The damper in a fireplace is a critical component that regulates airflow between the firebox and the chimney. For fireplaces, particularly those used with gas logs or inserts, the damper is required to remain fixed open to ensure safe venting of combustion byproducts. If the damper is not properly fixed open, it can lead to serious safety hazards and operational issues. Below, we discuss the importance of fixing the damper open, potential risks, and how to address the issue.

A fireplace damper is a metal plate located at the base of the chimney, usually within the throat above the firebox. It can be opened or closed to regulate airflow:

• Open Position: Allows smoke, gas, and byproducts to escape through the chimney.

• Closed Position: Prevents heat loss when the fireplace is not in use.

1. Gas Logs and Inserts

• Unlike wood-burning fires, gas fireplaces produce consistent combustion byproducts, including carbon monoxide, that must vent safely.

• A fixed-open damper ensures continuous airflow to prevent dangerous gas buildup.

2. Ventilation Safety

• If the damper is closed or partially closed during operation, it can trap smoke, carbon monoxide, and other toxic gases inside the home.

3. Code Compliance

• Building codes typically require dampers to be fixed open when gas logs or inserts are installed to eliminate the risk of accidental closure.

1. Carbon Monoxide Poisoning

• Closed dampers can trap carbon monoxide, an odorless and potentially lethal gas, in the home.

2. Smoke and Odor Issues

• Improper venting can cause smoke and combustion odors to linger inside the house.

3. Fire Hazard

• Restricted airflow increases the risk of excessive heat buildup, which could ignite nearby materials.

4. Code Violations

• A non-fixed open damper may violate local building and safety codes, potentially affecting insurance coverage and property resale value.

1. Inspection

• Begin with a professional inspection by a certified chimney technician to assess the condition and functionality of the damper.

2. Fixing the Damper Open

• Clamp Installation: Install a damper clamp or locking device to hold the damper permanently in the open position. This is a simple, cost-effective solution often required for gas log installations.

• Mechanical Lock: In some cases, a mechanical fix or bolt may be added to ensure the damper remains open.

3. Replace or Upgrade the Damper

• If the existing damper is damaged or difficult to secure, consider replacing it with a new, code-compliant model or installing a vented cap on the chimney.

4. Gas Log or Insert Retrofit

• If your fireplace has been converted to gas, ensure that the damper modification was part of the installation. Retrofitting the damper with a clamp is a common and necessary step.

5. Consult Local Codes

• Verify that all damper modifications meet local building and safety code requirements.

1. Regular Inspections

• Schedule annual inspections to ensure the damper is functioning properly and remains fixed open for gas logs or inserts.

2. Proper Maintenance

• Clean the damper and chimney regularly to prevent obstructions or corrosion that could interfere with the damper’s operation.

3. Signage

• Place a visible tag or label near the fireplace indicating that the damper must remain open, especially for gas fireplaces.

4. Professional Installation

• Always hire a certified professional for gas log or insert installations to ensure all components, including the damper, are compliant with safety standards.

If your damper is not fixed open and you’re unsure how to address the issue, stop using the fireplace immediately and contact a certified chimney technician or gas fireplace installer. Operating a fireplace with a non-fixed open damper can result in serious safety hazards.

Fixing the damper open in a gas fireplace or insert is a critical safety measure that ensures proper venting of combustion byproducts. Addressing this issue promptly can prevent health risks, fire hazards, and code violations. For homeowners with wood-burning fireplaces, the damper’s position should still be carefully monitored and adjusted appropriately during and after use. Prioritize regular maintenance and inspections to keep your fireplace safe and functional for years to come.