A fireplace, stove, fireplace insert, or pellet stove offers ambiance and heat. This Fix-It Guide on fireplace and stove repair tells how a fireplace or stove works, what often goes wrong, how to identify a fireplace or stove problem, and what parts and tools you will need to fix it. It then gives instructions for how to sweep a chimney, how to install air vents in a wood floor or subfloor, how to replace a corroded stove connector, how to replace a door gasket, how to check and replace igniters on a gas fireplace or stove, how to clean a gas fireplace or stove pilot light, and how to adjust the pilot height. You may need to refer to masonry repair, appliance controls repair, or motor repair.
How Does a Fireplace or Stove Work?
An open wood fireplace consists of a hearth where wood is burned for heat and a chimney flue for expelling the smoke. Because heat can be lost with the smoke, a fireplace insert is often installed to increase heat retention. A freestanding wood stove, pellet stove, and gas stove also decorates and warms a home and requires some of the same maintenance and repair as a fireplace. (The terms “stove” and “fireplace” typically are used interchangeably.)
All fireplaces have the same two requirements: regulated air to feed the fire and a means of expelling smoke and fumes. A shuttered damper in the chimney provides an exit for smoke as well as creates an updraft that draws fresh air to the fire. Many new fireplace designs also use outside air intake vents under the fireplace so as not to draw warm air from the room. Gas fireplaces often have an inlet/outlet vent that expels fumes through a duct in an outside wall while drawing in fresh air.
Pellet stoves burn pellets made from sawdust and mill shavings; the pellets are loaded into a hopper at the top or front of the stove and delivered to the combustion chamber at a controlled rate by a motorized auger. Combustion air, blown into the chamber, develops superheated air. Room air is drawn across the heat exchanger by a fan, heated, and then returned to the room. Residual combustion gasses are vented outside, normally through a 3-inch flue that exits out the unit’s back or top.
Creosote, a by-product of burning wood, isn’t the problem it used to be because today’s fireplaces and wood stoves are much more efficient and burn hotter, which decreases the amount of creosote produced. As a result, creosote may not get a chance to build up inside and become a fire hazard. Even so, inspect your fireplace and chimney at least once a year for a flaky black creosote buildup.
What Can Go Wrong with a Fireplace or Stove?
A chimney will need cleaning. A fire may burn poorly and send smoke back into the room. A stove’s door gasket may wear out or come loose. A stove connector may corrode. Bricks or mortar may be damaged. The igniter of a gas stove may fail.
Make a bed for a better fire. Keep a half-inch bed of ash in the fireplace after cleaning as an insulator to prevent heat from being absorbed into the hearth.
How Can I Identify a Fireplace or Stove Problem?
- If a fire burns poorly and sends smoke back into the room, make sure the damper is fully open. Verify that the chimney is clean and free of obstructions (see below). In addition, you can have a wind cap or chimney cap installed or you can install air vents in the floor on either side of the fireplace (see below).
- If a stove connector is corroded, you can replace it (see below).
- If fireplace bricks or mortar are damaged, you can repair them using a 1 to 3 mix of fireclay cement and sand (see the Masonry Fix-It Guide).
- If a gas stove will not ignite, you can replace the igniter (see below) and adjust the pilot (see below).
- If a pellet stove will not feed pellets, check the controls (see the Appliance Controls Fix-It Guide) and the motor (see the Motor Fix-It Guide).
Install a carbon monoxide detector in a room with a fireplace to alert you to a buildup of carbon monoxide that might be caused by a downdraft or a plugged-up chimney.
What Do I Need for Fireplace or Stove Repair?
- High-temperature sealant
- Measuring tape
- Electric drill
- Metal snips
- Crimping tool
- Chimney brushes
- Shop (not household) vacuum cleaner
- Duct tape
- Sewing needle
- Self-tapping sheet-metal screws
- Dropcloth or other heavy cloth
What Are the Steps to Fireplace or Stove Repair?
Sweep a fireplace or stove chimney:
- Remove all loose items from the fire surround and the hearth.
- Cover the fireplace opening with a heavy fabric cover and seal it with duct tape. Also cover nearby flooring and furniture with a dropcloth.
- From atop the roof, push a chimney brush from the chimney top down toward the fireplace below, moving the brush up and down to loosen debris.
- Continue pushing the brush down the chimney by adding extension canes and moving the brush to loosen debris.
- When the brush reaches the bottom of the chimney, withdraw the brush.
- Allow the dust to settle for at least one hour before removing the cover over the fireplace opening.
- Use a shop vacuum cleaner to remove debris from the fireplace floor and the smoke shelf.
Install air vents in a wood floor or subfloor:
- Visit a fireplace shop or department of a large building materials store for advice on what vents should be installed and where.
- Measure the opening needed for the vents you have chosen, and mark it with a pencil.
- Drill a hole in one corner of the opening.
- Use a jigsaw to cut the perimeter of the hole.
- Install the vent following the manufacturer’s recommendations. Many vents are held in place by their own weight and don’t require fasteners.
Replace a corroded stove connector:
- Inspect and measure the pipe and connector to be replaced. Use these measurements to purchase replacement stovepipe, connectors, and other needed materials.
- Remove fasteners holding the stovepipe, collar, joints, and flue connection.
- Disassemble the connector, being careful not to disturb soot that can become airborne.
- Reassemble the connector, using replacement components as needed.
- As needed, secure all joints with self-tapping 1/4-inch sheet-metal screws.
Replace a fireplace or stove door gasket:
- Remove the old gasket from the door, starting at the seam.
- Clean the gasket channel of old sealant using a screwdriver.
- Apply high-temperature sealant around the gasket channel.
- Press the new gasket firmly into the sealant bed and trim the end of the gasket to fit tightly.
- Close and tightly latch the door for 24 to 48 hours or as recommended by the sealant manufacturer to allow for complete drying.
Check and replace igniters on a gas fireplace or stove:
- Turn off the gas shutoff valve.
- Trace the igniter cable to a terminal on the ignition control module at the back of the stove.
- Remove the cover and disconnect the igniter cable.
- Replace the igniter with a duplicate.
Clean a gas pilot light on a gas fireplace or stove:
- Turn off the gas shutoff valve to the gas fireplace or stove.
- Remove the metal shield covering the pilot light.
- Use a sewing needle to carefully remove debris in the pilot opening, blowing away any loose debris.
- Turn the gas shutoff valve on and test the gas pilot light.
Adjust the pilot height on a gas fireplace or stove:
- Turn off the gas shutoff valve to the gas stove.
- Locate the pilot adjustment screw on the side of the pilot, on the pilot gas line, or behind the control knob.
- Turn the screw counterclockwise to increase the size of the pilot. The flame should be a sharp, blue cone, about 1/4 to 3/8 inch high.
pending on what type and how much fuel you burn in a fireplace, have the chimney and flue inspected regularly by a professional. The CSIA (Chimney Safety Institute of America) certifies chimney sweeps who can clean a chimney and perform a general structural inspection.