Appliance gas pressure regulator questions & answers:

This article answers frequently-asked questions about gas pressure regulators commonly used on appliances, gas fired heaters, water heaters, and similar equipment.

This article series explains LP or Natural Gas Pressure Regulators used on building appliances such as gas fired furnaces, boilers, water heaters, and stoves: How to Inspect & Test LP or Natural Gas Valves Regulators, or Gas Controls at Appliances.

Q&A on Gas Appliance or Heater Regulator or Controls

These questions about gas pressure regulators were posted originally

at GAS REGULATORS & APPLIANCE / HEATER CONTROLS. Be sure to review the explanations and troubleshooting advice given there.

Photo at left: a gas pressure regulator for a gas cook top or range. Page top photo: gas control & pressure regulator for a gas fueled furnace.

Rinnai Gas Wall Furnace Damaged by Testing by Installer at 50 psi?

Recently a Rinnai gas wall furnace was installed in our home. The manual states the appliance must be isolated from the gas supply when testing the gas supply line.

The propane tank provider open the shut off valve at the unit and perform a 50 psi pressure test of the gas supply line.

Rinnai specifies that the line pressure should not exceed 1/2 psi.

Could his have caused any damaged to the unit? It seems to be operating correctly. I did call Rinnai Support, and they said it could have caused damaged; but did not give any specifics on possible damage. On 2016-11-03 by Dan

by (mod): Watch out: Rinnai advised you not to test above 1/2 psi

Dan,

Rinnai is of course the most authoritative source on their equipment, and I agree with their position in this matter.

Nobody is likely to take the chance of betting your safety and money on a promise about a gas fired heater based on a telephone call or e-text question. Search InspectApedia.com for OTHER PEOPLE's MONEY to understand what happens.

The risk is that a gas regulator or other gas carrying control or equipment is damaged and becomes unsafe. Fortunately the most-obvious damage, such as a ruptured diaphraghm in a gas regulator would show up quickly as a gas leak.

But there could be more subtle damage such as forcing a regulator or control out of calibration. Here's an example IO Manual from Rinnai that includes additional contact information for Rinnai HVAC.

Rinnai HYDRONIC AIR HANDLER MANUAL [PDF]

by Dan

Thanks. I understand most appliance gas control assembly (for heaters) incorporates a gas valve that is instructed to open to permit gas to flow into the appliance's burners when the thermostat calls for heat.

Are these control valves normally before or after the appliance internal regulators?

Moderator reply: individual heating equipment gas shutoff valve should be ouside the appliance itself

Because the gas regulator local to the appliance is usually inside the appliance, the appliance gas shutoff valve is and should be found ahead of and outside of the gas fueled appliance itself.

In an emergency in which we have to turn off gas to an individual appliance, we don't want someone to have to be removing appliance or heater covers and searching for the gas shutoff valve.

 

Can I remove a big old gas regulator that's in the way?

Can I get rid of 2nd pressure regulator? Connecting new oven/range.

Old big pressure regulator sticking out of floor, new oven/range has its own regulator built in, so is the old one (original 1980's, the range I'm replacing is not original).

If I leave it on, new oven has no cavity in back, won't be able to get oven flush to wall. On 2017-02-19 by MikeJ

Reply by (mod) -

I don't know, Mike as I don't know what regulators are installed where on your building.

If the old regulator is dropping high gas pressure down to appliance-range pressures then you need it.

DO NOT try just unscrewing a regulator to remove it as - obviously - you could get blown up.

And delivering too-high gas pressure to the regulator for the appliance can also cause a fire or explosion. Search InspectApedia

for GAS REGULATORS & APPLIANCE / HEATER CONTROLS to read details.

An expert would follow the whole gas piping system from source through the building to find what equipment is installed, what's needed, and to be sure the installation is safe.

Plumber omitted secondary gas pressure regulator so all my appliances are at too-high gas pressure?

My natural gas company supplies 2psi pressure to the house.

When replacing the flexible gas pipe in my house the plumber neglected to install the regulator dropping the house pressure to 1/4 psi. As a result the appliance regulators have been operating at 2 psi inlet pressure for two years.

