Other items on the list of things to check for before you call a service person include checking your filter and making sure the fan on the outside unit is not obstructed. A dirty or clogged filter can often cause a heating or cooling system to freeze up. If the filter is dirty you should first try replacing or cleaning it if it is a permanent filter. If the clean filter does not correct the problem, it is probable that a fan or motor has burned out and will need to be repaired or replaced by a professional heating and air technician. If this is not the problem, the next thing to check is the outdoor portion of the unit. Leaves, twigs, and other debris often get trapped in the fan and keep it from functioning properly. Be sure to disconnect the electrical source to the unit before reaching inside or touching any parts.
You should also check to make sure the electrical connection on the outside unit is in place and working. If a technician has been there and cleaned the system, he or she may not have plugged it back in. This connection also sometimes wiggles loose on its own, says Floridia.
Dirty coils are another common cause of heating and cooling malfunctions. Floridia recommends having a professional clean your system's coils because they are very delicate and require special care. She says the worst thing a person can do is try to clean the coils with a wire brush. This can pull the coils out of alignment and also destroy the protective coating on them that prevents rust and decay. Professional technicians use special tools and chemicals for cleaning these coils. Floridia recommends having your heating and cooling system inspected twice a year, which includes cleaning the coils and other parts of the unit and checking for any leaks or safety concerns. Do-it-yourselfers can aid in the maintenance of their system by carefully vacuuming the inside of the outdoor unit occasionally, but should only do this to supplement regular maintenance inspections and not in place of professional cleaning.
Another common problem with heating and cooling systems is a lack of sufficient Freon or refrigerant. Floridia says the repair or replacement of anything involving Freon or refrigerant should definitely be left up to the professionals since they are trained to detect and repair leaks of this hazardous chemical. This product is now being phased out and replaced by the more environmentally friendly Puron, but should still only be replaced by professionals.
