Definitions

Here are some common definitions that you may find useful when sizing a regulator.

Non-Lockup Type:

Under static conditions when no gas is flowing, outlet pressure will rise to line pressure. In other words, if you are using an electronic ignition system and the gas flow stops (after the call for heat is over) these types of regulators will allow the gas to keep flowing down stream until the pressure is equalized.

Lock Up Type:

Under static conditions of no gas flow, outlet pressure will rise somewhat above adjusted pressure but should not rise to line pressure.

Dead End Lock Up:

Pressure will be maintained slightly above adjusted pressure under static conditions when no gas is flowing and will protect the downstream controls, if properly sized.

Zero Governors:

Equipped with a counter spring beneath the valve. They require an external impulse signal, such as top loading with pressure or generating vacuum in the downstream piping. These are only for very specialized applications.

Differential Pressure:

This is simply the difference between inlet pressure to the regulator and outlet pressure from the regulator. To obtain differential pressure, just subtract the desired outlet pressure from available inlet pressure.

Pressure Drop:

The natural loss of pressure that occurs in the regulator (or in any valve or pipe) due to friction. This friction impedes fluid motion, without regard to artificial losses deliberately created by diaphragm action.