Know about Furnaces | |
Most newer homes and many older homes are heated with a furnace. This system transfers heat created by burning gas, oil, coal, or by heating a resistance element with electricity to air that is circulated thought out the house. The furnace itself is designed to be trouble free and requires very little care, but the gas or oil burner that creates the heat does require maintenance to run safely and efficiently. General maintenance tips for most type of furnaces are given here with information about servicing particular types by their fuel. The best time of year to service a furnace is in the fall before the heating season begins. The only tools you need are a flashlight and a vacuum. Start by inspecting the outside of the furnace. Look carefully at the flue pipe leading from the furnace to the chimney. Check for loose connections wherever two pipes join, at all elbows and where the pipe joins the chimney. If you see loose sections, push the parts together. Also, check for large rust spots especially on the bottom of the pipes. Condensation may cause rusting and this is a sure sign of a maladjusted burner. If you find loose or missing cement surrounding the pipe where it enters the chimney or large rust spots, call your furnace repair service and have it professionally repaired. All furnaces have some sort of air filter. Most are located in the return air duct system, usually at the bottom of the furnace where the large duct enters the furnace. This filter requires regular replacement if it is not a permanent foam-type filter. Replaceable furnace filters come in many sizes and can be purchased from most hardware stores, lumberyards, and home centers. In the spring, purchase a supply of these filters when they go on sale. If you have central air conditioning, you will need to replace these filters all year long. To change a filter, all you have to do is slide the old filter out and replace it with a clean filter. One side of the filter is clearly marked showing how to insert it into the furnace so it is most effective with the correct side facing the incoming air. Your furnace may have a U-shaped filter called a hammock filter. This type of filter is located at the bottom of the furnace below the blower assembly. To get at it, you have to remove an inspection panel from the side of the furnace. To remove it, lift the wire frame off of its rack and push it together, then pull the filter directly out of the furnace. The filter element will most likely be made out of a fiberglass batting that can be purchased at hardware stores or home centers. Remove the old filter and throw it away or cut a new piece of filter material from the roll and wrap it around the wire frame. Both flat and hammock filters may have a permanent filter element. It is made of foam or other filter material that can be cleaned and reused. Remove it and give the filter a good vacuuming, then wash it in warm water and a mild detergent. Check with the manufacturer of your particular furnace for specific cleaning instructions. A furnace has a blower that forces the air through the heating system. Some blowers have a V belt drive that should be serviced every year. Some newer furnaces have direct drive blowers and are not belt driven. Both systems require cleaning and a little oil. The furnace blower is usually located in the bottom of a typical upright furnace right behind the furnace filter. There is an access panel in the side of the furnace that opens up or comes off to expose the blower assemble. BEFORE STARTING, MAKE SURE THE POWER IS TURNED OFF TO THE FURNACE AT YOUR MAIN CIRCUIT PANEL. The blower is controlled by the thermostat. If the power is not turned off and someone turns up the thermostat while you have your head in the furnace, the blower will begin to operate. You don't want to get tangled up with a blower or get your hand caught in the belt. The furnace is safe to work on WITH THE POWER OFF. On most belt drive blower assemblies, both the blower motor shaft and the fan shaft require yearly oiling. If you see small spouts with little covers on them at either end of the motor or blower shafts then you should oil the unit. Fill the oil cups with 20-weight machine oil, but don't over oil because the excess will just run out and collect dirt. Direct drive units may or may not require oil, consult your owner's manual for specific directions. If there is a drive or V belt, inspect it for cracks or frayed areas. Replace it if it looks at all suspicious because they're an inexpensive item. If the belt fails some cold night, an emergency service call may become an expensive reality. Loosen the hold-down bolts that secure the motor assembly and push the motor towards the blower to slacken the belt. Many furnaces have printed instructions on how to change the belt on the inside of the removable panel. Remove the V belt and take it to your local hardware store or home center and purchase a replacement. Reinstall the belt in the reverse order that you removed it. Check that the tension is correct. If you push the belt in the center between the pulleys it should deflect at least a 1/2 inch. Don't over tighten the belt as this may cause excessive bearing wear in the motor or blower. If the furnace is equipped with a humidifier, it requires at least yearly maintenance. Electric Furnace Electric furnaces are extremely efficient and the actual heating elements have no moving parts. Besides general yearly maintenance outlined above for the furnace, there is not much you can do to keep