Should I be concerned about damage to the appliance regulators? The problem has been corrected by the gas company changing their regulator. Furnace, water heater and cooktop seem to be operating okay. On 2016-08-30 by Russ

by (mod)

Russ:

Watch out: I'd give a call to the manufacturer of your specific appliance to ask that question. It's possible that some regualtors, particularly devices using a thin diaphragm to control pressure, could be damaged and unsafe.

Supporting research on gas regulator inspection

• AIHA: faulty gas regulator causes explosion: Investigation of Steel Plant Explosion Focuses on Gas Isolation Valve [Web article at AIHA] (2025)
  
  Excerpt: A fatal explosion at a Pennsylvania steel plant in August occurred during maintenance on a gas isolation valve, according to an update issued by the Chemical Safety and Hazard Investigation Board (CSB).
  
  The explosion killed two employees and caused extensive damage at the U.S. Steel Clairton Coke Works facility, which processes raw coal into coke, a component in the making of steel and iron. Five other workers at the facility were seriously injured.
  
  Here is the U.S. Chemical Safety and Hazard Investigation Board Report (2025)
  
  This document provides an update on the CSB’s investigation of the August 11, 2025, incident at the United States Steel Corporation (U.S. Steel) Clairton Coke Works facility in Clairton, Pennsylvania.
• Russ please see this InspecApedia.com article on inspecting gas regulators at the LP Gas Tank
  
  GAS REGULATORS for LP TANKS
  
  

After new gas regulator was installed our furnace pilot light is too big and won't stay lit

We recently had a new regulator put on the gas line from propane tank to house.

Now it seems that the pilot light of furnace,is burning to big and although it will stay litfor a while, it will always go out. Is the regulator allowing to much gas pressure? On 2016-05-09 by Don taylor

by (mod)

Don:

Watch out: If the regulator was not properly adjusted the pressure could be too high - which could be dangerous.

Or the thermocouple that verifies that a flame is present could be defective. Ask your gas regulator installer to return to double-check the system pressure and the pilot light.

Can I regulate too-high gas pressure by partly closing the gas valve?

Any issues with partially closing my lp shutoff valve near the furnace? It significantly reduces burner noise. On 2016-04-06 by Allen

by (mod) Watch out: no that is an improper and dangerous "fix"

Allen,

There is an implied issue: the gas pressure affects the gas flow rate if all other system features (pipe diameter, length, elbows, orifices, valves) remain the same.

So if partly closing a gas valve corrects a burner problem, you are treating the symptom but not the root problem. Quite possibly the gas pressure regulator for the gas delivery system is not properly adjusted.

That would be an unsafe condition, and your heater as well as other gas appliances may not work properly.

If a gas burner flame is inadequate a result can be production and release of fatal carbon monoxide gas.

So, if the furnace gas burner is not working properly, that is if the noise is not normal, your system needs service and / or repair. Part of that repair should involve checking and confirming that the gas regulators are adjusted properly for your home.

How to hook up a natural gas powered electrical generator

Hi I have a 6500 watt generator that I want to connect to a Natural gas line. I'm told I need a natural gas regulator but I am getting very confused re all the input I've received about which one will work. Below is the info re the generator. Can anyone tell me what regulator I need to buy....Please? May 1, 2015) melody rittenhouse

Engine: Powerland 16 HP tri fuel engine with a cast-iron cylinder sleeve.

Max Power: 16 HP/3600 rpm.

Engine type: OHV25 Tilt single cylinder forced air cooling 4 stroke.

Cast Iron Sleeve and Steel Bearings maximize engine life.

Special carburetor and secondary gas regulator allows the engine to operate on the most convenient fuel-gasoline, LP gas, or natural gas.

LPG inlet pressure: between 10-15 psi.
NG inlet pressure: mini. 0.25 PSI or 6" water column

LPG end fitting: 3/8" Flare/S.A.E
NG end fitting: 1/2" male NPT fitting with an optional 1/2 to 3/4" female NPT adapter

NG line size (recommended): 3/4"

Engine oil grade: 10W30

Start system: recoil/electric start (battery included).

Noise level: 70 dB @ 22 feet.

