A message from the Garrison Petawawa Fire Prevention Branch


Posted on Thursday, March 21, 2019

Snow fall and your furnace “IMPORTANT NOTICE”

There are several parts of the country that are currently rolling up their sleeves and shoveling their driveways. When snow falls in such large quantities we begin to worry about the safety and comfort of our homes. We rely on them to protect us from harsh weather conditions, and the furnace plays a key role in this protection. However, the snow can interfere with the furnace and create a hazard or at least some discomfort if you do not take the proper steps to prevent this from happening.

Blocked PVC
Exhaust Pipes

Modern forced air furnaces do not exhaust through the chimney. Instead, they have PVC lines that exit through the side of the home. This is a more efficient way of releasing exhaust from the system and is part of the reason that the unit is able to maintain such a high AFUE rating. However, if this PVC line becomes blocked by snow, one of two things can happen:

• Partial Blockage: If snow drifts only cover up part of the PVC pipe, odds are the system will continue to work, but the exhaust could begin to backup into the home. Along with other harmful gases, that exhaust contains carbon monoxide. Carbon monoxide buildup in the home can make your family sick and cause deaths if levels are allowed to rise high enough.

• Complete Blockage: If the snow covers PVC opening completely, odds are the furnace will stop working all together. The unit will overheat and shut itself off as a safety mechanism to prevent damage. You could spend hundreds of dollars on an unnecessary service call if this happens to your home, but it can be prevented.

Carbon Monoxide
Carbon monoxide is a gas. You cannot see it, taste it, or smell it. It is created when fuels do not burn completely. Kerosene, gasoline, coal, natural gas, propane, and wood are examples of fuels. Carbon monoxide can make you very    sick or kill you. You need a carbon monoxide alarm on each level of your home. If you hear the carbon monoxide alarm, get outside the home right away. Call for help from outside.

Clear Away the Snow
After heavy snowfall, be sure to check the PVC pipe religiously.

You can fix the overheating problem if you clear away the snow and restart the system, and you won’t risk exposure to carbon monoxide if you get into this habit as well. Clear away any snow before allowing the furnace to run, and you will prevent these problems from occurring in your home after major snow storms.