Outdoor Fire Pit Gas Psi Noise - need help pls

[embo]

First time post - Recently added a new gas line separate from the line running all the appliances in the house. Tapped into the service side of the meter using a Tee. Out of the gas meter, we have 3/4 inch suppling both the appliances in the house on one line and also one line going directly to the fire pit. About 1.5 ft of 3/4 inch line from meter then 1 inch line for house appliances. That same 3/4 inch line from the meter uses a tee and it changes into a 1 1/4 inch line to the fire pit. about 1.5 ft before fire pit connection, line goes from 1 1/4 to 3/4 through a Key Valve and about 12 inches of 3/4 to fire pit ring.

Issue is when the key valve is turned on, slowly, we hear the gas flowing through the key valve and it gets louder the more we increase the gas. Until finally about 3/4 full throttle, the noise starts to dissipate some. Full open and the noise is almost gone. Wondering how to reduce that noise at the lower settings. I believe the noise simple the pressure of the gas flowing through the key valve. The more closed the valve is the more restricted the gas therefore making more noise. Should there be a regulator installed to reduce the gas psi but keep the volume of the gas the same? Is that possible.

Fire Pit ring is 300,000 BTU. Hopefully I have described this enough that you pros can help me get this figured out.

Thank you in advance for any help/suggestions.

 

[Jadnashua]

It's a little hard trying to figure out what you have so a picture or a diagram would be useful.

Wherever you patched into the gas supply must be after the pressure regulator. If it was before, you may have damaged the regulator in the new unit.

Technically, at least around here, while you can turn the main gas off in an emergency, the gas utility is supposed to turn it back on. Since that valve doesn't normally get used much, it can leak, and may need some maintenance to seal properly after being moved.

 

[Sponsor]

 

[embo]

It's a little hard trying to figure out what you have so a picture or a diagram would be useful.

Wherever you patched into the gas supply must be after the pressure regulator. If it was before, you may have damaged the regulator in the new unit.

Technically, at least around here, while you can turn the main gas off in an emergency, the gas utility is supposed to turn it back on. Since that valve doesn't normally get used much, it can leak, and may need some maintenance to seal properly after being moved.

Interesting you ref the gas meter being shut off by the gas company only. Not sure but if there was an issue and I couldn't get to the appliance shutoff for whatever the reason, then the only shutoff I have left is the valve on the supply side of the gas meter. As I understand it, the homeowner is responsible for the service side (the side from the gas meter to the house) and the gas company is responsible for the supply side (gas company to the house). Sorry for being so basic about it but I need to make sure I understand how things work and it's new terminology for me as well.

Not sure if there is supposed to be but there is not a shutoff valve on the service side of the meter.

In the picture you can see the meter and the current line (one) 3/4 to 1 inch line. Then you can see where the 1 1/4 inch line for only the fire pit is. It has the pressure gauge on it. This line was added or a tee was used so the meter now feeds both the line that is connected in the picture and the line that has the pressure gauge on it. A tee was installed where the 90 elbow was (horizontal to vertical) on the original line. The red line represents the current connection. Hope this helps.

I believe the gas meter and regulator at the house is good. Nothing seems to be working incorrectly. It is at the fire pit end where the issue is. The sound is the only issue. It's like there is a lot of psi flowing through the key valve at the fire pit which is makin the noise. I have uploaded a second picture of the fire pit connection PRIOR to the line from the key valve to the center of the pit being installed.

Hope this helps clear up my explanation. It is at this valve that the sound is the issue. Again, from the valve it's 3/4inch to the center. I didn't use a flex line due to hearing about whistling issue and I had the 3/4 inch available.

 

[Fitter30]

Seeing a regulator at the meter i don't have any idea what your gas pressure is could be 2 lbs or 7 ".Most burners are design for 3.5" needing a inches to inches regulator for the burner. Opening up a gas valve with a open pipe will be scream.

