Holes & Cracks in an Oil Furnace

Heat Exchanger

• Heat exchangers are the core of the furnace and, when cracks appear in them, it often means you need to purchase a new furnace. Heat exchangers usually last between 15 and 20 years, but sometimes cracks appear prematurely. Look for cracks, discoloration and soot in the heat exchanger, and check for open seams or leaks in the gaskets or sealants. Holes may also appear when screws fall out. Although a visual inspection may reveal cracks, because 80 percent of the heat exchanger isn’t visible, most cracks are detected by other means, such as by using a flashlight and telescoping mirror or by having a technician run a pressure change or water spray test.

Combustion Chamber

• A telescoping mirror and flashlight should also be used to examine the combustion chamber for cracks and corrosion. The gaskets around the door to the combustion chamber should also be inspected, because they can crack over time, causing smoke and heat to escape into the house. Symptoms that your combustion chamber may be cracked include an oily smell in the house or the appearance of soot and smoke coming through the registers.

Venting

• Flue pipes can also develop cracks and holes, along with the furnace connections to those pipes. Corrosive gases that enter the chimney eat away at the liner over a period of years, causing cracks to appear. Look for small particles at the base of your masonry chimney. Metal chimneys are lined with stainless steel that can develop tiny pinholes when the acids in soot cause them to corrode. When this happens, you’ll need to reline your chimney.

Dangers

• Carbon monoxide is a colorless, odorless, toxic gas that’s a byproduct of combustion. Usually it’s vented out of your house, but it can leak into a building through cracks and holes in your heating system. Symptoms of carbon monoxide poisoning include headache, dizziness, nausea, vomiting, chest pain and confusion. Installing a carbon monoxide detector will help keep you safe. If your flu-like symptoms disappear when you leave home only to reappear when you return, leave your home immediately and have your furnace checked.