Furnaces

The common home heating solution

Furnaces can be powered by fuels like oil, natural gas or propane, or with electricity. The most common types found in residential homes are electric and natural gas furnaces.

Natural gas furnaces generate heat by burning fuel. The hot gas resulting from this combustion passes into heat exchangers (curved metal tubes), which transfer the heat to air flowing through the home’s air ducts and into the home. Gas furnaces create carbon monoxide, a colorless and odorless gas, that’s released outside through a vent or pipe. Carbon monoxide poisoning occurs when a crack or leak forms in your gas furnace, allowing CO into your home. This is why installing carbon monoxide detectors within the home and having your furnace serviced annually are so important.


Electric furnaces are both cleaner and safer than gas furnaces. However, they are also twice as expensive to run. Electric furnaces use electricity to create heat with wire coils. Air is forced into a heat exchanger via an air fan and enters the home through a duct system.

Furnace Filters

Your furnace filter is key to the efficient operation of your furnace and the air quality in your home. Although some furnace filters are very inexpensive, many of them will only catch about 75 percent of bulk dirt and 3 percent of minute pollutants.

Treated furnace filters are generally more effective. These disposable furnace filters are treated with dirt-trapping glycol or mineral oil. They may only capture about the same amount of bulk dirt, but they can catch about 10 percent of the smaller, microscopic particles. Most disposable filters are made of fiberglass or carbon and cost less than $10 online. You should replace your furnace filter every month, or as needed, to cut down on heating bills.

Electronic furnace filters or electrostatic air filters are the most effective. Some brands claim to remove up to 97 percent of large particles and 70 percent of microscopic particles. Most permanent furnace filters range in price from about $60 to $400 online for a complete unit. These can often last for years, but need regular cleaning to stay effective.

Thermostats

Your home’s heating and cooling systems are controlled by a small piece of equipment called a thermostat. Today, most homes have a digital thermostat with a programming option.

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Digital thermostats are preferred over mechanical thermostats because they can be programmed to raise or lower the temperature automatically at set times of the day. This way, for example, you can avoid heating the house when no one is home during the day. Digital thermostats measure temperature by means of a thermistor. This is an electrical resistor whose resistance change depending on temperature. A microcontroller measures the resistance in the thermistor and converts it to a temperature reading. The thermostat turns the furnace on or off based on this reading, to maintain the temperature you have programmed.

Your thermostat should be located in a room that is used frequently. In order to read your thermostat easily, it should be installed at eye level. It should also never be placed on an outside wall, near a window or be exposed to direct sunlight or other heat-conducting appliances.

