Gas Appliances & Masonry Chimney Safety
What to consider with Natural Gas Appliances
Propane and Natural gas heating appliances have become a very popular way to heat homes. Every homeowner must take the proper steps to ensure their chimney and appliances are running efficiently. Chimney inspection should be performed only by a CSIA Certified Chimney Sweep on an annual basis.
If your home already has a gas-heating appliance which uses a masonry chimney as a venting system and you have not had it checked for signs of wear, we suggest making an appointment to do so. Older chimneys are usually suspect to wear and tear and should always be carefully evaluated before installing a newer high efficiency gas furnace or boiler. This is especially important with appliances that are more than 80% efficient.
Appliances fueled by natural gas or propane usually do not produce visible soot that other fuels do, but they do deposit corrosive substances on the inside of your chimney. Unfortunately, the acid wreaks havoc on your chimney often without showing any external symptoms until the problem has become dangerous and very costly to repair. When masonry deteriorates it often cause blockages within the flue. A blocked flue could damage your heating appliance, and/or cause a house fire. Another often deadly result of blockages in chimneys is carbon monoxide poisoning.
More information on carbon monoxide poisoning
Proper venting in a masonry chimney
When a gas appliance uses your chimney as a venting system, the heating and venting must be properly matched in order to achieve the safest and most efficient operation. Improper matches often occur when flues or connector pipes are too large or too small.
When your system is properly matched, it ensures your appliance will run efficiently and safely and thus ensure a longer lifespan of your chimney and the appliance/s. When systems are not properly matched bad things can happen. Old chimneys and new gas appliances usually do not work well together because they were not designed for each other. Older chimneys were designed for older and more inefficient heating appliances which kept the chimney very warm and “dry”. Newer heating appliances are designed to keep more heat in your home and to not waste it by sending it up the chimney flue. A common result of this change in technology is lower exhaust temperatures and excess moisture within the chimney flue. This moisture is the result of exhaust cooling as it travels up the flue. Once the exhaust reaches 135 degrees Fahrenheit or cooler it condenses as water vapor. These circumstances lead to faster deterioration within the chimney. This is especially so with chimneys which are located on “colder” exterior walls. Older masonry chimneys can usually be updated to work with newer more efficient gas appliances.
Which gas heating appliance chimneys should I have checked?
– gas furnace
– gas boiler
– gas water heater
– gas heater insert
What signs indicate a problem with your gas heating unit ?
Many signs are not apparent from the outside of your chimney, though some visible moisture issues from improper venting can arise. Things to look out for are:
- Noticeable dampness on interior or exterior walls
- Peeling patches of wallpaper
- Blistering paint
- Visible stains on the ceiling
- White colored stains called efflorescence which appear on the outside masonry of the chimney
- Eroding mortar joints
- Crumbling bricks
- The Carbon monoxide alarm goes off
Believe it or not there is a lot more that we consider when we are trouble shooting and inspecting chimney issues. If you have an older chimney, or, if you suspect that your chimney is unsafe, call us. We can help.