How to Adjust a Gas Regulator with Step-by-Step Instructions

Published onApril 9, 2024
How-to Guides, Resources

Adjusting a gas regulator is a simple process that can be done with a single screwdriver. To do this, remove the cap on top of the regulator to access the adjustment screw. With your screwdriver, turn the adjustment screw clockwise for more pressure and counterclockwise for less. To understand what adjustments you’re making to the gas pressure, you’ll also need a measuring instrument like a digital manometer to ensure the safety of your appliances and home.

Gas regulators help maintain the amount of gas pressure in your piping system and the volume of gas entering your gas-burning appliances. However, there are times when these regulators may need to be adjusted to increase an appliance’s efficiency or just to keep the appliance running.

This guide will teach you how to adjust a gas regulator the correct way, so gas is delivered safely and efficiently throughout your home to your appliances.

Table of Contents

When to Adjust a Gas Regulator

It’s never a good idea to start adjusting the outlet pressure of a regulator unless you know for sure it’s the reason causing issues with your appliances. Here are the most common reasons why a regulator might need to be adjusted:

Component Wear

Diaphragms inside the regulator can wear or become damaged over time, leading to a drop or surge in gas pressure. If your regulator is between 5 and 10 years old and you’re experiencing these changes in pressure, you should replace it instead of trying to adjust the pressure.

Appliance Issues

If your appliances are shutting off or not performing as expected—such as producing an uneven flame that’s either too high or too low—it’s likely because you have a pressure issue.

What happens if the gas pressure is too low?

Signs of low gas pressure include yellow or orange flames (indicative of incomplete combustion, which can lead to carbon monoxide poisoning), accumulation of soot around the appliance, and a noticeable decrease in the efficiency of the appliance.

What happens if the gas pressure is too high?

Common signs that the gas pressure is too high going to your appliance include loud noises from the burner or pilot light, excessively high flames in the burner, and appliances turning off unexpectedly.

When Converting From One Gas Type to Another

Besides services regulators, most appliance and gas line regulators are interchangeable regardless of which type of gas is being used.

For example, if you want to convert your propane grill to natural gas and there’s already a regulator in place, you can just adjust it instead of replacing it.

Or maybe your local propane prices are high, and you want to convert your propane furnace to natural gas to save money.

You can do that too. And you don’t have to spend any money on a new regulator.

As long as you adjust the regulator pressure to match the gas type you’re using, you shouldn’t have any problems using the same one.

After Installing a New Appliance

When you add a new gas appliance to your home, the increased demand on your gas supply can change how much pressure is distributed to your other appliances.

Checking the outlet pressure of your regulators with all appliances running will confirm each one is receiving enough pressure to function correctly.

Don't just assume your pressure issues are because of a regulator. In some cases, your pipe size might not be large enough to provide the volume of gas required.

You should also be pipe-sizing your home anytime you add new appliances. If you need help with this, you can use our gas pipe sizing calculator.

Gas Pipe Sizing Calculator

If you need to increase or decrease your regulator pressure because of one of the reasons mentioned above, follow the steps outlined below on how to adjust a gas regulator.

A Step-by-Step Guide on How to Adjust a Gas Regulator

Below is our step-by-step guide on how to adjust a gas regulator.

We’ll cover what tools are needed, how to set up a test connection port, as well as specific considerations for adjusting pressure regulation in gas valves.

Here’s how to do it:

Tools and Material Needed

Flathead Screwdriver: To remove the regulator cap and adjust the internal spring.
Manometer: To understand what pressure adjustments you’re making and to set the regulator’s outlet pressure correctly
Barbed Tube Adaptor Fitting: To be used as a test port for the manometer to read the pressure.
A ¾” to ¼” Reducer Bushing Brass Fitting: The reducer needed to connect the barbed tube adaptor to a gas nipple.
One ½” or ¾” Gas Nipple: To install the test port to your existing piping system.
Teflon Tape: To help seal the threads on brass fittings.
Two Adjustable Wrenches: Used to tighten the brass fittings to avoid shavings.
Channel Locks: To secure your gas piping when connecting and removing your test port assembly.
Pipe Dope: This is used to further seal the brass fittings and reconnect your gas piping once you’ve made your adjustments to the regulator.

