When a heating or cooling system malfunctions, any one of its three components — heat/cold source, distribution system, or thermostat — may be causing the problem. If the furnace or air conditioner doesn’t run, the malfunction is probably at the source. The furnace or air conditioner may have lost power. Fuel may not be reaching the unit. If the fuel is gas or oil, it may not be igniting. If the furnace or air conditioner turns on but the warm or cool air isn’t reaching the rooms of your home, the problem is likely to be the blower or distribution system. And a faulty control, or thermostat, could keep the system from turning on or could cause it to turn on and off repeatedly. Whatever the problem, start with the simplest procedures. In most cases, all it takes is patience and common sense.

Before you start work on a heating or cooling system, take these preliminary steps:

• Make sure the unit is receiving power. Look for blown fuses or tripped circuit breakers at the main entrance panel. Some furnaces have a separate power entrance, usually located at a different panel near the main entrance panel. Some furnaces have fuses mounted in or on the unit.
• If the unit has a reset button, marked reset and near the motor housing, wait 30 minutes to let the motor cool, then press the button.
• If the unit still doesn’t start, wait 30 minutes and press the reset button again. Repeat at least once more.
• If the unit has a separate power switch, make sure the switch is turned on.
• Check to make sure the thermostat is properly set. If necessary, raise (or, for an air conditioner, lower) the setting 5 degrees.
• If the unit uses gas, check to make sure the gas supply is turned on and the pilot light is lit. If it uses oil, check to make sure there is an adequate supply of oil.

The very best idea for central heating maintenance in San Mateo is to have a service professional out to give your system a checkup. Our Peninsula and South Bay Area air conditioning and heating contractors regularly handle these exact tasks, and they can provide you with a thorough check of your heating system and ensure that it will run effectively all winter.