Things You'll Need

Instructions

1

Look for rust or flame marks displayed on the oil furnace. Also check for signs of cracks and perforations caused by rust. This could be an indication of damage on the heat exchanger and could possible result in a leak of carbon monoxide.
2

Inspect for discoloration on the heat exchanger or cracks in the steel or soot. Use a flashlight to closely and clearly inspect the entire area of the furnace.
3

Turn off the burner and inspect the top of the burner for cracks, rust and discoloration.
4

Use a telescoping mirror to inspect in and around tricky areas that are hard to access or reach.
5

Inspect the surrounding area and determine whether the furnace is exposed to wet conditions, for example, if it is located in close proximity to a plumbing system with a leak or a condensate leak resulting from an air conditioning unit. These systems contain water and can leak that water into the exchanger and cause it to rust.
6

Install a carbon monoxide alarm that will alert you to the present of carbon monoxide. If your furnace is releasing carbon monoxide into your home, the alarm will pick up on this and sound to alert you.
7

Consult a furnace manufacturer to perform an inspection of the heating equipment. This should be done at least once per year. The manufacturer checks the condition of the furnace heat exchanger and cleans out the cavity to remove a buildup of soot. This can be difficult to reach and do yourself. Technicians will also clean or replace the air filter if necessary and check the oil pressure in the burner and test the safety features, such as the high limit control.
8

Use a probe-type metal thermometer to measure the temperature of the flue gas. It should be between 350 and 540 degrees Fahrenheit. The lower the number the better; if it gets higher than this, you should consult the manufacturer right away.
9

Drill a hole into the flue pipe, about 15 inches from the furnace exit. Insert the flue pipe thermometer probe. You can leave the thermometer in there permanently, if you wish. Clean away any sooty buildup when you remove the thermometer, as it could affect the reading the next time you use it.
10

Turn the thermostat up as high as it can go and let it idle for about 15 minutes. Read the temperature on the thermometer and turn down the thermostat. If it has changed, for example, a three percent drop, it could indicate that the air filter needs to be replaced. This is when you need to notify the manufacturer.