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Two pound – Placed at the residence and decreases the pressure from first-stage regulator to 2 pounds. Used in newer systems where the gas vapor demand requires additional regulation before the appliance.

WattsVacuum Relief Valve

Never attempt to modify, manipulate or repair regulators unless you are qualified to do so and have approval from the manufacturer.

NOTE: The opinions and viewpoints expressed herein are solely the author’s and should in no way be interpreted as those of LP Gas magazine or any of its staff members.

I typically write about personal safety, but in this article, I take a different approach and talk about a key element of safety within a typical residential propane system, the propane regulator.

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Because the regulator is the heart of the propane system and is the key element in ensuring safety, it is important to understand how it works. The Certified Employee Training Program and the consumer education materials provided by the Propane Education & Research Council are excellent sources of information.

Second stage (low pressure) – Typically placed at the residence and decreases the pressure from the first-stage regulator to inches of water column (often 11).

There are many different types of regulators designed to fit different applications. Sizing a regulator correctly for the load on the system is very important. Types of regulators used in residential applications include:

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Line (appliance) – Placed before the appliance and decreases the pressure from 2 pounds to inches of water column (often 11). Does not have integral relief and usually uses a vent limiter.

Integral two-stage (twin) – Some smaller load systems can bring container pressure down to inches of water column with a regulator that has both stages built in, sometimes referred to as a twin-stage or piggyback regulator.

While features vary among manufacturers, the basic components are the same in most regulators. The main parts of a regulator include:

Vacuum relief valveworking principle

The purpose of the regulator is to control the flow of gas vapor from the container to the burner tip. The regulator ensures safety by providing over-pressure protection, usually by means of a pressure relief device. This is why we often refer to the regulator as the heart of the propane system.

Inlet and outlet ports – The inlet is where gas vapor enters the regulator and the outlet is where it exits the regulator.

Automatic changeover – Similar to an integral two-stage regulator in regard to pressure regulation but also has a mechanism that allows it to monitor vapor pressure switching from one tank to another in a multi-tank installation. Read more: Understand automatic changeover regulators

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Vent – Built into the cover, allowing the regulator to breathe during normal operation. Vents can also be placed where the relief mechanism discharges.

Relief – If excess pressure flow beyond the capacity of the regulator occurs, the relief mechanism (spring) allows the propane vapor to exit through the relief valve. This prevents excess pressure from building.