Modern heating and cooling systems are more sophisticated, than in years past. In order to make them more energy efficient, they are more electronic and computerized.
However, this means that there are more things that can go wrong. Here are some things to consider when your Carrier furnace keeps shutting down.
Reading the manual
Get out all of the papers that you have on the unit. Check to see if it is under warranty. Carefully go over the details of the way the model works. If you have an older model, it may have a pilot light. Newer ones will most likely have igniters.
Many heat systems shut down as a safety measure. As most use gas heat, they must have a shut down system. This is to prevent any natural gas from entering your home. Check the shut down system in your unit. Something may be tripping it.
You may have an older model that uses a pilot light. Check to see if the pilot light is on. In some cases, you may get air or bubbles in your gas line. This can cause a pilot light to go out. The light will also be out, if the thermocouple is bad.
A thermocouple is a device that works with two dissimilar metals. When heat is applied, it causes an electric current to flow. This current energizes a gas valve. As long as the current is flowing, the gas valve is on. If the current stops, the valve shuts off.
At the end of the metals is a probe. This probe fits so that a pilot light flame touches it. This keeps it hot and allows the current to flow. You will need to hold down the button and light the pilot light. Now make sure that the flame is touching the probe. If not, there are two things to do.
You might need to move or adjust the position on the probe. You may need to increase the gas flow to your pilot light. You should clean any soot from it. Often times the pilot light hole can become dirty. This makes the flame smaller. It cannot reach the probe. The slightest puff of air may be enough to shut down the unit.
If the thermocouple is completely bad, the pilot will go out when you release the start button. In some cases, it will stay lit for a while, and then go out. If the pilot keeps shutting off after adjusting and cleaning, replace the thermocouple.
These parts are not expensive. They can be purchased at your local appliance parts store. They are fairly simple to remove and install.
Igniters glow very hot to ignite the gas for your burner. There is also a flame sensor. This does a similar job to a thermocouple. The thermostat will send a signal to the igniter. It will get hot.
The flame sensor will detect the heat from the flame. A long as there is heat, it will keep the gas on. If for any reason the flame goes out, the sensor will shut the gas off.
Some sensors use metals like thermocouples. Others work on an optical principle. The best things to do with these things are to keep them clean. Make sure that there is no dirt or soot, anywhere.
Be careful when checking anything else. Make sure that there is no power going to the unit. If you pull any panels, check for loose or disconnected wires. Look for any fuses, too.
Look for any grounding wires. A loose ground may cause problems. These wires will be green or bare. If this does not fix it, it is best to call a technician.
Your carrier furnace keeps shutting down. Get out the papers. Look to see if it is under warranty. If it has a pilot light, look to see if it is on. The pilot light hole may be dirty with soot.
Check the thermocouple. Make sure that it is touching the flame of the pilot. If the pilot keeps going out, you may need a new thermocouple. They are not hard to replace. They also are not expensive.
If it has an igniter, make sure it is clean. Look for any loose wires in the control panel. Make sure that everything is well grounded. If this fails, you will need to call for professional help.
Originally posted 2010-09-05 09:47:44.