[PDF] Berkshire Owner’s Manual - Kirkland Fireplace (propane). If the label is absent, the heater is equipped for NG (natural gas). • This heater is either approved for natural gas (NG) or for propane (LP or LPG). Burning the incorrect fuel will void the warranty and safety listing and may cause an extreme safety hazard. Direct questions about the type of fuel used to your dealer. Fireplace Installation + Owners Manual Downloads | Heatilator Gas and wood burning fireplaces have a rating plate in the control compartment area, under the smoke shield or on the firebox side column. Gas and wood burning inserts have a rating plate in the control compartment area, under the ash lip or on the firebox side. The rating plate for an electric fireplace is located on the firebox ceiling.