Step 1: Create Your Own Test Port

Since most regulators don’t have an actual test port on them, you’ll have to create one yourself. You can make this with a reducer bushing, a couple of pipe fittings, and a barbed adaptor fitting.

First, check to see what the pipe size is after the regulator you want to adjust. You’ll want to measure the inside diameter (ID) of the pipe.

Once you know the diameter, you can buy a short, 4 to 6 inch gas nipple the same size and a brass reducer bushing that will connect to a ¼” barbed tube adaptor.

Take a look at the example shown below, you’ll see a ¾” gas nipple connected to a tee fitting with a brass bushing that reduces the size from ¾” to ¼” for the tube adaptor.

Find a Tee or other fitting with a plug in it to install your test port assembly.

Once you have your fittings together, apply a layer of pipe dope to the threads on one side of your gas nipple and connect your brass reducer bushing.

Use a channel lock to secure the nipple and an adjustable wrench to tighten the brass fitting.

Now, you’ll need to attach your ¼” barbed tube adaptor.

Anytime you connect brass to brass, it’s a good idea to wrap the threads in Teflon tape. This helps create a tighter seal.

Wrap the Teflon tape around the threads on your adaptor and apply a thin layer of pipe dope.

Using two adjustable wrenches, tighten the tube adaptor to the bushing, making sure you don’t overtighten it.

You now have a test port you can connect anywhere in your piping system to test the pressure.

Note: You can also create the test port on an existing gas nipple, but having a dedicated assembly allows you to test the gas pressure at different points throughout your piping system.

Step 2: Turn Off Your Gas Supply To The Regulator

Before connecting the test port to your existing gas piping system, make sure to shut off the gas supply to the regulator.

If you don’t see a gas ball valve installed before your regulator, trace the gas piping further back until you see one on the same gas line as the regulator you want to adjust.

If you don’t have a shut-off valve anywhere, you can turn the main gas supply off where it enters your home. Just keep in mind this isn’t the ideal solution.

This gas shut-off valve is in the off position. Notice how it’s lined up against the pipe, not with it.

In most U.S. states, a shut-off valve is required by code before every regulator and gas appliance. This is so the regulator can be replaced if needed or to clean out the drip leg, which is designed to change the direction of gas flow so dust or debris doesn’t enter the regulator.

It’s also used to isolate a gas line if there’s a leak or to turn off an appliance having issues instead of cutting all your other appliances off.

Step 3: Connect Your Test Port

Once the gas is turned off, you can install your test port. Look for a tee fitting with a drip leg or a another fitting with a plug in it after the regulator you want to adjust.

Unscrew the existing fitting and replace it with your test port assembly using two channel locks. Make sure to add a layer of pipe dope to the threads of your gas nipple before connecting it to your existing pipe.

If you can’t find a place to connect your test port, you’ll need to add a tee or 90-degree elbow fitting to your existing pipe.

Step 4: Connect Your Manometer to the Barbed Tube Adaptor

Before you cut the gas back on, connect your manometer to the tube adaptor.

I recommend using the Fieldpiece Dual-Port Manometer—SDMN5 because it measures gas pressures up to 60 inches of W.C.

Many other manometers max out at 5” W.C., which is fine for testing pressures on a gas valve. However, you’ll be looking for measurements between 7 and 12 inches of W.C., so you’ll need one that can measure more.

Check Price on Amazon

To do this, find the two ports on the top of your manometer. These ports are where the gas enters the manometer. Using the clear tube that came with your manometer, take one end and push it all the way down onto one of the ports.

Connect the other end of the same tube to your barbed tube adaptor that’s connected to your pipe system.

Step 5: Set Your Manometer to Measure for Inches W.C. and Zero it Out

Most manometers are capable of measuring in different units, including inches of water column (w.c.), which is the standard unit for gas pressure in residential applications.

Look for a “unit” button to press and cycle through the different measurements until you see “in. W.C.” or “inH2O” on the screen.

It should also have a “zero” button you can push and hold until it reads 0.00 on the digital screen. Don’t skip this step.

