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How to go from 100# female POL to 3/4 inch NPT

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gotgas
gotgas Member Posts: 75
On my back deck I have a commercial 36" griddle and a commercial flame broiler instead of your standard grill. These are NSF rated propane restaurant appliances. They both take 3/4 inch NPT. Both draw 90000 BTU at Max. To provide propane to them I have a 100 pound cylinder. It has a female POL connection.

With the appliances I have 2 quick disconnect kits.. Both are like this: https://www.therestaurantstore.com/items/446156

I was going to use something like this for the conversion: https://protanksupply.com/shop/fittings/brass-fittings-fittings/female-pol-x-14-mnpt-2/

From that I was going to go into a brass 3/4 inch Y and then hook the quick connect directly to the Y.

I have done a fair bit of gas piping before, but I have never gone from POL to NPT. Is there anyone who has done anything like this? Anyone who knows if this is a good idea? I appreciate any help you can offer.

Comments

  • JUGHNE
    JUGHNE Member Posts: 11,089
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    What is the pressure in the 100 lb cylinder on a 100 degree day and then on a 60 degree day?

    As you might imagine it can vary with the amount of fill in the tank.

    You need a regulator at the tank. It will connect to to the tank with a pigtail for that purpose.

    There is a reason for these weird fittings....to save your life.

    For that much load you may need a household size reg. 2 stage perhaps.

    Look at your grills, what is the recommended gas pressure input?
    If you hook that up without regulator(s) the only thing you might barbeque is yourself and your house/deck.

    Needs more study and get advice from an LP company. They can sell you a regulator for that load.
    PC7060
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
    edited July 2022
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    POL to the tank with a proper size regulator on the other end of the POL fitting.

    NEVER CONNECT A TANK TO AN APPLIANCE WITHOUT A REGULATOR BETWEEN THE TANK AND THE APPLIANCE.

    Let me say that louder to be sure you heard me

    NEVER CONNECT A TANK TO AN APPLIANCE WITHOUT A REGULATOR BETWEEN THE TANK AND THE APPLIANCE.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    PC7060Solid_Fuel_Manrick in Alaska
  • gotgas
    gotgas Member Posts: 75
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    Thanks for the feedback.  I should have mentioned in my initial post that both appliances have a regulator at the appliance.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
    edited July 2022
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    The appliance regulator is a secondary regulator. You need a primary regulator between the tank and the secondary regulator in the appliance

    You can check the regulator specifications by looking up the part number of the appliance regulator. The appliance regulator will stabilize the pressure that enters the appliance that is connected to a "House Piping" that may have many appliances connected like a heating boiler of furnace and a Clothing dryer and a water heater. or in the case of a commercial "House piping" system other cookers or fryers or boilers that are connected to the same piping system. As each appliance turns on and off the house piping changes pressure. The primary regulator at the tank changes the high pressure tank to the lower pressure house piping pressure. You may want to watch this video. it explains the difference between House Line regulators and appliance regulators

    https://www.youtube.com/watch?v=nEtyvxITBWQ


    You don't want the tank pressure inside those appliance connectors. That is mucho dangerous. Depending on the amount of liquid in the tank and the ambient temperature around the tank, you can expect the pressure of the LP Gas leaving the POL Valve to be between 100 to 200 PSI. Your appliance works at less that 1 PSI gas pressure. Depending on the tank and piping arrangement, you want to connect the POL valve to a regulator to reduce the pressure to those appliance connectors to less that 2 PSI. The appliance connector will reduct that pressure from 2 PSI to the less than 1 PSI required for the appliance burner to operate properly.

    If you depend o n the Appliance Regulator to reduce the 100 to 200 PSI gas to less than 1 PSI, you will find yourself replacing appliance regulators on a regular basis (only if we don't read about the explosion in the news)

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    rick in Alaska
  • JUGHNE
    JUGHNE Member Posts: 11,089
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    Can you see the input pressure for those regulators?

    And how certain are you that this equipment is set up for propane....much different animal than NG.

    You will still need a regulator at the tank.

