In order to manually light a gas fireplace, make sure the damper is open and slowly turn on the gas when it’s moving over the lighter or matches. Discover why a gas fireplace should never be turned on ahead of time with help from a home remodeling specialist in this free video on gas fireplaces. Expert: William Perkinson Bio: William Perkinson is a partner with Perkinson Building Corporation, based in Birmingham, Ala. Filmmaker: Tim Brown