The Mason-Lite Combustion Air Kit - 4" will provide enough replacement air in order for your masonry fireplace to function properly. The kit will also meet some local building codes that may require outside combustion air to be provided. If no replacement air is provided to the fireplace, improper flue drafting may occur, creating negative pressure whereby smoke may enter the home, especially in homes that are very well insulated and tightly sealed.

The Mason-Lite Combustion Air Kit - 4" will install through the side wall opening provided. A 4” diameter hole will also be required through the firebrick side lining. The tubing that goes out of the firebox wall must feed into a flexible metal conduit as the source for outside combustible air. It can go straight out through an outside wall or into a ventilated crawl space. If crawl space is used, check codes for proper termination.

Features:

• Designed for 4 inch diameter
• 3' flexible vent included
• Plastic hood included for installation