 

[Jeff H Young]

never thought about it but is a 1/2 inch log lighter valve supposed to flow 300,000 btu? maybe once the burners installed itll have enough back pressure so it wont be noisy also is arow pointed the right way?

 

[embo]

hmm.. you guys know more than me that's why I am asking on this forum but the key valve has 3/4" male ends so I assume the body of the key valve is also 3/4" but is that correct. As far as the arrows in the correct direction...Yes they are in the pointing in the correct direction.

I did talk to a fire pit company and they suggested first installing an orifice between the pipe and the gas fire ring, right where the ring attached to the pipe. It will be drilled out for a 300,000 btu ring. They said this is the cheapest possible fix. Then if that doesn't do the job they suggested a regulator install somewhere before the key valve. But they suggested this orifice first due to cost. They sell the same fire ring I have in a kit that includes the orifice and regulator if you get the kit instead of just the ring. Not knowing about this possible issue I purchased only the ring. But I was told not always is the sound issue and issue.

BTW... the sound is WITH the fire ring installed so I guess that means there isn't enough back pressure from the ring to reduce the sound.


Here is what it looks like in the pit les the plate that holds the lava rock and the actual fire ring. But the ring attached directly to the pipe here in the picture.

I really appreciate any of you looking at this issue and giving me some suggestions.

 

[embo]

Seeing a regulator at the meter i don't have any idea what your gas pressure is could be 2 lbs or 7 ".Most burners are design for 3.5" needing a inches to inches regulator for the burner. Opening up a gas valve with a open pipe will be scream.

This is what my current gas meter says

And I tested to see if the meter could handle having the fire pit on, stove on in kitchen and fireplace heater on at the same time and there is a reduction on the stove if the fire pit is turned up. So the gas company is going to come out and verify what I see and then probably will be upgrading out meter or change the regulator setting or something like that to allow for all appliances to be able to run correctly. I thought this would be the case and tried to get them to upgrade before the pit was installed but they wouldn't do that. They wanted the pit installed first and then would if needed.

 

[Jeff H Young]

I can tell your meter is 275 cfh fire pit alone will just about max it out. but thats nothing to dowith your noise. That much volume going through the valve is making noise Ive noticed noise on log lighter valves befor, never really adressed it. When I mentioned the back pressure I was thinking that an open pipe would be allowing it to run through valve so fast it would cause the noise. I think that big burner allows such speed similar to an open pipe . Im not an expert on these I think Id contact the valve manufacture and inquire, not so much for concer but annoyance and just gotta know why. let us know if you find anything out

 

[Bannerman]

The gas regulator at the meter indicates the regulated gas output pressure will be between 6-8 inches of water column. The fire pit burner could be and is likely designed for 3.5" IWC (1/8 psi) input as the maximum.

An orifice nozzle, is to restrict gas flowing to the burner to the correct maximum output, but that will be based on the correct gas input pressure. As your fire pit supplier offer an orifice and regulator kit for that model, that suggests those components will be required.

 

[embo]

After reading comments and talking with other fire pit ring suppliers, it might be the orifice and/or the regulator will do the trick. On company supplies the orifice with the ring when you buy it. Anything over 300 btu is supplied with this orifice it seems. So I will know this Thursday or Friday when the part comes. Will let you guys know what I find. Maybe there will be more suggestions in the meantime that I can look into just in case this orifice/regulator thing doesn't work out. Thanks

 

[Fitter30]

Heres a orfice chart to btu.
https://www.google.com/url?sa=t&sou...FjARegQIAxAB&usg=AOvVaw1REt5EgdbMjTOU6QVA274G

 

[Jeff H Young]

The ones I saw didnt have an orofice but had to just barely crack valve . show picture of the parts you get please like to see it havent seen one on fire pit but havent really seen that many in detail. ive built them just like you did it was their kit and like i said had to just barely crack valve

 

[Jadnashua]

