Troubleshooting Oil Furnaces and Air Conditioning

Having trouble with your heating or cooling system?  Many solutions are a quick and simple fix that you can handle safely and easily yourself.  Check out the basic troubleshooting tips below.  If one or more of these suggestions doesn’t do the trick, Superior will be happy to schedule a service appointment at your soonest possible convenience, or provide emergency repair services if necessary. Just call 508-865-1972.

Oil Furnace Basic Troubleshooting

• First check that the thermostat is set higher than the actual room temperature. If you have a programmable thermostat, check that it has fresh batteries.
• If equipped with central air, or the system is zoned, make certain the selector switch is on heat.
• Check that the emergency switch (usually a red switch plate at the top of the cellar stairs or on the side of the furnace) is on.
• If you are familiar with the fuse or circuit breaker panel, see if the fuse is burned or the breaker is tripped. Correct the problem once; if the fuse blows or breaker trips again, call a serviceman.
• If you can access the burner, check the red button on the protector relay. Older furnaces will have a stack limit switch mounted on the smoke pipe that connects the furnace to the chimney. Push the button one time only. Repeated attempts to fire the burner without ignition can create an explosive condition. If the burner fails to fire and continue running on its own, call for service.

• First make sure that the thermostat is set lower than the actual room temperature. The selector switch must be on "cool". If the thermostat is programmable, be certain it has fresh batteries.
• Check for power by moving the fan switch from "auto" to "on". If the blower runs, there is power. If nothing happens, a control is burned out or power is disconnected. If the system uses a furnace for heat, check that the emergency switch is on. If you are familiar with the fuse or circuit breaker panel, check for blown fuses or tripped breakers. Correct the problem one time only. If it repeats, call for service.
• With the selector switch on cool and the fan switch on auto, move the thermostat well below room temperature. If the blower runs but the condenser (outdoor unit) does not, check the circuit breaker panel. If the breaker is on, examine the condenser.  Some have a high pressure cut out. It is a button sticking out of the cabinet, usually near the refrigerant lines. Push it in as far as it will go to reset it.
• If both units are running and no cooling is taking place, touch the larger of the two copper lines exiting the condenser. If it is warm, the system is out of freon or the compressor is down. If the line is frozen or iced over, there is an air flow problem inside, such as clogged filter or too many registers closed or an object covering the return duct. A low freon charge will also cause a freeze-up. Shut the system down and let it thaw out completely. If it freezes up again, call for service.
• If the unit is in the basement and has a condensate pump, the control wire for the condenser might be wired through a safety switch on the pump. Check to see if the pump is plugged in and operable. If the unit is in the attic, there could be a float switch in the air handler or in the safety pan that will shut the condenser off if the drain is clogged. Water around the unit is evidence of trouble. Call for service.