Reply:

Watch out: Melody this is not work that you should be doing, and depending where you live you may be required to obtain a building permit, inspections, and to have this work performed by a licensed professional. The risk is blowing up the house and killing everyone or poisoning the occupants with carbon monoxide.

The specifications you listed showed "NG inlet pressure: mini. 0.25 PSI or 6" water column " - that's the natural gas pressure presumably at the inlet to the generator.

 

Gas burner won't ignite

My natural gas furnace hotair pilot light and thermocouple stays on but when it calls for gas/heat, the unit wont fireup ? WHAT DO I DO ? (Dec 20, 2015) Anonymous said:

Reply:

If the pilot stays on but you don't find the main valve opening I suspect a problem at the gas valve. Your service tech may try replacing the valve.

Gas regulator turns from green to yellow

When regulator turns green then yellow what does that mean? (Dec 28, 2015) Beverly said:

Reply:

Beverly

I am GUESSING you refer to a warning light on a gas control - but I don't know: color codes are product and model dependent. It sounds like an unsafe condition for which you'd either find a relaxing answer in the installation and operation manual for your heater or appliance, or you'd shut it off immnediately and call for repair.

How do I make a gas regulator adjustment on a deserted Caribbean Island

We live on basically a deserted Caribbean Island and have to figure out how to do everything ourselves unfortunately. I have propane tanks with ~125psi and no regulators. I purchased a Fisher R622H which I installed at the tank and which reduces the pressure to "10psig / 0.69 bar." I was also going to install a Maxitrol 325-3L just inside the house where the propane lines come in.

This regulator states CSA rated inlet pressure 2 psi and the pressure range is 7-11" WC.

My gas stove stated it needed a minimum pressure 11" WC and maximum 13" WC to the inlet pressure to the regulator (on the Range). It also stated "you must use the gas pressure regulator supplied with this range." After hooking everything up the stove burners work fine, but the oven does not light.

I did not install the Maxitrol, which might be my mistake. My first question is will the Maxitrol work downstream of the Fisher valve and installing one of these just inside the house will control the house appliance pressures needed? My second question has to do with the range.

Do I go ahead and add the Maxitrol and see if the oven works? I am concerned we may have screwed up the Range regulator by not having this installed? (Jan 16, 2016) Mark said:

Reply:

Mark, if I've got this right, 10 psi is about 277 inches of water column, do yes you need both stages of pressure regulation.

Your Maxitrol wants just 2 psi inlet pressure.

Separately, unless your range uses 2 regulators, if burners work correctly and oven goes not, I suspect the lighting problem is a different issue. It may require more time foe an oven burner manifold to fill with gas.

You understand risks of fire and explosion, right?

At our oven I keep an igniter flame at the pilot or burner constantly while igniting it to minimize the risk of setting off an accumulated cloud if LP gas.

Is it ok if a gas regulator located in the attic is placed with vent face down?

Natural gas regulator in an attic in NC with a very small vent should still be facing down to allow condensation out- correct? (Mar 11, 2016) Brian said:
Thanks

Reply: no

Brian:

This is a trick question, right? What's a gas regulator doing in the attic?

Watch out: Typical gas regulator instructions require that the regulator be installed upright and horizontal - that will leave a vent facing down BUT venting INSIDE the building may be unsafe and illegal, risking a fire or explosion. Check with a licensed plumber or your building department.

 

Is 1/2-inch plastic gas pipe adequate for my garage heater?

2016/03/13 Mrots said:
Hello, I have a 45000 btu ,l.p. Garage heater . It is running on 200 feet of 1/2 inch plastic gas line, then to a regulator , and 1/2 inch pipe from there.

My question , is the piping sufficient for capacity ? Do I need a bigger regulator ? The heater keeps going out , then relighting.

Reply:

Mrots

Plastic gas piping has been in use since about 1997; Fire Engineering (and others) have recently published articles discussing the use of plastic gas piping and its safety; you might want to research and read some of that;

Havel, Greg, "Construction Concerns: Plastic Gas Pipes", Fire Engineering, 12/092007 (available as a PDF] www.fireengineering.com/articles/2007/12/construction-concerns-plastic-gas-pipes.html

I'm doubtful about your gas piping diameter and adequacy and suggest consulting with your local gas supplier or a plumber experienced and expert in gas piping. Your system might simply need to be run at a higher stage 1 regulator pressure. Sorry I can't give specfic design suggestions for your heater as it's beyond what's safe from a mere e-text.

