Venting system for a gas-fired heating plant

Claim 1

In combination with a gas-fired heating plant having a base, an upper portion and having a combustion chamber provided with a flue outlet disposed in the upper portion for the outlet passage of combustion gases to be conveyed to a chimney flue for the heating plant: a venting system for the combustion chamber comprising a first piping connected to the flue outlet, a second piping connected to the chimney flue, an elongate diverter box vertically positioned on the heating plant exteriorly thereof and having a first and second set of opposing vertical walls and having an upper portion with a top wall and a lower portion, said diverter box being connected to and intercommunicating both of said pipings at its upper portion which has opposing openings in one set of opposing vertical walls to accommodate the pipings, said diverter box having a bottom in its lower portion provided with a substantial opening disposed well above the base of the heating plant with said opening being in constant free communication with the atmospheric air surrounding the heating plant which air enters the diverter box through the opening in the bottom as cold air to establish a cold air pressure head below the first piping and establish a heat lock to prevent the flow of heated air from the combustion chamber outlet of the heating plant and also to prevent down drafts from the chimney flue attempting to pass down through the second piping from reaching the combustion chamber of the heating plant, and said diverter box having a heat resistant baffle plate disposed vertically thereof midway between the opposing vertical walls to which the pipings are connected.