Maintain Gas Furnace Los Angeles

While it is easy for homeowners to maintain their gas furnaces, any repairs or installation of any gas lines should be left to a certified professional.  The first and most important step when working on your gas furnace is to shut off the gas prior to starting any maintenance or repair on your gas furnace. 
To shut off the gas, follow the gas line from the furnace back to the manual shutoff valve, which is a red-handled valve.  Turn the handle to the off position.  This is usually at a 90-degree angle, or perpendicular to the pipe.  You will have to wait approximately 5 minutes before you perform any work.  
When burners develop a dirty build up around them, this can cause a yellow flame or delayed ignition.  To avoid this problem and an expensive service call, simply clean the burners once a year.  This routine maintenance procedure requires the use of your owner’s manual, because every furnace is different.  If you have misplaced or lost your owner’s manual, please contact the manufacturer of the furnace and request a new owner’s manual.

The following are general instructions for cleaning burners:

Trace the gas line to the burners and carefully examine the fittings and brackets.  To ensure that you can reinstall the fittings and brackets, you will need to take careful notes on how the burners are aligned as well as how they are held in place.   
If the color of your pilot light is yellow or if your pilot light fails to stay lit after you release the control knob, the flame is not getting enough oxygen, which is often caused by not enough heat to trigger the thermocouple.  If however, the color of the fame is mostly blue, then the reason why your pilot light fails to stay lit could be due to the thermocouple. 
Before you start to clean the pilot, make sure to first turn off the gas and disconnect the pilot line from the bracket housing the burner.  Once you have disconnected the pilot line, remove, and clean the nozzle.  You can remove debris by gently blow through the nozzle, or better yet, replace it with a new nozzle.   
When cleaning or replacing the thermocouple, you will need to remove the nut at the end nearest the pilot.  Your next step is to pull out carefully the thermocouple from the bracket.  You then will need to clean carefully the end of the thermocouple.  Your thermocouple should be cleaned yearly to prevent ash and other debris from building up on it.  This build up can prevent the thermocouple from firing the furnace correctly. 
To clean the thermocouple you can use very fine-grit sandpaper to remove any ash or debris.  Once it is cleaned, replace the thermocouple, and then retest the flame.  If again the flame fails to light or is the wrong color, replace the thermocouple.
To replace the thermocouple, you will need to turn off the pilot and cut off the gas at the manual shutoff value.  In addition, you will need to also shut off the power at the circuit breaker or fuse box.  The thermocouple will have to cool down before you can loosen the nuts with a wrench to remove the thermocouple.  After you have removed the thermocouple, take it with you to a dealer so that you will be sure that you purchase the correct one.  Once you have installed the new thermocouple, turn on the power at the circuit breaker, turn back on the gas, and relight the pilot.
If your furnace is less than 10 years old, then chances are it will have an igniter and not a pilot light.  In order to check the igniter, one person will need to watch it as another person turns up the thermostat.  If the igniter does not glow through the observation window, then it may need to be replaced.
To use a multimeter to check your igniter, you will need to unplug the wired leading into the igniter, and then place a lead on each of the igniter wires leading back into the furnace.  Then you will need to set the millimeter to read AC volts.  Turn the thermostat up high enough to start the furnace.  If the meter reads approximately 120 volts, then the igniter is faulty.  If there is no power, then the problem is with the control box.  DO NOT attempt to repair or replace the control box yourself.  You will need to call a service person. 
To replace the igniter, loosen the screw in the bracket, which connects it to the furnace.  You will need to then replace it with an igniter that is of the same model and make, so take it with you to your dealer to ensure that you purchase the correct igniter.
It is important that when you handle the igniter, that you hold it by the porcelain or the bracket.  Do not touch the surface of the igniter because the oil from your fingers can shorten the life of the igniter.  After you have reattach the igniter wires, and screw it in place, you will then turn up the thermostat to test the igniter before you reattach the cover.
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