Natural Gas Pressure?

[Glenn9643]

I realize that this is not tractor-related, but I feel that I might get a better answer(s) here... Surely you understand.
We use natural gas for heat, water heat, and cooking. I've noticed a problem when lighting the burners on top of the stove at times during the last eighteen months or so. This is very intermittent. Our stove has electric ignitors and you turn the burner to high to start the gas and back to "ignite" to get a flame. Usually you turn the knob and the burner lights as it should. BUT, there are times when you can't get it to light. When this happens it sounds as if the gas it over-pressured, and the only way to light it is to turn the burner down to the lowest setting and use a match. Even then the flame won't go all the way around the burner. If you turn it up it seems to blow out. After a few minutes of burning like this it gets back to normal. I'm aware that the stove has a pressure regulator on it that should control the gas flow, but I'm not sure if this is a problem with too much pressure in the line from the company or not. It seems as if there's too much pressure, but it also seems like what's coming out isn't gas because you can't get it to start. Is there anyone here that can give me any ideas? I'm going to call the local gas company next week about it, but I don't want to be scammed. Thanks.

 

[PineRidge]

Glenn9643 I would imagine if you had a problem with the main regulator at your gas meter a problem such as this might arise. I have even seen some regulators freeze in the winter causing this type of problem. Most appliances such as hot water heater, furnace, gas dryer, and the like all have additional pressure regulators that further drop the gas pressure to around 3.5 inches of water column. I don't know of an easy way for you to check the pressure but your public utility will most likely use a manometer to verify gas pressure readings. Sorry I can't lend you mine or I would. /forums/images/graemlins/grin.gif

 

[Bird]

Glenn, I can't say for sure just what the problem is, but I do know that gas companies use a lot of different pressures in their gas mains. Some actually use a low enough pressure in the gas main that no regulator is necessary at the meter, some have a single regulator at the meter, and some even run high enough pressure that there are two regulators (two stage regulator) at the meter. And while it isn't very common, a regulator can certainly be or become defective. So you definitely do need to contact your gas company. However, your comment </font><font color="blue" class="small">( After a few minutes of burning like this it gets back to normal )</font> makes me wonder if the problem might be with your stove instead of the gas company's pressure. And I just don't know.

 

[Glenn9643]

Bird,
It seems to me that if there was a problem with the stove it would be consistant. This has been about four or five times in the past year. Doesn't last more than about a day. When the stove won't light as it should it seems almost like the gas isn't gas, but just air because when I turn the burner to the lowest setting and light it the burn is only about a third around, and when I turn it up it will "blow out". I was hopeful that someone might have experience or be knowledgeable about natural gas and help in this area. Basically, I didn't want to be told by the gas people that it was my problem without a little more knowledge and thought perhaps someone here might help.

 

[carrickfad]

Glen, are all the burners acting this way? On my stove top (Jenn-Air) the one burner we use more then the others has to be adjusted usually twice a year, spring and fall. I don't know if it's because of the change of weather or what. To adjust it I light the burner then take off the knob. Down inside of the stem there is an adjustment screw I give it a little twist with a screwdriver and the flame goes from Med to Low like it should be. I found my solution through an online manual at the Jenn-Air web site. Maybe you can find your stoves manufacturer online and find a solution.
Good Luck,
Mike

 

[thcri]

A lot can depend on if you have a 2psi system or not. Most stoves will have a regulator on them to drop down to the 3.5". I have seen many regulators that will get dirt in the seal and will not totally shut down when all appliances are off, thus allowing the full 2psi to go to the appliance. A lot of gas valves will not open at that pressure but some will. Stoves will because you manually open them. We had a regulator one time leak through during the off cycles and with time you would have 2psi on both sides of the regulator. The peoples furnace, water heater would not start at this point. It took over an hour for the regulator to start leaking through which made it tough to diagnose.

Another thing that could be going wrong is you could have air in the line. This can come from maintenance being done on the main lines. One thing I know our local supplier will do is inject LP gas in the lines during the real cold months to help keep the pressure up.

The stove at our cabin will do that at times also. It is not electric ignition but does have pilot lights and we typically light the stove with a match most of the time and we will have to keep the valve way low to prevent the flame from jumping off the burner. The stove at the cabin is LP Gas

Gee I think I said too much!!!

murph

 

[carrickfad]

One more thing Glen. Sometimes on my stove (it's also natural gas) the holes were the gas comes out get clogged when we just wipe it down with a sponge. I guess it forces grease or whatever back into the holes. So the stove looks clean but really it's dirty inside so when I light it a bigger flame shoots out one side, same volume of gas through fewer holes equal greater pressure (I think) and then when the whole assembly heats and the grease or whatever burns off the flame goes back to normal. When this happens I soak the stove parts in hot soapy water and clean the holes with a toothpick. Hope you find the solution.

 

[Egon]

Really curious about the injection of C3 into the line to raise pressure as it has a lower vapour pressure than methane. It will add Btu content to the fuel.

Maintenance procedures are such that air should not be introduced into the lines. In fact great care is taken to purge any air out of lines that have been worked on.

Egon

 

[Bird]

Glenn, I can't say I'm particularly knowledgeable about natural gas, but I did spend a couple of years doing gas leakage surveys for gas companies. And I think all the comments made so far in this thread are good; dirty burners (even though they look clean), the adjustment screw, regulator freezing, etc. The only time I had a real problem personally was during one of our infrequent, freak ice storms and the gas pressure fell so low the furnace would not ignite and I could barely get a tiny flame, even wide open, on the cookstove. When I called the gas company, they said they would send a man to check it, and in the meantime, that I might try pouring hot water on the regulator at the meter because sometimes moisture can cause them to freeze up. As it turned out, it wasn't the regulator at our meter; it was low pressure throughout a large area and was corrected by the gas company within a couple of hours.

And Egon, Murph is right about injecting LPG into natural gas lines. I don't know how many places do that; I only encountered one when I was doing the gas leakage surveys. That was a gas company that had about a 15 mile main bringing gas into the town and it was too small a line to allow an adequate volume in extreme conditions because so many people had converted from fuel oil to natural gas that the system was simply inadequate even though it had been sufficient at the time it was installed many years earlier. And while I don't remember many details, there has to be special equipment for injecting the LPG and there's a maximum ratio or percentage of LPG that cannot be exceeded.

 

[Egon]

Bird:

Got it Bird. The C3 has many more BTU's than methane so injecting it will raise the effective capacity of the distribution system. Limits have to be because the methane jet orfice is larger than the C3 orfice and too much propane could result in some problems with overheating.

This was a situation never encountered in my small world.

Although one time I did manage to shut down an entires town's gas supply due to technical control problems and a urgently required bathroom break.

Egon