If you forget to zero out your manometer, you’ll get incorrect readings when adjusting your regulator.

Step 6: Turn the Gas Back On and Check Your Initial Readings

With everything connected, you can now turn the gas supply back on and fire up your appliance.

As the gas flows through the regulator, you’ll start to see the reading on your manometer increase.

Once it levels out, check to see if it’s providing the pressure you need. If not, it’s time to adjust your regulator.

Step 7: Remove the Cap Screw

To adjust a gas regulator, you’ll first need to remove the cap screw on top of the regulator. Some caps will have a slot for a flathead screwdriver to fit so you can turn it out. If it’s stripped, you can take a channel lock and unscrew it.

Using a flathead screwdriver, turn the regulator cap off to access the adjustment screw.

Step 8: Adjust the Regulator to the Correct Pressure Setting

Once the cap screw is removed, you’ll see the adjustment screw with another slot for a flathead or Phillips head screwdriver. This adjustment screw is what you’ll use to adjust the spring in your gas regulator.

The spring is what pushes against the diaphragm to maintain the set gas pressure leaving the regulator.

You can slowly tighten or loosen this adjustment screw to get your spring where it needs to be to set the gas pressure to what you need.

Once you remove the cap, you’ll see the adjustment screw to set the regulator outlet pressure.

To allow more gas to flow through a regulator and increase the pressure, turn the adjustment screw in a clockwise direction, tightening it. This will strengthen the spring on top of the diaphragm, which means a higher gas pressure is required before the diaphragm will seal the valve inside.

To drop the pressure, you’ll turn the adjustment screw counter-clockwise so it takes less pressure for the diaphragm to seal the valve once the pressure is met.

As you make these adjustments, keep an eye on your manometer. Make small adjustments and let the pressure settle before adjusting it again, as it can take a couple of seconds to level out and give you an accurate reading.

Once you have the pressure where you want it, you can turn off the appliance and gas supply.

Step 9: Remove the Test Port and Turn the Gas Back On to the Appliance

Once you have your regulator pressure set, replace your test port assembly with the fitting you removed from your piping system. You can now turn the gas back on and purge out the air in your gas line.

Anytime you remove a gas fitting from a piping system, it will introduce air into the line. This means your appliance won’t light until all the air is purged out of your system.

If your gas appliances have an automatic ignition pilot system, you may need to cycle through the ignition process a few times before all the air is removed.

These pilot systems have a flame sensor that will lock up the gas valve if it doesn’t sense a constant and full flame after attempting to light the pilot 3-4 times.

For gas appliances without an automatic ignition, you’ll have to hold the pilot down and keep pushing the igniter until it lights. Usually, you’ll start smelling gas right before it ignites.

The Components of a Gas Regulator and How They Work

Before adjusting a regulator, you should understand its components and how they work together to regulate gas flow.

A Diagram of a 325 Series Maxitrol Gas Line Regulator. Photo Credit: Maxitrol

Diaphragm

The diaphragm is a flexible membrane that senses changes in pressure inside the regulator. It maintains and controls the opening and closing of the regulator valve based on the pressure sensed downstream.

Spring

The spring used in a regulator is located on top of the diaphragm. It provides a counterforce to the diaphragm to help maintain a constant, set pressure.

The tension of this spring is what you adjust to change the outlet pressure of the regulator.

Valve

The valve controls the flow of gas through the regulator. It’s connected to the diaphragm and opens or closes based on the diaphragm’s movement.

When the diaphragm senses a drop in pressure, it moves down, causing the valve to open and allow more gas to flow.

Once the downstream pressure is met, the valve is pulled up to restrict the flow of gas until another pressure drop is sensed.

Vent Limiter

A vent limiter is a safety component used on gas regulators to restrict the amount of gas that escapes through the regulator’s vent if the diaphragm fails.

It also allows the regulator to “breathe” during normal operation (to accommodate pressure changes) while keeping the amount of gas released at safe levels. They’re mostly used on regulators installed indoors.

These components work together to maintain a constant set pressure so you get an efficient flow of gas to your appliances.

