Gas Pressure Basics

Gas Pressure is very critical to the installation and operation of HPC Fire Inspired fire features. If the pressure being supplied to our appliances is not correct the units will not operate correctly. If the pressure in the gas line is too high, it can cause damage to the unit, and if the pressure is too low it can cause small flames and nuisance drops outs. Today we will talk about gas pressure basics.

The pressure of a gas is the force that the gas exerts on the walls of its container, such as a gas line. We measure the gas line pressure with a monometer, which will read pressure as inches of water column (inch WC) or can be measured in millibars (MB). Most Residential gas deliveries will deliver gas to the meter at high pressure. The meter will then reduce pressure to 1/2 lb pressure to supply all appliances in the building. Propane systems are much the same in that the gas leaving the tank is at very high pressure, the regulator at the tank will reduce pressure to around 2lb or 56” WC which is still too high for normal appliances. In this scenario, there will another regulator in front of the appliance to reduce pressure once again to 1/2 lb of 14” WC. One pound of gas pressure will measure 28” WC. While the Propane system operates at a true 1/2 lb or 14” WC, natural gas on the other hand actually operates at ¼” lb or 7” WC, but is still referred to as 1/2 lb.

HPC Fire Inspired appliances are built to be operated at ½” pressure with a maximum delivery to the fire feature being 7” WC for natural gas and 14” WC for a propane system. The pressure is too high on either system it can damage the gas valve, make the valve hum or chatter, cause very tall flames, and make noise much like a jet engine. On the other hand, too low a pressure will cause very small flames, shrink pilot flames, which cause dropouts. If the natural gas pressure or propane is too high a regulator must be installed before the fire feature for proper operation of the unit. These regulators can be used with natural gas or propane and most of them are adjustable, meaning once installed the pressure within the line can be adjusted up and down on the outlet of the regulator. Below is HPC Fire Inspired operating pressure specifications

Natural Gas Nominal Operating Pressure:

  • 3.5” WC (minimum) to 7” WC (maximum) 6” WC recommended for optimal operation

Propane Gas Nominal Operating Pressure:

  • 11” WC (minimum) to 14” WC (maximum) 11” WC recommended for optimal operation

Hopefully, this helps with understanding how important gas pressure is to the installation, operation, and safety of HPC Fire Inspired appliances. Remember gas line pressure measurement is a crucial part of a proper install for any gas burning appliance and should be checked before any appliance is connected to any gas line. If you have any questions about this topic, please feel free to give us a call.