Heating System Problems
Heating System Will Not Run
- First, go to the thermostat and turn the Fan switch to ON and see if the blower comes on or not. The Fan switch is normally left on Auto, but when you manually switch it ON, that commands the blower to run. With some units, there may be a short delay (30 seconds) before the blower starts. If the blower does not come on, then continue with this section. If the Fan (indoor blower) runs when the Fan switch is ON, then at least you are getting power to the furnace and at least one function works (Fan) - go to the “Fan Runs” section below.
- If the Fan does not run with the Fan switch set to ON, that suggests a power or control problem. If your furnace is in the attic or garage, make sure that the power switch on the side of the unit has not been turned off by accident. Also check the circuit breakers in the garage (or wherever your main electrical panel is located). Gas heating systems use electricity for blowers and control systems but it’s highly unusual for a gas furnace to trip a breaker - this is something to get checked by a professional.
- Read the Owner’s Manual that came with your furnace. It will have specific troubleshooting and safety information
- If the indoor blower (Fan) doesn’t run, the furnace won’t work either. At this point, a service call is required.
Fan Runs (switched to ON) but Heating System Does Not Produce Heat
- Check to see of your hot water heater is working. If it works, then at least you know you are getting gas (to the house). But check to make sure the water heater pilot is actually lit. You can have hot water for several hours even if the gas is off.
- Check the thermostat. It should be set on “Heat” and the desired temperature should be set higher than the house temperature. Fan should be set to “Auto.” The “On” position just controls the fan. Programmable thermostats may be set incorrectly, so override the program to make sure the thermostst is not at fault.
- If your furnace has a pilot light, check to see if it’s lit. Lighting instructions are on the furnace. Use a long Bar-B-Que lighter, not a piece of paper. If you don’t want to tackle this yourself, give us a call. A pilot light that goes out frequently may indicate a problem with the furnace. Do Not try to manually light a furnace that does not have a standing pilot light (most newer furnaces don’t have them). Read the instructions on the furnace door or the owner’s manual before doing anything.
- If the indoor blower runs but the furnace does not produce heat or just blows cold air, and you’ve tried the above, a service call is necessary.
Heating System Runs but Shuts Off Before House is Warm
- If the heating system starts up, but shuts off (or blows cold air) after a few minutes (before the house gets warm), this may indicate that the furnace is overheating and an internal safety switch is shutting it down. You may have really dirty filters blocking the air flow through the heating system. Or it could indicate a serious problem with the burners or furnace vent. This is a hazard which should be checked out immediately by a service technician.
If your filter is the “permanent” washable kind, replace it with a disposable filter. Permanent filters can block too much air even when clean. Check and make sure all registers are open and that no filters are installed in the registers. If changing the filter and opening all the registers doesn’t fix the problem, you’ll need a service call.
If you smell gas, call the gas company from a neighbor’s phone. Don’t use the phone (or a cell phone) in your house until the leak has been fixed.
Heating System Questions
Q: What is Carbon Monoxide?
A: It is a gas produced by burning fuels that contain carbon. It is odorless and colorless, so you can’t detect it by smell. Carbon Monoxide bonds with hemoglobin in the blood more strongly than Oxygen and can cause asphyxiation. Symptoms include dizziness, trouble thinking, sleepiness. If you suspect Carbon Monoxide, get to fresh air immediately and get medical attention. Also, never use a barbecue indoors for supplemental heat. In fact, don’t use any supplemental heater indoors unless it is labeled for indoor use.
Q: Do I need a Carbon Monoxide detector?
A: Your heating system should be checked at least once a year to make sure it’s not producing Carbon Monoxide and the heat exchanger is not leaking. If the flame is not producing Carbon Monoxide and the heat exchanger isn’t leaking, then you’re OK. The flame is usually not the problem, but heat exchanger welds can crack, causing leaks. The only way to tell is to have it inspected. Since Carbon Monoxide detectors are not very expensive, every home should have one.
Q: What causes heat exchangers to crack?
