When we have free time we will often answer service and support questions on various question and answer web sites where people turn for help with barbecue grill and fireplace problems. Sometimes the same question will come up again and again so we’ll share it here. The funny thing is that these sites have
“experts” whose answers seriously call into question the designation of expert.
Do you need to use a natural gas regulator on your NG barbecue grill or fireplace?
The answer is both yes and no. Natural gas is typically provided to us through our city, state or county and is often contracted out to independent companies just like electricity. The standards for typical regulation is that natural gas will run through the main gas line at 110 psi which means 10 pounds of pressure per square inch.
When the gas line splits off the main to run up into someones property there is a regulator after the meter that steps the pressure down to 2 psi. At sea level a low pressure appliance like a barbecue grill and a gas fireplace will burn at low pressure which is between 1/8 and 1/4 of 1 psi. Because the pressure is so low we designate the pressure in terms of water column displacement. Low pressure appliances typically operate at 2″ or 4″ water column displacement and can operate higher at higher altitudes.
As the 2 psi gas line runs through your house it splits off to go to various appliances and each split should have a regulator to step the pressure down to where that appliance needs it. If the gas line running the the barbecue grill has a regulator stepping the pressure down to 4″ then it is not necessary to also have a 4″ regulator on the barbecue.
However, if the gas line is not regulated the pressure will be too high and the flames emitting from the burner will be pressurized to burn much more gas than we intend. For this reason we will usually advise homeowners to add a NG regulator to the barbecue even if it is not required. Gas lines can have peak periods and surges that can alter pressure but an extra regulator will regulate the variances of the gas line so the barbecue is always receiving the even flowing pressure it needs to operate properly.
A regulator is a simple chamber with an enter-door and an exit-door. The chamber in between the entrance and the exit is made of cast aluminum except on one wall of the chamber. This one wall of the chamber will be a rubber diaphragm and on the other side of the diaphragm is a coiled spring and the nut we see on the outside of our regulator. Removing the nut will give us access to the spring inside the regulator.
The pressure exerted by the spring compressed under the nut on one side and pushing on the rubber diaphragm on the other side will only allow the chamber of the regulator to allow so much mass. Based on the mass of the gas type the spring is set to limit the size of the chamber which slows down the gas flow through the chamber. This is how a regulator works. I once had a gas technician with over 10 years experience tell a customer that if they added a regulator when they did not need a regulator then their gas pressure would be too low to turn the barbecue grill on. If you understand how a regulator works you already know that is impossible.
A regulator does not automatically diminish the pressure that enters the chamber. The chamber will only allow so much gas through at any time. This means that if the pressure is running through the gas hose at 10″ the regulator will only allow 4″ to pass through the regulator. When the gas comes through the exit of the regulator it will be at 4″ of water column displacement because the regulator only allowed that much to pass through.
If we add another regulator to that same gas line what happens. The gas is now at 4″ as it enters the next regulator and this regulator spring-diaphragm will only allow 4″ to pass through it. What happens? The gas passes right through without being slowed down at all. We could easily attach 5, 10, 20, 100 regulators to a gas line and if they all have the tension of the spring set the same only the first regulator will slow the gas pressure down. The gas will then be at the lowered pressure which will pass through the series of regulators without any resistance at all.
This is important because now you know there is no danger and no diminished gas flow if we have an extra regulator on an gas line.
However, the reverse is very dangerous. If we need a regulator because the pressure is too high and we use a BBQ without a regulator we risk a major fire because our flames will be too high but also because the valves, gas hoses, adapters are not made for higher pressures and the gas may leak in many places if it comes into the appliance unregulated.
For that reason we will usually suggest that a customer with a natural gas barbecue install a natural gas regulator. Although there may be a regulator added by the gas company so the gas line pressure is already where it is needed by the grill if that regulator ever fails or the gas line gets a surge that damages the rubber diaphragm there is nothing to stop the flow of gas pressure. This can be a serious safety hazard.
Even if it is not necessarily required to have a NG regulator on a natural gas barbecue grill it is always a good idea to install an appliance regulator as a safety net.