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I have one bedroom in my house that is always cold; there is barley any air coming out of the vents when the heater is on. What could be the problem?
Posted on 1/6/2010 7:34:00 PM by Anonymous
How do you replace the water in a radiant heat furnace?
Posted on 12/11/2009 6:11:00 PM by Anonymous
I had a call on a York Affinity 9.c gas furnace. The blower motor had a burnt component in the motor end cap. I replace the coplete motor and component section because you cant buy them seperetly. The unit started operrating properly. I went to check the space no heating . There was a code stuck pressure switch. reset next code was stuck open pressure switch. Replace the pressure switch with one frome another unit that was working properly. The same codes came u p again with another flame present without power to gas valve. This wasnt happening. Swapped boards with another unit didnt make any difference same pressureswitch codes keep coming up. I replaced the board back into the other unit i swapped the board from now that unit is doing the same thing. Can you help
Posted on 12/6/2009 12:04:00 PM by Anonymous
I have a coleman/evcon furnace. It would come on and blow for 2 minutes and shut off for no particular reason. I replaced the flame sensor and no luck. GOOD NEWS THOUGH; the fix was quick and cheap. The furnace filter was clogged like you wouldn't believe. So I went and bought a new one replaced it... voila! THe problem is there there are sensors to tell if air is going past the burners so they don't over heat.. Insufficient air flow means the sensor will kick out and tell the furnace to stop because there is a problem I sincerely hope this post helps.
Posted on 12/5/2009 8:33:00 PM by Anonymous
your service guy should have reset your fan settings to original you had, sound like the setting have been changed or wire is off timer board or rep[laced on WRONG terminal (blargh)
Posted on 12/1/2009 7:05:00 PM by Anonymous
when my furnance did your symptoms the one way plurge water run off value was plugged and would not clear water from furnance , pull your lower water run out lines to see if water is standing ))
Posted on 12/1/2009 7:03:00 PM by Anonymous
I have an issue with my gas furnace. Sometimes it makes a loud noise -like a small explosion when it turns on, the blower then comes on about a minute or two later. It appeared to have started after I had my furnace cleaned. Any idea what might be going on?
Posted on 12/1/2009 6:28:00 PM by Anonymous
How do I remove a firepot assembly from a Johnson J-8812?
Posted on 11/15/2009 10:22:00 AM by Anonymous
I have a model Payne 396 furnace. The fan will not shut off unless the power is shut off, even when the thermostat is on the off position. The heater portion is not working. I have shut down and start up numerous times but the same conditions exist.
Posted on 11/9/2009 10:42:00 PM by Anonymous
Hi,I just had a new oil furnace installed after the guy who cleaned my old one told me I needed a new furnace. The new furnace doesn't keep my house warm. The guy told me my old furnace was too big for my house so he installed a smaller one. My fan use to be really srong and blow the hot air in the room. Now the air blows in really slow and is warm not hot,you can barely feel it. The heater kicks on and only stays on for a couple of minutes and then kicks right off. My house is freezing. I called him and he told me that the air shouldn't blow hard into the room.,I think thats ridiculous how is the air suppose to get into the whole room if it barely blows in,it only warms the area around the vent.He also said it was because my vents are too small,which is wrong because they worked just fine with my other heater which was larger. The guy said he will have to come out several times over the next few weeks to fix it. It is getting colder everyday,I think he is just stalling. What should I do. I don't know anything about furnaces and I'm starting to think my old one was fine and he just lied to sell me a new one that doesn't work.
Posted on 11/7/2009 1:06:00 AM by Anonymous
can you help me find parts for a coal/wood FLO-CO steel furnace
Posted on 11/2/2009 6:26:00 AM by Anonymous
Hey rad to forced air guy, I went for a smoke and got thinking about your situation. There is no reason you should be freezing. When was the last time your boiler was serviced? Is it running low temp? Boilers do strange things joe homeowner wouldnt think of. It could need simple cleaning. Call your local guy and request a boiler mechanic. There are few around and most techs don't know the first thing about them. Toss things out like "do you think it may be air locked?" "could the expansion tank have lost its air bladder or be full?" If he looks at you like you have 3 heads hes not your guy. Those old cast iron pigs hold alot of heat and back in the day most were oversized to begin with. It could be as simple as adjusting your outdoor reset. There are many configurations and methods of control but you certainly should not be cold providing you didn't tack on a few monster additions to your home.
Posted on 10/31/2009 4:07:00 AM by Anonymous
Understand that your thermostat is a switch only. Just like a light switch. (Unless you have a fancy thermostat designed for a very high end system. ie. Carrier Infinity $300+ most less costly systems pretend) Your furnace will simply do its thing until the thermostat sees the temperature it likes and opens the switch. You don't want HOT air from your furnace, warm is good. Hot creates uneven heat in the home you will feel hot/cold/hot/cold. All furnaces are designed with a minimum and maximum "temperature rise". This is the difference in temperature of the air entering the furnace and leaving the furnace. It sounds to me like the fellow that cleaned your furnace may have recognized it running too hot and changed the airspeed (higher) to bring the temperature rise down. He should have told you about this. Call the company and request that the specific tech who was at your house call you and explain the situation. It is important you simply ask to speak with the tech. You will find them much more helpfull if you do not explain the situation to the office folk. To the fellow with the coleman. Any time a furnace shuts down and will not start unless you cycle