An orifice does two things:
- because of the restriction, accelerates the gas flow to get it where it needs to go, and because it's short, doesn't restrict the volume that much
- helps to manage the air/fuel mixture for the burner. On something like a fire pit, it could mean the difference between a blue flame or an orange one

 

[embo]

An orifice does two things:
- because of the restriction, accelerates the gas flow to get it where it needs to go, and because it's short, doesn't restrict the volume that much
- helps to manage the air/fuel mixture for the burner. On something like a fire pit, it could mean the difference between a blue flame or an orange one

Sounds like this would make the flame burn more efficiently. I did notice quite a bit of soot on the burner the other night and the flame stays pretty yellow so it might not be burning as efficiently as it should be. So we, you guys with you suggestions and my leg work might be on to something. I really appreciate the help. Waiting for the orifice to arrive and will install and report back. Thank you

 

[Jadnashua]

Soot implies excess fuel...the orifice should balance that out if it's sized properly.

 

[Jeff H Young]

it needs more than an orifice to burn proper. those fire pit rings just have holes. unlike a burner on a stove or a furnace there is no opening for air to enter. So Im thinking there needs to be more to it.. not just a orifice it needs air to enter as well a venturi. thats why I want to see pics of what they send you

 

[embo]

So I installed the Orifice they sent and it does cut down on the noise pretty significantly. But as I suspected the flame was reduces a little too. Basically it's allows me to open the valve up more and this reduces the noise of the gas flowing through the valve and also there is some noise reduction simple from the fact that the hole in the orifice is smaller then the end of the 3/4" pipe therefore not allowing as much noise to get through. But we will keep it like it is for now and see if we like it as is. Here is the orifice they sent. Hole was drilled for a 300,000 btu burner ring.

I have another thought I would like to put out there to you guys and see what you think. Per regs I have to have a shutoff valve with in I think 5' of the fire pit. We have the key valve well within that limit. I am think about installing another valve upsteam of the fire pit farther way. We are adding on to an existing deck and the supply line for the deck goes under the deck, then get buried before popping up into the fire pit. I could install a valve right at he edge of the deck that would be about 25' farther away from the fire pit via piping not actual distance. The actual distance from the pit would be about 10'. So my thought is to leave the key valve full open and is there for regulations but use the valve I would install on the edge of the deck as the main "regulator" for how big a flame we want. Thinking the sound of the gas passing over the valve would be so much farther from the pit that it would deaden the sound significantly and I would then be able have a bigger flame.

So key valve full open and valve about 25' prior to fire pit via the pipe distance for control. Would that reduce the noise down or ?

I liked the ability to have a huge flame when we didn't have the orifice installed but the sound was not good. So we would rather have less sound and a little less on the full open flame size but would rather have full huge flame and less sound. Hope this makes sense.

What do you guys think?

Also with the orifice installed I have the key valve opened up a bit more for the same flame height as with out the orifice but more of the fire ring holes are fuller with flame which is a good thing.

 

[embo]

To help visualize what I was saying before. First picture is what is basically the current gas line from under the deck to the fire pit. Yellow is existing line.

This is looking from under the same deck but the red pipe represents what I as thinking of doing. Running the line over to the edge of the deck and then having another key valve that we actually control the flame with and then it goes back and connects into the existing line. So the actual valve that would be opening and closing the gas to the pit would be this one. The other at the fire pit would be just for legal issues and another way to shut the pit down if needed. The valve installed on the deck would be about 12' from the fire pit.

 

[Bannerman]

Perhaps I am missing something. Where is air mixed with gas prior to the burner?

In my earlier comment, I anticipated an air mixture control would be included in the kit with the orifice and regulator.

Is this controlled with only a manual valve? Where is that orifice installed, and how is the air mixture controlled to obtain a clean blue efficient flame?

 

[Jeff H Young]

I though about this after I posted a few days ago a nice clean burn isnt going to look like a natural fire arround rocks or fake logs. So maybe thats why it dosent mix air