Chimneys serving fireplaces, water heaters, boilers, furnaces, and other fuel-burning appliances deteriorate over time. The mortar in the joints crumbles and falls out, the brickwork cracks and crumbles away, the flues crack and the dampers and other ironwork deteriorate from the highly corrosive fumes of combustion. So, when adding, repairing, or replacing any fuel-burning appliance that is connected to your existing chimney, a close inspection is called for. It is costly and difficult to repair many of these chimney defects. The prospect of tearing down and rebuilding a brick or stone chimney is a daunting task for most homeowners.
Fortunately, there is a solution to this dilemma. Install a chimney liner. Many local codes require a chimney liner to be installed whenever any work is done to the existing chimney anyway, such as adding or replacing a fuel-burning appliance to it.
- First, clean your existing chimney. Use a chimney sweep or purchase the correct size and shape of brushes and rod extensions and scrub the walls of your chimney to eliminate as much creosote and soot as possible.
- Inspect the interior of your entire chimney including the smoke shelf, the damper, and the ash pit, if there is one. Use a strong drop light and lower it into the chimney. Make sure you note the location of any serious defects like missing brick, broken flue blocks, etc.
- In some appliance installations, you may have to remove the chimney damper. Usually, you just reach up inside the chimney, grasp one end of the damper and lift it up. Then slant the damper out of its supports and pull it straight down.
Install the chimney liner
- Attach a rope to the lower end of the new chimney liner.
- Lower the rope down the chimney.
- Have a helper at the lower end of the chimney. They should reach in the chimney through a hole prepared for a new connection and grasp the rope.
- As you lower the chimney liner down the chimney, the helper will retrieve it by guiding it with the rope until the end of the new chimney liner exits the chimney.
- Be careful as you lower the liner that it does not catch on any projections inside the chimney.
- You may have to twist the liner gently to help it move down past the smoke shelf inside the chimney.
- In some cases, the helper may have to reach up inside the chimney to grasp the lower end of the liner and maneuver it past the smoke shelf.
- Once you have the liner installed in the chimney to the proper depth, install the vent termination on top of the chimney.
- Be sure to fasten the vent termination to the chimney and caulk it well with a good quality silicone caulk.
- Return to the lower end of the chimney and attach the chimney liner to the appliance. Then continue the appliance installation according to the manufacturer’s instructions.
In cases where you are attaching a chimney liner to an appliance such as a water heater, the liner will exit the chimney. Be sure to seal that hole with a flashing or chimney cement.
Be careful to install the correct size chimney liner to serve all appliances connected to the chimney. Consult appropriate mechanical codes or your local building code department for the correct sizing information.
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