Boiler & Furnace Relining For A Safer, More Efficiently Heated Home

Natural gas has become a very popular fuel choice for boilers and furnaces because it provides an economical, clean, and convenient way to heat the home. But just like the chimney that vents your fireplace or stove, the chimney attached to your boiler or furnace needs to be properly sized and in peak condition in order to safely and effectively vent the appliance.

Modern mid to high efficiency boilers and furnaces can be especially hard on their liners because the amount of condensation that’s produced is directly related to efficiency. Most gas furnaces and boilers sit at the 80% efficiency level, and create large amounts of condensation and water vapor. While the exhaust gases don’t hit the dew point and become water vapor inside of the appliance, they do once they’re in the venting system. That’s where trouble starts.

Due to chlorides in the combustion air drawn into the furnace or boiler, the condensation and water vapor produced can be highly acidic, which makes matters worse for the liner. Over time, what happens is that this corrosive condensate corrodes areas of the liner, leaving the entire furnace/boiler system unsafe and inefficient.

The liner itself isn’t the only thing threatened by the condensation produced. The masonry surrounding the flue can also rapidly deteriorate once it comes into contact with this moisture, as a result of the freeze/thaw process. As the flue gases cool on the surface of the brick and mortar, they can lead to:

  • spalling/flaking bricks
  • mildew/moss growth
  • white efflorescence stains
  • leaks/water stains surrounding the chimney

Why Do Boiler/Furnace Chimneys Need To Be Relined?

Aside from corrosion and damage to the flue liner, why else would you need to have your boiler or furnace flue relined?

Safety, Draft & Efficiency

Earlier we brushed on the fact that the chimney venting the gas appliance must be appropriately sized in order to work properly. If the chimney flue is too large for the gas furnace or boiler, the exhaust gases produced will rapidly cool inside the chimney.

As we all know, hot air rises, but cool air does not. Without the heat necessary to achieve good draft, these flue gases will remain in the chimney longer, which increases the likelihood that your family will be exposed to the dangers of carbon monoxide. This colorless, odorless, tasteless, and invisible gas can cause a host of health problems, and in large doses, can even be fatal.

Liner problems and poor draft don’t just increase your risk of carbon monoxide exposure, they also decrease appliance efficiency. Fuel will burn incompletely, efficiency ratings will suffer, and you won’t get the performance you expect out of your boiler or furnace. Proper draft is vital to the performance and safety of the entire system.

What Materials Are Used For Relining?

Because of the corrosive nature of the exhaust produced by newer gas furnaces/boilers, not just any material can be used to reline the flue. Aluminum isn’t even an option, as it will quickly corrode. Even traditional stainless steel won’t last long with modern gas appliances, which is why we solely reline with American-made 316Ti austenitic stainless steel alloy liners and AL 29-4C ferritic stainless steel liners:

  • 316Ti Austenitic Stainless Steel Alloy — This titanium-stabilized steel offers far greater corrosion resistance, strength, and durability than other stainless options, and is able to provide years and years of service. Welded and seamless, a 316Ti stainless steel alloy liner will keep your furnace/boiler working efficiently and safely, without caving to corrosion.
  • AL 29-4C Ferritic Stainless Steel — This tough, welded gas liner is able to resist some of the most common types of liner damage, including corrosion, cracking, chloride ion pitting, and other damage that occurs due to stress, heat, and moisture. Like 316Ti liners, AL 29-4C liners are guaranteed to last so you can enjoy a safer, more efficient home heating experience.

Both liners are lightweight, strong, water/vapor tight, and built to last, and each carries a lifetime warranty when professionally installed and annually inspected by a CSIA certified chimney sweep.

Why Boiler Liners Should Be Insulated

The manufacturers of our liners always recommend that the liners be properly insulated, and not just for safety reasons. By insulating the liner, we’re able to increase draft and help achieve the highest level of efficiency. Insulated liners warm up faster, which means more heat for your home and better performance from your boiler. It also means less condensation, less opportunity for moisture damage to occur, and a longer-lasting boiler to keep you and your family warm for decades. Insulation is a crucial part of boiler/furnace flue relining and it’s not a step we skip!

Call Today To Request An Appointment With An Experienced Relining Professional

Is it time to have your furnace/boiler flue relined so you can enjoy a safer, more efficient system? Call The Chimney Doctor at 970-234-3330 or request a furnace/boiler flue inspection and relining appointment right here on our website. We’re happy to help — it’s what we do!