No Heat

No Heat From Gas Furnace

If you notice your gas furnace is not providing heat, chances are pretty good you will need the assistance of a professional service technician. There are some common problems however, that you should be aware of before calling.

It is important to know what type of gas furnace that you have. Even though there are many types of gas furnaces in operation, let's focus on the two most common types that are out there. Chimney vented. Power vented.

If your gas furnace is vented to the chimney through a metal "stove Pipe", it is probably safe to assume your furnace has a standing pilot burner. Although some newer mid-efficiency furnaces are vented to a chimney and have some type of electronic ignition system. Below is a partial list of causes. Some will require a service call.

• Thermostat not turned to heat and/or set above the current temperature.
• Blown fuses or tripped circuit breaker
• Emergency power switch turned off
• Faulty thermostat
• Dirty filter
• Pilot light is out
• Faulty thermocouple
• Faulty or tight blower motor
• Faulty plenum switch or fan relay
• Faulty gas valve
• Blocked or restricted chimney or vent
• Open limit switch (plenum or exhaust)

If your gas furnace is vented through PVC pipes (high efficiency, condensing) It may have a self-diagnostic feature. If a no heat situation occurs and your furnace has a red light that is normally on steady but is now blinking, your furnace is trying to communicate a problem that may need corrected. Below is a partial list of causes. Some will require a service call.

• Thermostat not turned to heat and/or set above the current temperature.
• Blown fuses or tripped circuit breaker
• Emergency power switch turned off
• Faulty thermostat
• Dirty filter
• Faulty hot surface igniter
• Faulty spark igniter
• Faulty or tight blower motor
• Faulty plenum switch or fan relay
• Faulty gas valve
• Blocked or restricted PVC vent (check for snow or leaves where pipes exit the house)
• Blocked or restricted PVC intake (check for snow or leaves where pipes exit the house)
• Open limit switch (plenum or exhaust)
• Faulty pressure switch
• Blower door is off or not in place properly (from cleaning the filter)

No Heat From Oil Furnace

If your oil burner stops running the first thing you should check is the reset button. Usually a red button located on top of the burner. If you press it and the burner fires up then that was the problem. If the button should trip again you should schedule a service call . Do not keep resetting the button.

The button is part of a safety device. It shuts the burner down when it thinks there is a problem. It is on the primary control or cad cell relay.

On a call for heat, with the burner running, the cad cell senses the light of the flame. If it stops sensing the light, it causes the red button to pop up, shutting down the burner before any significant damage is done. Here is a partial list of causes and things to check. Most will require a service call and/or a cleaning.

• Bad or dirty cad cell
• Bad primary control
• Bad ignition transformer
• Bad burner motor
• Bad fuel pump
• Blocked oil filter or nozzle
• Air in oil line
• Burner running with a very high smoke level
• Burner sooted-up
• Out of oil
• Chimney blocked