    Again, run this by a LP supplier....you are his customer.
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
    edited July 2022
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    I Hope that this @gotgas doesn't do anything stupid @JUGHNE. But we did our best. I'll bet the appliance regulator is rated for a maximum inlet pressure of 2 to 5 PSI. If he connects it directly to the tank pressure, someone may see some major fireworks at his first cookout!

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    JUGHNE
  • gotgas
    gotgas Member Posts: 75
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    Thank you all, especially Ed Young. Great info. I did not know about the line regulator. I think you all kept me from making a huge mistake.

    These were both in service on my deck before I moved. They came off a pair of 120 gallon propane tanks that provided lp for these, a furnace, and a water heater. The appliance regulators are both 1/2 PSIG.

    I live in a remote area and it will be weeks before I can get someone out. I was hoping to have this up and running prior to that. The work I have done before was under my plumber on my house running and assembling the black steel pipe from the manifold to the appliances. He helped and checked all my work, but we did not get into anything from the tank.

    It sounds as if I should just wait. Is there any way I can do this safely? I do my own electrical and plumbing, all with permits and inspected. I have completely wired and plumbed several houses, having been taught by an electrician and plumber. I know gas is different though. Is this something that should not be messed with?
    EdTheHeaterMan
  • hot_rod
    hot_rod Member Posts: 22,341
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    Where do you get the tanks filled? If you go to a propane dealer they often have the proper regulators at their shop and on their trucks for 2 stage systems. Take the data from the grills.

    Any chance both will be full fire ever? Often? If so the regs size for that load. Keep in mind how long that size tank @ 23 gallons, could supply both grills running, 180,000 BTU/ hr. have a second tank so you don't run dry mid meal :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • JUGHNE
    JUGHNE Member Posts: 11,089
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    There were double 100 lb tanks with auto change over, never messed with one.
    Many people just had the 2 tanks and did the change over manually.
    I believe the two tanks used the same regulator.
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    You'll need to size the gas line for the connected load and the distance from the tank to the appliances. 

    Generally 90,000 btu is easily handled by an intragal twin stage regualtor, which is ALWAYS at the tank. Then it is all low pressure from there. The pipe will need to be sized based on distance and total connected load. With propane you can use soft copper tubing which goes up to 5/8" if that will serve your purposes. 

    This line needs to be coated gas (yellow) if you intend to bury it in the ground if that is a consideration. You will need a listed outdoor gas appliance connector with a quick connect. I did this to my own grille. I run it off my 500 gallon tank. Again I am licensed and I own the tank. The gas company, still inspects my work to have it on file. 

    That gray line is rated for NG/LP and 1/2psi....or 14" water column. 

    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • gotgas
    gotgas Member Posts: 75
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    Thanks again for all the help. I think I am going to reach out for some help locally. This is beyond my knowledge. Glad you all helped me to realize that. You probably saved me from making a big mistake.
    JUGHNEDave CarpentierSolid_Fuel_ManEdTheHeaterMan
  • gotgas
    gotgas Member Posts: 75
    edited July 2022
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    I would like to revive this thread for a little more advice. I have not been able to line anyone up to come up until late fall, which means no grilling all summer. After doing a lot more research, this is what I have come up with and I wanted to run it by all of you:

    1. From the tank to the regulator a 12" POL to POL pigtail.
    2. A twin stage regulator, this model: https://www.amazon.com/gp/product/B01NCU75R4/ref=crt_ewc_title_srh_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER
    3. From that into a 3/4 gas pipe nipple
    4. Gas pipe nipple into a 3/4 T: https://www.lowes.com/pd/Mueller-Proline-3-4-in-x-3-4-in-dia-Black-Iron-Tee-Fitting/3418950
    5. Each end of the T is connected to 3/4 Regency 600psi gas shutoff via a 3/4 x 3/4 gas pipe elbow
    6. 48" Regency tube connected to elbow: https://www.therestaurantstore.com/items/446156
    7. Tube runs into Quick Disconnect (same kit)
    8. Disconnect connects to swivel connector
    9. Swivel connector goes to 3/4 x 3/4 elbow
    10. Elbow connects to appliance.

