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Upsizing Fire Pit Gas Line?

inmojoinmojo Member Posts: 3
We had a firepit put into our back yard, the gas line runs roughly 20 feet to the Fire Pit. I believe our line is a 3/4" line and we put in 3/4" pipe to the Fire Pit. I'm really displeased with the Fire that the line and burner are producing and was wondering what my options were, and had a few questions:

Would it be beneficial to have a 3/4" line run underground and come up at the fire pit through a 1 1/4" gas pipe, or would that not produce more gas at the pit?
Is my line actually a 3/4" line? It looks to measure at 3/4", but the Flex Hose coming out at the Fire Pit is a 1/2" line as far as I can tell. The contractor says we aren't downstepping and its a 3/4" pipe on the outside, but that the line is actually 1/2". I've attached picture of both the line from the house and the line at the fire pit.
Is it possible there is something wrong with the gas pressure at the Meter, or is the size of the fire coming out of a 30" stainless steel Fire Ring to be expected given our current gas line size? I've attached a few pictures below to hopefully help.

Line from the House:
Line at the fire pit:
Fire pit with valve fully open:

I'd appreciate any help I could get on this topic as i'm at a bit of a loss and am really disappointed about the results that the gas line is producing, it's a dinky fire that really couldn't warm up much of anything and am hoping to try to find solutions for the problem.



  • ZmanZman Member Posts: 5,995
    What is the make and model of the fire pit?
    The manufacture will have specifications for required btus and pressures.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ratioratio Member Posts: 2,561
    After you sure the fireplace is underperforming? It's my understanding that that style is more for looks than heat.

    That said, looks like ½" coming out of the house with a reducing (enlarging!) 90° on it, so maybe the problem is inside the house. There is or should be a sticker on the flex line that shows the max BTUH it can carry (it's a table, you'll need to find the right now & column). A quick test to see if it's indeed a flow issue is to take an inlet pressure at the gas valve with the burners off & with them on. A difference of more than ½ should be looked into.

    GordySteve Minnich
  • inmojoinmojo Member Posts: 3
    You're right its a 1/2" line from the house, and they stepped up to run the line under ground, then reduced it again to 1/2" at the Fire Pit. It's a custom built fire pit not a pre-fab, the only thing thats controlling the flame is the line from the house, 20' to the pit, and the pipe coming out of the ground.

    It sounds like I should call the gas company to see about testing our gas pressure, so i'll do that today, thanks!

    Secondly, would it be helpful at all to ask them to not step back down to 1/2" at the Fire Pit and instead keep it at 3/4" even though the line coming off the house is a 1/2"?

    Thanks for the help and the prompt replies!
  • JellisJellis Member Posts: 208
    I would think it easier to increase your gas pressure in the line to the pit and put a regulator at the pit to reduce the pressure again. 2psi from the house to the pit and 11"wc at the pit would give you around 225,000 BTU's. Your current setup which likely has 11"wc gas pressure running from your house to your pit only supplies 113,000 BTU's (assuming a 1/2" pipe at 20' run)
    These changes would be made by your gas supplier.
  • DZoroDZoro Member Posts: 1,035
    Custom built, by who? Specs? Somebody must have some info on safety/performance.
    LP or Nat gas?
    The gas piping you have has great capability, many BTU's available, but distribution, performance and most of all, safeties should be documented by someone.
  • GordyGordy Member Posts: 9,523
    Fire pit rings are pretty simple really. I wouldn’t expect much more than what you are getting. It’s not going to be like a camp fire.

    Think about a BBQ grill flame. That’s about 60k depending on grill size.
  • ratioratio Member Posts: 2,561
    All the gas pipe that the gas flows through contributes to the volume you can get at the end of the pipe. If, for instance, that ½" pipe in the house is 60' long and has 15 90°s in it, that could be your problem right there. If the problem is there, then you could run 2" out to the fire pit & it wouldn't change things.

    Where's the installer? I would have expected him to at least eyeball the gas supply lines. He should also be able to take pressure readings at the gas valve, to see what's going on.

  • ZmanZman Member Posts: 5,995
    We have a local company that makes "Custom" firepits. No safeties and no calculations on the orifices.

    If you can figure out the size and count of the orifices, you can work out the required BTU's. From there you can size the gas lines.

    Right now you are just guessing. You really don't know if you have too much or not enough gas.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • inmojoinmojo Member Posts: 3
    edited December 2018
    Jellis how would I go about increasing the gas pressure in the line? Is that something i'd have to contact the local gas utility about?

    Sorry DZoro what do you mean to 'specs'? I can ask the contractor and see what he gets back to me with, but it's a Natural Gas fire pit.

    Took a few more pictures:
    Sticker on the pipe that goes underground:

    Lines coming out of the ground to the burner:

  • ratioratio Member Posts: 2,561
    That does look long and skinny, but without knowing how many BTUH the fire pit consumes we can't really tell for certain. The back side of that sticker on the end that's harder to get to tells you how much gas it can flow. Is there a nameplate or a sticker of some kind on the fire pit? Sometimes you can guess at the size of the burners by the model number.
  • GordyGordy Member Posts: 9,523
    edited December 2018

    I don’t know your brand, but this gives an idea of the requirements.

    435,000 btus for a 30”. I highly doubt your gas meter is even big enough to get the full output.........
  • JellisJellis Member Posts: 208
    Your gas supplier would handle any pressure changes. You should not attempt this unless you have proper testing equipment and know what you are doing.
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