The Different Types of Gas Regulators

Before you start adjusting any gas regulator, you need to know which type of regulator can be adjusted. Line regulators and appliance regulators are the two most common. However, there are other types of regulators you shouldn’t touch at all. Let’s go over these.

Service Regulators

Whether you use propane or natural gas in your home, you’ll have a regulator that reduces the high-pressure gas coming from the distribution point down to a safe residential level.

For propane, you might have one of two setups. This will depend on how precise you need your pressure to be going to your appliances. These two regulator systems are:

A Single-Stage Regulator System
A Two-Stage Regulator System

Single-Stage Regulator

A single-stage regulator system uses one regulator to reduce the high pressure in a propane tank to a usable residential pressure of 10 to 12 inches W.C. (water column).

These regulators are commonly used on smaller, above-ground 100 to 150 gallon propane tanks where there’s a short distance between the tank and the equipment being used.

Because there’s only one regulator breaking the high-pressure propane down, the output pressure can fluctuate. It’s best for simpler setups where these variations in pressure don’t affect the appliances.

Two-Stage Propane Regulator System

A two-stage regulator system is most commonly used on larger underground propane tanks, which hold 250 to 500 gallons and are buried away from a home.

This regulator system is called “two-stage” because it drops the high-pressure propane coming out of the tank twice before entering a home. This provides a more consistent and accurate pressure to appliances with less variation than a single-stage regulator

For larger underground tanks, the first regulator, or “first-stage” regulator, is a small non-adjustable regulator located on top of the propane tank. It’s job is to reduce the high-pressure propane down to 10 psi.

From there, the propane gas travels underground in gas piping until exposed again at the side of your home, where it will go through a “second-stage” regulator.

This second-stage regulator drops the propane from 10 psi to a residential level of 11 inches W.C. (water column) or 2 psi.

This two-stage system can also be used on smaller propane tanks through one single regulator assembly. These are typically called “twin-stage” or “dual-stage” regulators.

This regulator assembly breaks down the pressure on smaller propane tanks twice, with the high-pressure regulator and low-pressure regulator in line with each other.

A two-stage regulator system gives you more control over the outlet pressure since most second-stage regulators are adjustable, while one-stage regulators aren’t. This is helpful when using appliances like water heaters and heating systems that are susceptible to under or over-firing.

Natural Gas Meter Regulator

Natural gas is supplied to residential homes through a set of underground distribution lines. From the main gas line at the street, an underground service line is installed up to a home with a gas pressure of 60 psi.

Once this service line comes out of the ground, a service regulator drops the pressure to one of two residential pressures before entering the gas meter. These pressures are 0.25 psi / 7” W.C. (water column) or 2 psi.

The pressure used for your home will depend on the number of gas appliances being used, their total BTU load, and how far they are away from the gas meter.

Larger homes with multiple appliances will usually have a 2 psi meter regulator because there needs to be enough pressure to handle the entire BTU load of appliances running simultaneously.

Lower pressure regulators are typically used when there’s only one larger appliance, like a heating system or hot water heater, or two small appliances, like a gas range and gas logs being used.

A natural gas meter regulator breaks down the distribution pressure before entering the residential meter.

DO NOT make any pressure adjustments to your meter regulator. Doing so can cause your appliances to shut down or, in extreme cases, cause an explosion. Plus, you’ll more than likely receive a tampering charge from your gas utility company.

If you think the gas pressure in your home is too low, call your gas utility company and ask them to check the outlet pressure on this regulator.

They’re the only ones qualified to do this, and they’ll have the tools needed to make any necessary adjustments. They’ll also make sure your pressure is within safe limits.

If you have a low-pressure meter and you need more, most gas companies won’t charge you to upgrade your meter to a higher 2 psi pressure.

Gas Line Regulators and Appliance Regulators

Line regulators are used to reduce the pressure in a gas line before it enters an appliance.

If your home uses a 2 psi system, one of these regulators will need to be installed in line with your gas piping before each appliance.

This is because each gas appliance has a maximum inlet pressure requirement in order for it to operate correctly and safely.

The maximum inlet pressure for an appliance will depend on what type of gas you’re using. The typical range of supply pressures required for most natural gas and propane appliances like water heaters, gas ranges, and furnaces are as follows:

Natural gas appliances: 7 to 11 inches of W.C.
Propane appliances: 10 to 12 inches of W.C.