    That is my plan. All threads have 3-5 wraps of yellow ptfe gas line thread sealant tape. Couple questions:

    1. Does all of this make good sense? Any improvements you could suggest?
    2. Tape only or tape and No. 5 Pipe sealant?
    3. With the multistage regulator and only 48" of pipe, do I still need to appliance regulator?

    I would like to be able to grill this summer, but also to not blow myself or my neighborhood to small pieces. Any advice is appreciated.
  • ChrisJ
    ChrisJ Member Posts: 15,857
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    I wouldn't recommend tape especially if you're not experienced.

    Megaloc dope is what I usually use because it's easy to work with.
    Loctite 5117 pipe joint compound seems very forgiving and good at sealing leaks, but it's messy an you can't get it in some states.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • gotgas
    gotgas Member Posts: 75
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    ChrisJ said:

    I wouldn't recommend tape especially if you're not experienced.

    Megaloc dope is what I usually use because it's easy to work with.
    .

    Thanks for the tip. I can get this at the local Lowes.

  • hot_rod
    hot_rod Member Posts: 22,341
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    Yellow is double density tape intended for gas piping id, if you can find it.
    Dont wrap the tape off the end of the pipe or fitting or you may get shards inside the piping.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • gotgas
    gotgas Member Posts: 75
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    Thanks Rod. Does my plan seem sound? Do you see any glaring errors? I appreciate your expertise.
  • JUGHNE
    JUGHNE Member Posts: 11,089
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    I would say that you need the appliance regulators.

    The tank regulator(s) keep the pressure adjusted for the piping.

    The appliance reg takes that fairly stable pressure from the piping and fine tunes it down to what the appliance may need.

    Furnaces, water heaters and many appliances have a pressure regulator built into the actual gas valve.
  • hot_rod
    hot_rod Member Posts: 22,341
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    The reg in that pic doesn’t look correct. Seems it is a single stage and no POL fitting? Here is what I have, got it a HD 160,000 I believe
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    @hot_rod that looks like a DOT rated twin stage reg to me. Especially with rubber hose coming out of it.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • gotgas
    gotgas Member Posts: 75
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    @hot_rod that looks like a DOT rated twin stage reg to me. Especially with rubber hose coming out of it.

    I think that is an RV multistage. The one I sourced is for 250psi and 1,000,000 btu. I think it is the correct one for this application, maybe a little oversized since my max draw is 180,000 btu. I could be convinced otherwise though, since I am a newbie to this end of it.
  • gotgas
    gotgas Member Posts: 75
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    JUGHNE said:

    I would say that you need the appliance regulators.

    The tank regulator(s) keep the pressure adjusted for the piping.

    The appliance reg takes that fairly stable pressure from the piping and fine tunes it down to what the appliance may need.

    Furnaces, water heaters and many appliances have a pressure regulator built into the actual gas valve.

    Will do. I have the appliance regulators, so I will add them to the setup.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
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    Yes the regulator you selected looks like it will work. The regulator that Hot Rod showed in his picture is for a smaller appliance or only one of your appliances. It says it is two. stage but that may be internal. The one Hot Rod shows is actually 2 different regulators all in one cast aluminum housing. Very popular for Larger Gas Grill application or for hot roof torches. I have the same one.

    Your plan is sound.

    You can use Teflon tape however there is a wrong way to use it. Everyone will tell you about applying it clockwise. However there is another thing that is just as important. Don't go over the the edge of the pipe. Leave the first thread exposed. This video explains it the best. He is pretty detailed (long winded) but at about 4 minutes into the video, he gets to the point. https://www.youtube.com/watch?v=KJoO87dW30U

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    gotgas
  • gotgas
    gotgas Member Posts: 75
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    Thanks Ed! The chance of a mushroom cloud being in my immediate future is dropping considerably. Thanks to all for the help.
    EdTheHeaterMan
  • mattmia2
    mattmia2 Member Posts: 9,838
    edited July 2022
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    If you click on the gear in the video you can play it at 2x
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
    edited July 2022
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    I'm surprised the LP supplier won't help you sooner. My father (in the fuel oil business) told me that I had to keep those burners running. Can sell oil to someone with a broken (or in your case not connected) burner!

    I just don't think that there is that sense of urgency in the younger work force... I could get very political here!

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?