Upgrading is Shrewd
Many homeowners are replacing old appliances with newer energy-efficient ones – whether that be a furnace, water heater or firebox. Any upgrades should prompt attention to the ventilation system in your home. Your furnace, boiler, water heater and fireplace all vent through the chimney. To keep your ventilation system working properly with new appliances, you have to confirm that air is safely and efficiently making its way out. This could require a chimney liner. It also means you’ll need to have your vents inspected.
Code Concerns – An Introduction
Interestingly, Google very quickly defines “firebox” as “the chamber of a…boiler in which (its) fuel is burned”. Its rapid definition also shows “firebox” to be synonymous with “fireplace” and “furnace”. That is because all of them contain a firebox – which causes them to be used interchangeably to some extent.
All good, but to explain why upgrades raise safety concerns when ‘other fireboxes’ are installed, we need first to agree on language. For the purposes of this discussion, a firebox is the chamber of any combustion appliance. A “boiler” is a boiler, a “furnace” is a furnace, and a “fireplace” is a firebox because we are talking about combustion appliances. We are also talking to people with masonry chimneys, which used to provide venting for different fireboxes.
What Came Before…
Homeowners who choose energy-efficient appliances are smart; they save resources, both their own and those of our Planet’s. Most are not, however, specially trained appliance technicians themselves and logically, do not have any reason to think about the old appliances or the vents that accompanied them.
Far too often, the vents are forgotten when they are “orphaned” by the replacement of your old appliances. The “orphaned vent” is what causes the inefficiency of your brand new “efficient firebox”. The ‘orphan’ is still there, and so a chimney flue that is now too big, vents your other gas appliances. When that flue was put above your masonry fireplace, the chimney liner was designed for the inefficiency of old fireboxes.
Whichever appliance ‘parented’ the orphaned vent, the chimney continues to work as if the orphaned firebox is still married to it. As a result, the surviving appliances are vented through a flue that is now too big to achieve the same up-and-out draft. There goes your efficiency — and in come the inspectors, because that situation compromises your safety. Because the cooler “more efficient” flue gas from your new firebox stays in the now-too-big fireplace flue longer with more moisture in it, they call it “a change of use” for your old chimney.
What Can Happen With Neglect
If the changes to your ventilation system are not upgraded along with your appliances, this can lead to an over-sized flue. There are two main dangers; carbon monoxide poisoning and excessive condensation. Each year over 400 Americans die from carbon monoxide poisoning. This odorless, tasteless gas can be generated from incomplete combustion. The other peril is condensation buildup. This can cause cosmetic, as well as structural damage to your chimney. This can result in the crumbling of your liner, mortar and brickwork.
Symptoms of possible problems:
- Damp patches on interior walls or exterior walls
- Peeling wallpaper
- Blistered paint
- Stains on the ceiling around the chimney
- White stains on the outside of the masonry chimney
- Eroded mortar joints
- Decaying bricks
– See more here.
Here is the bottom line: service by a professional chimney sweep can identify, fix and prevent many of these problems. The risks of doing nothing or trying to do this yourself are just not worth it. Getting greener appliances is the way to go, but homeowners have to put the same kind of care to making sure those appliances have suitable ventilation.