Piping for gas fire pit


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Old 12-08-18, 10:00 AM
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Piping for gas fire pit

Want to install a gas fire pit that needs 250,000btu max and needs 3.5-7" wc
Meter is 250,000btu capacity set to 7" wc.

I had the builder put a stub out in the patio which I now know he only used 1/2" pipe and is a 50' run from the meter. (My fault for not specifying the size but I told the builder this would be for a fire pit and he still went with 1/2")

I extended the stub out to where the fire pit is and they used 3/4" pipe for 50'.

I am getting very weak flames (about 4"). My question is would there be any benefit to having the meter size increased, or am I limited by the small piping that the builder used off of the main line?
Does it matter if the 3/4" piping comes after the 1/2" piping or do I still calculate everything the same?

From what I see I would really need a 1 1/4" line along the 100ft run to make this work correctly, but that will be big $$ to fix.
 
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Old 12-08-18, 10:29 AM
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Welcome to the forums.

That first 50' of 1/2" pipe has you reduced to under 50k right from the start.
Is that a dedicated gas service just for the firepit ?
I'm not sure if you could raise the pressure at the meter end in order to overcome the deficiency and then reduce it at the pit. You are correct though..... 1-1/4" is good for 266k at that length.
 
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Old 12-08-18, 10:34 AM
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No it is not dedicated- that 1/2" comes off of the main line used for the house. So I think the pressure reduction has to remain at the meter. I just didn't know if having the gas company up the size would really have any effect.

Of note is that I get a loud whistle at the fire pit now when the valve is full open, this leads me to believe I am getting high pressure right now just not enough flow rate to get high flames?
 
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Old 12-08-18, 10:40 AM
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Flow and pressure go hand in hand. You can't have one without the other.
Technically you need a bigger meter too.
It needs to be large enough to supply all loads that could be on at the same time.
 
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Old 12-08-18, 11:10 AM
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Do you think I could make it work if I got the larger meter and pressure up to 2lb and then put reglators on the individual items? Would that be cost effective you think? I only have a dryer, tankless water heater, and stove top on gas in addition to the other long line that goes to the firepit/grill.

I could do something like regulate down to 7" wc after the branch which would get everything except the outdoor line. And then at the firepit regulate down to 7" and then at the grill I could regulate down to whatever that needs.
 
 

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