A: Heat exchangers get hot, then cold, then hot again, up to 3 or 4 times an hour during the heating season. These thermal stresses can crack the welds in the heat exchanger causing leaks. What appears to increase the incidence of heat exchanger cracking is overheating. The heat exchanger heats the air in your home, but at the same time, the air in your home cools the heat exchanger. Something as simple as a dirty air filter can reduce the cooling air flow across the heat exchanger which causes it to overheat, which leads to warping, cracking and leaking. Duct work that’s too small or closing too many air vent registers (or even clogged A/C coils) can have a similar effect. It used to be that heat exchangers didn’t leak until they had been in service at least several years, but with many new homes being built with duct work that’s too small and restrictive, it’s not unusual to see heat exchangers developing leaks even in the first season. For this reason, don’t shut off air registers unless you know you are still going to have adequate air flow.
Q: Can heat exchangers be repaired?
A: The short answer is no, they must be replaced. Many are still under a parts warranty (you would only have to pay for labor). In any case, there is no alternative. Heating systems with leaky heat exchangers are dangerous and can’t be operated until replaced.
Air Conditioning Problems
There are not many air conditioner problems which homeowners can fix themselves, but there are a couple of things to check before you call for service.
If your air conditioner is not cooling like it should, use the following troubleshooting info to identify the problem.
Indoor Fan Will Not Run
- The indoor blower is the fan that blows the air around inside your house (not the fan on the unit outside). The blower must be working or the Air Conditioner won’t work either. To check the indoor blower, turn the Fan switch on the thermostat from Auto to On. This should turn the blower on (there may be a 30 second delay, so be patient). If you can hear the blower come on, check for air at the vents. If you are getting little to no air from the vents but can hear the blower running, the filter may be dirty, or the A/C may be low on Freon (which causes the indoor coil to freeze over and block air flow). See “Indoor Fan Blows But A/C Unit Does Not Cool” in the section below. If the blower does not come on, check the following, but keep in mind that the blower motor itself might be bad.
- Check the circuit breakers. A “tripped” circuit breaker is in the middle position halfway between on and off. This should be readily noticeable. Find the tripped breaker and turn it off and then back on to reset it. The outside disconnect box may use fuses instead of breakers or may simply be a pull-out switch (in which case, your breakers are in another electrical panel - either inside or outside). If your outside disconnect uses fuses, you’ll have to either check them (with a meter) or replace them with new fuses you know are good. Frequently tripping breakers or blowing fuses (more than once every few years) indicates an electrical problem that should be checked out. Tripping even once should be looked into. It could be caused by an overloaded unit and is a sign maintenence is required.
- If the fan still won’t run, turn the A/C off and give us a call. Running the A/C when everything is not working correctly can cause more extensive damage.
Indoor Fan Blows But A/C Unit Does Not Cool
- Check the air filter. Really dirty filters can block flow and cause the inside coil to ice over. If the coil is iced over, you can hear the indoor fan run, but you will get very little air (maybe none) from the vents. If you suspect an iced coil, change the filter, open all registers and keep the unit off for an hour or so to let any ice melt from the coil. While a really dirty filter or too many closed registers can cause a coil to ice, this condition is usually caused by a Freon leak - thawing out doesn’t fix that. If you see some ice in or around the outside unit, that is a sign the unit is low on Freon. Turn the A/C off - a service call is needed.
- If the indoor blower runs and provides plenty of air but the air is not cool, check the ouside unit. With the thermostat set to Cool, the fan on the oudoor unit should be running. If not, check the outside circuit breakers (see above).
- If the outside breakers/fuses are OK but the outside unit doesn’t run (the outside fan is not running), turn the A/C OFF and give us a call. Running the A/C when everything is not working correctly can damage it further.
- If the fan on the outside unit is running, check the temperature of the air blowing from the outside unit. On a properly working Air Conditioner, this air should be about as warm as a hair dryer. If it’s not warm, the A/C unit is not working. A service call is required. If the air from the outside unit is really hot, the unit may be overloaded or needs cleaning.
