Table of Contents
Gas Manifolds - Furnace gas manifolds connect the valve to the main burners and it is important that the proper pressure be present inside the manifold for proper combustion. Manifold pressure is different from natural gas to liquid propane. Furthermore, this pressure needs to be set with a special instrument which the HVAC installer or HVAC start-up technician should have.
The manifold pressure should be set according to the furnace manufacturer’s instructions. This is done by an adjustment on the regulator and valve as noted in the valve section (see gas furnace components). The setting will depend on the type of fuel, natural gas or LP, and the manufacturer’s instructions.
Gas Manifolds for Furnaces
The main burners are connected to the gas manifold usually by little brass fitting generally referred to as spuds. These spuds have precisely drilled holes in them. The size of these holes will depend on the type of fuel, propane or natural gas, and the amount of gas the engineer wanted to send into the burners. The precise amount of gas needed for the right size flame for the exchanger. Most furnaces come equipped with spuds for natural gas but liquid propane spuds are available. It is very important that the gas manifold pressure is set according to the gas furnace manufacturer’s instructions. Otherwise, an improper flame may be present in the combustion chamber.
Gas Manifolds Furnace Maintenance
Little maintenance is required of the manifold. However, if the unit is exposed to the elements as some gas packs are it is possible for tiny insects to get into the panel. Consequently, these insects can impede the gas flow from the spuds, and the furnace may not operate or may not operate properly. If an insect problem exists contact an exterminator. Never modify the furnace cabinet or block any vents which allow ventilation for the gas furnace. Consequently, this could result in improper and dangerous combustion inside the furnace heat exchanger.
High Performance HVAC Furnace Information
Gas Manifolds | Furnace Components