame.
The most common cause of this is dirty or blocked burners, which is the part that you can easily take off to clean.
Your Furnace Turns On and then Off Quickly
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.
Blocked vents or a clogged air filter may cause your furnace to run and then shut off too early. It's easy to fix these issues on your own. You should change your furnace filter at least once every three months. Follow our guide to do it yourself.
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?
One of the most common furnace problems is a malfunctioning thermostat. A sure sign your thermostat isn't working properly is if your fan is constantly running. This will cause your thermostat battery to run, and cause your furnace to work inefficiently.
While there's no such thing as furnace or boiler replacement insurance, homeowners insurance may cover the cost to replace your furnace or boiler if it's damaged or destroyed by a covered peril.