Gas pressure

[koditten]

Does city gas pressure ever vary? I like to look at my flame every week or so and I swear that the flame will look different from time to time. Maybe I'm a bit ****, but I need to know that the regulator is keeping the proper gas supply to my boiler. Should I have the gas pressure checked periodically? Is using a manometer a difficult skill? What are the risks.

FYI, I installed all my own gas lines with no leaks and understand the dangers of leaks with natural gas.

Thanks
KO

 

[ForceFed70]

City/Line pressure varies quite a lot. But it should always be well above the regulated pressure in your home.

You can actually make your own fairly accurate water colum aparatus for measuring the pressure if you are curious.

 

[D.J.]

why not use a standard pressure guage?

 

[HoosierBuddy]

why not use a standard pressure guage?

The normal natural gas pressure for most homes is around 7 inches water column or about 0.25 PSI. They make pressure gauges that are in that range, but in my experience they are often WAY off on their calibration. A manometer is a good way to check pressure in that range.

At work, we have combustible gas indicators (CGI's) that have a built in digital pressure gauge that are very accurate too. I think that "bit o kit" runs about $1000 a unit though.

Phil

 

[Sureshot]

I say quit looking unless the heat goes out. Sounds like you are freaking yourself out.

 

[kbs2244]

Find something else to worry about.
European Banks.
Global Warming.
Overpopulation.
Something inportant.
Something you can do something about.

 

[koditten]

Those things get worried about as well. I'm an equal opertunity worrier

KO

 

[Milton Shaw]

I just saw the gas company install a new drop for a neighbor and they used a flow limiter at the tap on the main line at the street. They said the flow limiter kept the pressure about 1 psi in the line to the house so that if broken somewhere it would not be such a big leak. They also when they were leak testing the pipe at 100 to 115 psi they hooked a GPS leak detector on the air line to show that that location had been tested at 107 psi for the 15 minutes that is required. The Utility company just got hit with a $250,000 fine for a gas leak that blew up a house and killed a kid two years ago. That tap they used then was a "U"bolt type tap instead of a welded tap they use now. They have gone back and replaced all of the "U"bolt taps they had used with the welded on kind in the two years since the explosion.

 

[koditten]

Greaaat. Now I have to worry if I have welded tie ins or saddle clamps.

 

[HoosierBuddy]

I just saw the gas company install a new drop for a neighbor and they used a flow limiter at the tap on the main line at the street. They said the flow limiter kept the pressure about 1 psi in the line to the house so that if broken somewhere it would not be such a big leak. They also when they were leak testing the pipe at 100 to 115 psi they hooked a GPS leak detector on the air line to show that that location had been tested at 107 psi for the 15 minutes that is required. The Utility company just got hit with a $250,000 fine for a gas leak that blew up a house and killed a kid two years ago. That tap they used then was a "U"bolt type tap instead of a welded tap they use now. They have gone back and replaced all of the "U"bolt taps they had used with the welded on kind in the two years since the explosion.

The "flow limiter" of which you speak does not limit the outlet pressure to 1 PSI.

PHMSA regulations changed several months ago and now require new or replaced natural gas service lines to include an excess flow valve (XSFV). The valve acts as a self-resetting "fuse" in the gas service. If the flow in the service line exceeds the set point on the XSFV, it trips, cutting off almost all gas flow in the line. When it's in it's "open" state, it doesn't reduce pressure at all though. In fact, it doesn't reduce pressure in it's "closed" position either, it just limits flow.

Once it trips, it will bleed through a small amount of gas. This is necessary for the "reset" feature to work. Once the gas company gets the cut line fixed, the bleed allows the service line to repressurize. Once it does, the XSFV resets to the open position.

The XSFV will not normally trip if the service is only partially cut or if there is a break downstream of the meter/service regulator...as there won't be enough flow to trip it.

Phil

 

[redsky49]

The color of your flame will (slightly) vary from time to time based on environmental conditions and the quality of your gas supply.

More often, the flame color will change based on combustion quality/accuracy or lack thereof. This is why a burner check and service is worthwhile at the start of heating season.

Air supply, chimney, burner orifice(s), altitude, etc. are all factors, as are minor items such as uniformity of gas and air distribution, excess air and many other design factors.

A good rule of thumb is for a bright blue color with yellow tips just starting to disappear. Unfortunately, most residential burners are not adjustable to an ideal flame as they don't have any secondary air adjustments. Instead, just get as close as possible.

 

[fatboy99]

The "flow limiter" of which you speak does not limit the outlet pressure to 1 PSI.

PHMSA regulations changed several months ago and now require new or replaced natural gas service lines to include an excess flow valve (XSFV). The valve acts as a self-resetting "fuse" in the gas service. If the flow in the service line exceeds the set point on the XSFV, it trips, cutting off almost all gas flow in the line. When it's in it's "open" state, it doesn't reduce pressure at all though. In fact, it doesn't reduce pressure in it's "closed" position either, it just limits flow.

Once it trips, it will bleed through a small amount of gas. This is necessary for the "reset" feature to work. Once the gas company gets the cut line fixed, the bleed allows the service line to repressurize. Once it does, the XSFV resets to the open position.

The XSFV will not normally trip if the service is only partially cut or if there is a break downstream of the meter/service regulator...as there won't be enough flow to trip it.

Phil

A couple years ago they were widening a state highway in our service area. There was one of these XSVF valve for a 80 unit apartment complex and when they ran the bulldozer over the area of the valve it would trip killing the flow to the complex. The service men would shut off the main valve to reset then do 80 relights on the stoves,water heater's and furnace's on each unit They loved the over time

 

[koditten]

Red:

Thanks for the info, those are the things I am noticing with my flame pattern, I was not aware atmospheric conditions could change the flame pattern.

KO