Certainly if the flame is going out the system may be unsafe, risking fatal carbon monoxide production. Be SURE that you have properly-installed, working CO detectors.

Gas regulator capacity, sizing, adjustment, can be found in more detail at GAS REGULATOR ADJUSTMENT PROCEDURE and in manufacturer's documents linked-to in that article. CHeck with the manufacturer of your regulator.

Should a regular home inspection be able to detect a faulty gas pressure regulator?

Should a regular home inspection be able to detect a faulty regulator?

Is a faulty regulator something that is easily detectable to the trained/thorough eye? On 2012-10-25 by Kate

by (mod) - maybe

Kate,

Forgive us but.... no, well yes, maybe in some cases. Not by mere visual inspection, but by operating the gas fired equipment - if it's a building heating boiler or furnace for example, the inspector may observe an abnormal flame, noise or other clue of a bad regulator.

Most home inspectors won't try to operate all gas appliances and their controls such as gas ovens or cooktops.

But unless special circumstances prevent, the inspector is expected to operate normal homeowner controls to run the heater.

If that was done, and IF there was visual access to watch and see the gas flame at and during ignition, and IF the particular defect was present at that time, and if the particular defect is one producing a visible or audible abnormal operation then ... yes s/he should have reported it.

In sum, maybe.... it depends

The gas regulator pressure isn't changing when I turn the adjusting screw - is it defective?

The gas pressure at the burner manifold on my 20-year old boiler reads 3" WC.

I've tried to adjust it (at the gas valve) to achieve the 3.5" WC requirement, according to boiler spec. I'm unable to get any response (plus or minus) when I turn the pressure adjusting screw.

Shall I assume I have a faulty gas valve? What negative issues are there if I continue to operate the appliance in this condition? Thanks to all for the valuable information found on this web site. On 2011-11-21 by Joe R.

by (mod) -

Is this LP or natural gas Joe? If LP and your location is in very cold weather you may be seeing lower pressure and flow rate from the tank, or a partly iced gas regulator outdoors. I'd ask your gas company to come out and make their own measurements to compare with yours, and to check the regulator.

I'm not sure just how dangerous is a .5" under-pressure condition, and will do some further research.

Or you can give me the name of the boiler manufacturer and the model and serial number (and tell me if it's LP or NG) and we can ask the manufacturer about the allowable pressure variation and about what safety concerns may arise such as an inadequately heated flue, improper combustion (that can be dangerous) etc.

by Joe R. - utility company says the natural gas pressure is correct for this Burnham boiler

Thanks Dan, The boiler is fueled by natural gas. I did have the utility co. come out and test their delivered pressure.

He witnessed my manifold gage reading while the boiler was firing. He assured me the line pressure upstream of the gas valve was quite adequate. This is a Burnham boiler, model no. P206AWNV, serial no. 17234540.

I am also uncertain of the maximum or recommended high temperature limit switch setting. It is not stamped on the boiler data plate nor is it mentioned in the operating manual.

I contacted Burnham recently concerning this, but couldn't get past the switchboard operator. She claimed they had no information about this boiler because of its age. I'm not sure I buy that.

Joe, in GENERAL, the high limit on a boiler will be set to 200 F or less. Setting to temperatures above that level risk dumping the pressure/temperature relief valve.

...

Continue reading  at GAS REGULATORS & APPLIANCE / HEATER CONTROLS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see GAS REGULATORS for APPLIANCES FAQs-2 - more-recent questions & answers about appliance or heater gas regulators posted originally on this page.

Or see these

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• GAS REGULATOR ADJUSTMENT PROCEDURE
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• GAS REGULATORS for LP TANKS
• GAS REGULATOR NOISES
• GAS REGULATOR TEST PROCEDURES
• GAS REGULATORS, TWO STAGE

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