an electric furnace operating efficiently. Even though the electric furnace is efficient, electricity is an expensive fuel. Dirt and dust in the system will cut down its efficiency. Regularly clean the registers in each room with a crevice tool of a vacuum to remove dust balls and dirt. Dirty registers that are partially blocked with a buildup of dirt will restrict the amount of air that can pass through the duct and lower the efficiency of furnace and cost you money. Gas Furnace Gas furnaces run very clean and their burners require minimal maintenance. Besides general yearly maintenance outlined above for the furnace, a major tune up of a gas burner assembly should be left to a professional. There are several easy maintenance procedures that you can safely perform that will go a long way to keep the furnace in top shape. MAKE SURE THE POWER IS TURNED OFF TO THE FURNACE AT YOUR MAIN CIRCUIT PANEL. The gas burner and furnace blower are controlled by the thermostat. If the power is not turned off to the furnace and someone turns up the thermostat the burner will light. Turn the circuit breaker serving the furnace off before you start any maintenance work. The gas burners are located in the central portion of the furnace. The front panel will usually lift off to expose a row of horizontal tubes. Check the owner's manual for specific directions to remove this panel. The burner tubes lead inside the furnace and are part of the burner assembly which is basically the same as a gas stove only they are larger. Along the top of these tubes are the burner heads with small holes for the gas air mixture to come out and be burned. Vacuum up any flaking rust particles or other debris from the top of the burner heads. Dirt will block the small holes and prevent the burners from operating efficiently. Also vacuum up any dirt under the burner assemblies and any dust or cobwebs from the front openings of the burner tubes. Don't try to adjust any of the safety controls and have the furnace professionally inspected and tuned up every couple of years. A properly adjusted gas burner will save you money in the long run. Oil Furnace An oil furnace is a rather complicated piece of machinery and requires regular maintenance to keep it working efficiently. Servicing the many controls and safety sensors on an oil furnace should be left to a trained oil burner service technician. An annual fall tune-up will pay for itself over the next heating season because an oil burner out of tune can be very inefficient. There are, however, some maintenance procedures that you can safely perform to keep an oil furnace operating efficiently. First and foremost, keep the burner clean and free of dirt. An oil burner digests large amounts of air used in combustion which passes through the air intake port on the side of the blower housing opposite the motor. The burner housing gets oily and attracts dirt. If the air intake becomes partially blocked, the burner will not operate efficiently and you will be loosing precious heat up the chimney in the form of excess smoke. Keep the burner housing clean and the air intake ports clear. There are oil cups at the end of the burner motor. Put a few drops of 30-weight machine oil in the cups once a year. Over oiling can damage the motor so don't do it if a service technician does during a yearly tune-up. Changing the fuel oil filter is another job that is messy but not difficult. Look on the top of the filter housing and record the name of the filter and the model number. Call a local heating oil supplier or burner service to see if they have a filter element. Most likely, they will stock the filter, if they don't have that particular number ask them to recommend a comparable filter element that will make a suitable replacement. Make sure you find a replacement element for the filter before you take it apart. Replacing the filter element is easy. Turn off the oil supply at the valve at the bottom of the tank. Place a bucket under the filter and loosen the bolt in the center of the filter top. Some filters have a bolt at the bottom of the filter bowl. Use an adjustable or open end wrench to loosen it. If the bolt is very tight hold the body of the filter to prevent it from twisting and bending the copper lines connected to the filter. When the bolt is loosened the bottom of the filter will drop off. Some older styles may have a T-handle that you turn to loosen the top. Dump the oil in the filter bowl into the bucket and remove the old filter element. Replace the element, then soak the new gasket in oil and replace the gasket around the top of the filter bowl. Reassemble the unit in the reverse order. Next bleed the air out of the system. Open the small bolt on the top of the filter and turn on the oil. Wait until you see some oil start to run out of the bolt hole, then tighten the bolt. If the top comes off leave the top on loosely until oil starts to leak out around the top, then tighten the T-handle to seal up the filter. Turn the power back on to the furnace and turn up the thermostat to fire up the burner. It should start to fire right away but the furnace may shut down if a small amount of dirt gets into the burner system. If it does, push the reset button on the relay box and try again. When the burner fires up let it run for a while even if it's warm outside to make sure all the air is out of the system. After about five minutes turn the thermostat down so the oil burner goes off to turn off the furnace. Written by the editors at HouseNet Copyright HouseNet, Inc. |