Wood Heating in Your Home

Woodburning systems must operate under a variety of conditions during each heating season, and these different conditions create the need for a number of maintenance tasks. For example, the slower burning needed in fall and spring when heat demand is low, tends to result in more rapid creosote formation in the flue pipe and chimney. Chimney cleaning is usually needed more often in spring and fall. On the other hand, wood- burning appliances operate closer to their maximum heat output during the coldest winter months, creating stresses on internal components. Many of the modern wood heaters have internal components that can wear out because of their exposure to high temperatures. These components can be replaced.

One of the best ways to ensure that your wood heating system gets the maintenance it needs to be safe and effective is to hire a fully-trained professional chimney sweep. A professional sweep will clean the system top to bottom and report any problems to you. The sweep might suggest that it is time to replace the flue pipes, catalytic combustor, or door gaskets and will probably be able to do the work for you when the time comes. Your wood heating retailer may also offer sweeping and maintenance services.

Here are the most important maintenance tasks to consider as you look over the condition of your wood heating system:

Clean and inspect the chimney and flue pipes

The chimney and flue pipes must be checked regularly until rate of creosote build-up is determined. Chimney fires usually occur because the user was surprised at how fast the deposits developed. Check them often and clean when the deposits have built up to more than 4 mm (1/8"). Older systems, or ones that experience smoldering fires too often can need cleaning as often as every three weeks. Most modern systems operate so efficiently that cleaning is needed only once a year. Never assume the chimney is clean; check it often to be sure. During maintenance it is a good idea to check the condition of the chimney and flue pipes to determine if there has been any deterioration. Check the flue pipes for corrosion that can weaken the joints. Look for corrosion or rust stains on the outer shell of a metal chim- ney, and check for bulges or corrosion in its liner. When inspecting a masonry chimney, look for black or white stains on the outer bricks, and cracks or missing pieces in the chimney liner. Always check the condition of the chimney in hidden spaces including the attic, wall and chimney chase areas where corrosion and other deterioration can occur. The most thorough cleaning and inspection of the system should be done in the spring just after the heating season is over. If you leave deposits in the system, the warm humid summer air will cause corrosion of steel parts. Cleaning and inspection in spring will also give you plenty of time to order replacement parts and do any repairs that are necessary before the fall heating season begins. If you see any problems during your cleaning and inspection, have the system thoroughly inspected by a qualified chimney sweep and repaired before continuing to use it.

Replace door gaskets and other seals

These gaskets and seals are used by the appliance designer to control the location and flow rates of air into the appliance. Leaky seals will reduce the efficiency of the unit. Some gaskets may need replacement as often as once per year, and others may be fine for several years of use. All gaskets and seals should be checked at least once per year during a thorough maintenance check and perhaps once during the heating season.

Replace baffles or catalytic combustors

Components inside the combustion area of modern wood-burning appliances are exposed to extremely high temperatures and may deteriorate with use. Catalytic combustors and internal baffles may last as little as one year, or as many as four years, depending on how the appliance is used. If in doubt about when to replace these parts, check with your chimney sweep or wood heating appliance retailer.

Maintaining door glass

The door glass in modern wood burners is not glass at all, but a transparent ceramic material that can withstand very high temperatures. It is very unlikely that the 'glass' will break because of heat, but if it is struck with a hard object, it will break. Always go back to the store where you bought the appliance or to its manufacturer for replacement glass so you are sure to get the right size, shape and material. This ceramic glass will need cleaning at least every week or two. Wait until the appliance has cooled before cleaning the glass. Usually, a damp cloth or paper towel will remove the ash dust or light brown stains. For darker more stubborn stains, you can buy special stove glass cleaner that removes the stains easily and does not scratch the surface. Don't forget to replace the door glass gasket if it gets worn.