Odor complaints are common. There are many different types of odors and different causes but for the most part they can be broken down into five different categories.
Odor problems can be as serious as a gas leak or as simple as a dirty air filter. But remember, a good mechanic doesn't just use his hands. He uses his ears and nose. Unusual odors could indicate a serious problem and should not be ignored.
We will go through each of the five categories and list the possible causes and things to check.
Sometimes loose electrical connections cause wires or plastic relays to overheat causing electrical odors.
It is possible for a very dirty air filter to cause the odor. If the airflow is restricted enough, it could cause electric resistance heaters to overheat, even burn-out.
If you smell an electrical odor, check your air filter. If it is not blocked, shut off equipment at the breaker if possible and call for service.
It can also be debri such as plastic getting into the ductwork and melting on the electric resistance heaters or heat exchanger.
If you smell a burning odor, check your air filter. If it is not blocked, shut off equipment at the breaker if possible and call for service.
Having said that though, don't take a gas odor lightly. If possible, try to pinpoint where the smell is coming from. Use your nose. If it is gas, it usually would be from a leak in a pipe fitting or at the equipment itself. If the smell is coming out of the vents, it usually isn't gas. Sometimes dust that settles on the heat exchanger during the summer months burns off the beginning of each heating season and it smell just like gas.
If you can't locate the source of the odor and you are worried you have a gas leak, call the Gas Company and open your windows.
The oil leak is usually easy to spot. Just look for oil. Check the burner itself, the oil tank, filter and oil line. Sometimes it is just a matter of tightening a fitting. If there are no signs of an oil leak then it is most likely a burner problem.
This can be caused by many things, too many to list. It could be a minor adjustment to the burner to a faulty or blocked chimney. From a bad fuel pump to a plugged oil nozzle. Listen for any unusual rumbling or banging sounds or smoke or soot while the burner is running. If you notice any of these things and/or you have an oil odor, you should just call for service.
One other common problem today is that new houses are insulated so well that they run out of combustion air causing odor problems. In this case it is just a matter of bringing in a little fresh air.
But this odor problem is almost never due to a problem with your equipment.
Keep in mind that almost all heating systems cause an odor the first time they are fired-up. And the first few times at the beginning of each heating season. Brand new furnaces are coated with oil to keep the heat exchangers from rusting. This burns off, creating a bad odor - even smoke. But it usually only lasts for about 20 minutes. Opening the windows usually solves the problem. And the first few times the backup heat on a heat pump kicks on, it smells like an electrical smell. This might last for a few days but isn't that bad. If you are worried, call for service.
Remember to check for a clean air filter and that your vents are opened. Check to see if the fan is working which mean your motor hasn't burned-up.
Check for air leaks in damp areas, oil stains or rumbling sounds, strong gas odors - these all indicate problems. Do not ignore them.