Any pressure going into an appliance higher than what’s shown above or specified by the manufacturer can lead to an uncontrolled flame that’s larger than it should be.

This can damage your appliance and create serious safety hazards. Higher pressures can also create gas leaks on any appliance connectors being used, as they’re only rated for ½ psi.

Pressure Regulators and Gas Valves

Most natural gas appliances operate at even lower pressures (3.5” to 4” W.C.), requiring the incoming gas pressure to be further reduced by an additional pressure regulator or from the gas valve itself.

Pressure regulators, typically seen on the back of gas ranges, control the gas pressure for the oven. If the output pressure is wrong on these, they’ll have to be replaced, as these can’t be adjusted.

The gas valve on propane and natural gas appliances will have a test port on the outlet side of the valve so you can see what pressure is going to the burners and adjust as needed.

Frequently Asked Questions for Gas Regulators

How to Reset a Gas Regulator?

To reset a gas regulator, start by removing the cap screw located at the top of the regulator. Once the cap screw is removed, you will be able to see the adjustment screw inside.

You can adjust this screw using either a Phillips or flathead screwdriver. The adjustment screw works in conjunction with a spring that sits on top of a diaphragm within the regulator.

If you want to reset the regulator to its lowest pressure setting, you can turn the adjustment screw counter-clockwise until it reaches the top. Once you have fully turned out the adjustment screw, you can begin to increase the gas pressure by slowly turning the screw in a clockwise direction.

Make sure you have a manometer hooked up to your piping system or the inlet side of your gas valve so you can monitor the pressure increase as you make your adjustment.

What Position Should a Gas Regulator Be?

A gas regulator should be installed in a position that aligns with the manufacturer’s guidelines, which is typically in a horizontal upright position for most residential line regulators.

For service regulators outdoors, the vent side should be facing downward to prevent moisture or debris from getting into it.

Can a Gas Regulator Get Clogged?

Yes, a gas regulator can get clogged with debris, dust, or rust particles over time, especially if a gas piping system lacks any drip legs or if the regulator is exposed to the elements without proper protection.

Signs that your regulator is getting clogged include fluctuating pressure levels or a complete blockage of gas flow.

What Happens If You Over-Pressurize a Gas Regulator?

Over-pressurizing a gas regulator can lead to dangerous situations, including gas leaks, appliance malfunctions, or even explosions.

Appliances and systems are designed to operate within specific pressure ranges—4 to 7 inches of W.C. for Natural gas and 10 to 12 inches of W.C. for Propane.

Exceeding the maximum inlet pressure on a gas appliance can cause it to shut down as a safety measure or completely fail.

Is It Normal for a Gas Regulator to Vent?

Yes, it’s normal and necessary for some gas regulators to vent small amounts of gas as part of their standard operation, especially regulators with vent limiters or over-pressure protection devices.

The venting helps regulate pressure and ensure safety. However, if you notice continuous venting or weird sounds coming from your regulator, call your local gas company to come out and inspect it.

What is a Manometer?

A manometer is a digital instrument used to provide accurate pressure readings for propane and natural gas.

These are typically used to get pressure readings on gas entering and leaving a gas valve. However, they’re also used to test the outlet gas pressure on regulators or the overall pressure in a gas piping system through test ports.

Final Thoughts

Knowing how to adjust a gas regulator comes in handy anytime you have pressure issues with your appliances or when adding a new gas appliance to your system.

Understanding which regulators you can adjust is also critical, as you don’t want to adjust any high-pressure regulators. This would include the “first-stage” propane regulators and natural gas meter regulators.

When adjusting regulators, you should always prioritize safety. Don’t blindly adjust a regulator. This can over-pressurize your appliances or lower the pressure so much that it begins to produce carbon monoxide.

Use the right tools and a measuring instrument like a manometer for accurate readings, and follow each step listed above carefully.

If you don’t have much experience with gas, it’s best to call a licensed professional in for help.

Any HVAC, plumbing, or gas technician should have the knowledge and tools required to determine the gas pressure your regulator is providing.