Gas Pressure and the Installation & Operation of Natural Gas/Propane Fireplaces
Establishing correct gas pressure is critical to the successful installation and safe operation of a residential fireplace. Incorrect pressure can lead to poor performance at best, and damage to the unit in a worst case scenario.
Gas pressure is measured as the force the gas exerts on the walls of its container. In this case, the container is the gas line to the fireplace. Measure line pressure with a manometer, which reads pressure as inches of water column (inch WC) or in millibars (MB). One pound of gas pressure measures as 28″ WC pressure.
The Consequences of Incorrect Gas Pressure
If gas pressure to the fireplace is too low, it can cause a weak pilot flame, very small burner flames, and annoying drop outs. If the pressure is too high, it can damage the gas valve.
Therefore, robust flames, quiet operation, and longevity of fireplace components is reliant on establishing correct gas pressure.
Nominal Operating Pressure for Residential Fireplaces
Nominal operating pressure for a gas fireplace depends on the type of fuel being used. While a Propane system operates at a true ½ lb or 14″ WC, natural gas operates at ¼ lb or 7″ WC but is still referred to as ½ lb.
Residential gas is delivered to the meter at high pressure, then reduced to ½ lb pressure to supply appliances in the building.
Operating Gas Pressure: 7″ WC (minimum) to 5.5″ WC (maximum)
Manifold Pressure: 3.5″ WC
The gas leaving the tank in a propane system is usually very high pressure. The regulator at the tank will reduce pressure to around 2lb or 56″ WC, which is still too high for a fireplace. Therefore, it will require the installation of an adjustable ½ lb regulator.
Operating Gas Pressure: 11″ WC (minimum) to 14″ WC (maximum)
Manifold Pressure: 10″ WC
More Information on Fireplace Gas Pressure
For more information about testing fireplace gas pressure with a manometer, check out Tech Tip: Fireplace Manometer Testing.
Does your fireplace require service? A Montigo authorized dealer in your area can help.