the power you have a big problem. This means the machine has "locked out" usually on a safety. It locks out to protect itself and avoid burning your house down. Call your coleman dealer asap! Your playing with fire. Get rid of your oil mess and that big ugly tank in your basement just put in a nice little gas furnace. In the end you will spend more time and money never mind drive yourself crazy with this conversion nonsense. It is a major undertaking to convert a house with rads into forced air. This means you have to tear up floors and cut up walls to run ductwork through your house to get supply and return ducts to the areas required. Should you choose to do this you get what you pay for. There are lots of guys that will tell you they can bang it in and its no problem. The fact is it needs to be engineered to work properly. All these ducts need to be sized appropriately its not just a bang it in thing. A good tech can do the math and should request drawings or spend all kinds of time measuring up your house and running various calculations, should be able to provide you with a spec drawing before he picks up a tool. Very costly... 3 switch flicks makes no sense... most air conditioners have a time delay installed to protect them. flick once and wait 10min if that doesnt work could be a thermostat problem? strange. GO STEAM GO!!!! I like steam myself, to each their own.. no cheap way, your whole system is designed to run steam with traps and the whole bit. Get out your engineer don't pay bottom dollar it will cost you more in the end. Sorry about the bad news, hope I was of some help.
Posted on 10/31/2009 3:51:00 AM by Anonymous
I just had my high effiency oil furnace professionaly cleaned, it seems now i have to turn the thermostat higher than normal to get any heat, it seems i am gettin only warm air not hot when the furnace is on????
Posted on 10/22/2009 6:34:00 PM by Anonymous
instruction booklet for Armstrong Air gas furnace
Posted on 10/12/2009 10:40:00 AM by Anonymous
We have a coleman gas furnace - Model GM9S100C16UP11H - Seriel WOF5306050. The unit is about four or five years old. When advancing the thermostat ten or more degrees, the unit runs for about thirty minutes, then shuts off without achieving the desired temperature and won't restart unless the power switch is turned off and then on again. The red light in the indicator panel flashes red. Once the power switch is turned off and on, the unit proceeds to reach the desired thermostat setting and continues to function properly the rest of the day. Should we advance the thermostat only two or three degrees at a time, the unit achieves the desired temperature and then shuts on and off normally. We can continue to advance the temperature on the thermostat several times until the desired temperature inside is achieved and the unit seems to function properly. Can you give us some clues as to what the problem might be?
Posted on 10/7/2009 8:54:00 AM by Anonymous
can a oil furnace be converted to a gas furnace easily?
Posted on 10/2/2009 4:08:00 PM by Anonymous
right now i have two fuel furnaces heating my 2story, 7 bdrm house! How do i change the whole heating system into forced air. My house is old and it still has water radiators to heat house. none in 2 bedrooms. none in 2 bathrooms and in the kitchen. I need a change Im tired of heating this house every winter and freezing my butt off. also use electric heaters every where to stay warm. its dangerous but its all i can afford. I need a new heating source all around. Do u have any suggestions for me before Winter reaches here? Its like September 27,2009 now
Posted on 9/27/2009 2:09:00 AM by Anonymous
My thermostat will not turn on my AC automatically or when I intially turn it on unless I flick the switch on and off 3 times. However the furnace comes on without a problem. What could be the problem.
Posted on 9/26/2009 10:47:00 PM by Anonymous
how can I change from steam to hot water heatin gin an old house without breaking the bank?
Posted on 9/20/2009 7:24:00 AM by Anonymous
i was trying to find recalls on your furnaces but your link doesnt work
Posted on 9/3/2009 1:26:00 PM by Anonymous
We resently purchased a new home,and the furnace and central air unit were ran for who knows how long without a filter, now when you try to run the air, only the tubes leading into the coils gets cold,what should i do Call your heating and cooling person in your area and get them to pull out you A coil and clean it for it probably plugged up and freezing up .... but you big line the one with the insulation wrapped around it will always be cold and sweat its supposed to!
Posted on 8/28/2009 9:14:00 PM by Anonymous
is you fan switch turned on on your stat or your summer switch on your furnace turned on or you could have a a bad control board if you furnace is new enought
Posted on 8/28/2009 9:10:00 PM by Anonymous
electrical motor will not shut off. the fan is not on, the heat or a/c is not on but the electrical motor stays on.
Posted on 8/20/2009 11:13:00 PM by Anonymous
are Payne gas furnace warranty transferable?
Posted on 8/16/2009 3:48:00 PM by Anonymous
air conditioner will ot turn on
Posted on 8/6/2009 7:46:00 PM by Anonymous
How do I change filters in a Coleman 8632 furnace
Posted on 7/7/2009 11:47:00 AM by Anonymous
how old is my carrier ac unit? Model # 38EN024301. Serial # Y316539?
Posted on 6/27/2009 2:47:00 PM by Anonymous
I need a free estimate for an air conditioner and possible furnace replacement. I woudl like to do this in the next five days.
Posted on 6/26/2009 4:58:00 PM by Anonymous
If the blast sensor is out on my Pyane furnace would that cause my centeral air condensor not to work?
Posted on 6/22/2009 11:29:00 AM by Anonymous
We resently purchased a new home,and the furnace and central air unit were ran for who knows how long without a filter, now when you try to run the air, only the tubes leading into the coils gets cold,what should i do.
Posted on 6/13/2009 8:34:00 PM by Anonymous
I have water flowing from the overflow cap over the burners a and an excessive amount of water in the drain pan. where could it be coming from?
Posted on 6/13/2009 2:18:00 PM by Anonymous
What is it when you see particles flying in the air - new filters or furnace needs cleaning - how do you know?
Posted on 5/31/2009 9:59:00 AM by Anonymous