- If the air coming from the outside unit is warm (nearly hair dryer hot) but the inside air is still not cool, check the outside coil for debris (leaves, grass) or blockage (shrubs). Turn the A/C off at the circuit breaker and clean the outside coils with a garden hose to remove any debris that may be blocking the air flow and trim back the shrubs (provide at least a two-foot clearance around the unit). After cleaning the fins and trimming the shrubs, turn the A/C back on and check for cooling. if this doesn’t solve the problem, turn the A/C unit off and give us a call.
Outside Pipe Ices or Frosts
- There are two copper pipes connecting the outside unit to the inside unit (some A/C units are built with everything in one package and in that case, the copper pipes are inside, but may be visible). If one of those pipes has ice or frost on it, it usually means the system is low on Freon. Running the A/C when it’s low on Freon can damage the compressor, and keeps the unit from cooling as well as it should.
Water in the Drain Pan and Other Water Problems
- The A/C system removes moisture from your house and that water should drain freely from the white plastic pipe. If there is water in the drain pan (in the case of indoor A/C systems) the plastic pipe could be clogged, or the unit could be low on Freon (which causes the indoor coil to ice up, blocking proper drainage). Either condition needs to be checked out.
Air Conditioning Questions
Q: How often do I have to change the filter?
A: You should check the filter about once a month, but you shouldn’t have to change it every month unless you have pets, do a lot of cooking, or have hobbies that produce dust.
Historical Note: The A/C filter was originally designed not to keep your house dust free, but to keep the A/C coil from getting blocked with dust. The A/C coil is wet from condensation, and anything the filter misses can easily stick to it, blocking air flow, robbing efficiency, and eventually requiring a coil cleaning. Household dust plus the condensation water on the A/C coil form a perfect medium for growing mold and bacteria. After 5 or 10 years, you’d be surprised to see all the gunk that can build up on the A/C coil. Some are so bad that they block air flow, increasing summer cooling bills. We’ve seen some that have blocked the furnace too, causing the heat exchanger to overheat.
Q: What can I do to cut my electric bill?
A: The biggest problem is attic heat. Some attics can get 130 degrees or hotter in the summer. Attic insulation can only do so much. You need to vent that heat out of the attic. Make sure insulation hasn’t fallen into the soffit vents and blocked them. Most houses don’t really have enough attic ventilation and need an attic fan. A small fan can remove a lot of heat at a low cost. Another thing to check is to make sure your duct work isn’t leaking. Leaky ducts account for about 10-20% of your A/C and heating bill. Repair leaks with duct tape. Also, make sure plants, leaves and other debris are not blocking the outside unit. Rinse the outside unit’s coils at least once each summer (turn the A/C breaker off first). Shading the A/C unit with trees can cut its operating cost by 10%, but shrubs should be kept trimmed (about two feet from the A/C unit) so that air flow is not restricted. Finally, get your A/C unit professionally inspected once a year.
Q: Why is my house so humid?
A: If your A/C is working correctly, you may be overloading it with moisture from showers, the dish washer and washing machine. Use the vent fans in bathrooms and the kitchen to remove excess moisture. Of course, your A/C may not be working like it should. It only takes a few simple temperature and humidity measurements for us to tell if your A/C unit is working properly and is removing moisture as it was designed to do. Many indoor Air Quality problems are due to the A/C unit not removing enough moisture.
Q: What causes mold problems?
A: Moisture. You can’t completely eliminate mold spores or sources of food (wood, wall board, paint, carpet) because that’s what your house is built from. You can’t make the temperature too extreme for mold, because you couldn’t live there either. However, mold has to have moisture to live. A broken pipe, leaky roof or other direct source of water can cause mold to grow out of control. But high humidity can also support mold growth, and that’s the most common reason people complain of mold. You can reduce the humidity in your home several ways (see above).
Q: Can I run the fan on my A/C system all the time?
A: Yes you can. In fact, with some two-story houses, that may be the only practical way to keep the upstairs or bonus room at a reasonable temperature.
Q: Why does one of the pipes going into the outside A/C unit have ice on it?
A: Usually, this means the Freon charge is wrong. It may have too much Freon, but this is not likely unless the unit has been worked on recently. More often, it means there is a leak and the unit does not have enough Freon. Continuing to operate an A/C unit with low Freon means your A/C is costing a lot more to run than it should and can also damage the compressor.