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I have a 400 gal. propane tank buried in the yard that serves the house furnace & hwh. According to our propane supplier, the 1st stage regulator at the tank outputs 10psi. From the tank, it runs to the side of the house where it goes through a 2nd regulator (RegO LV4403 ) then to inside the house to serve the funace and hwh. Both inside appliances say their max inlet pressure is 0.5 PSI so I suspect since the LV4403's max output is 13"WC or 0.46 PSI, that it's set to it's max.

I bought a 6580/5500 watt dual fuel generator last year and had to run it on several grill sized bottles during an extended power outage. Since I have that huge tank in the ground I thought it would make sense to run a line off the pipes that already come into the house. The closest pipe to the back of the house (below my deck and where I want to locate the generator) was originally for a cooktop but is no longer in use. So I extended that line with black pipe out the back of the house to a shutoff and quickconnect.

My grill will light, but there's barely a flame - even with just 1 burner lit!

I have a sphygmomanometer gauge from an old blood pressure cuff that reads from 20 to 300 mmHG. While I don't think its accurate, it gave me some values for comparison. I hooked it up to the pipe I ran out of the house and it read 32mmHG. I then tested the grill supply line connected to a propane bottle - which include the grill regulator - and it read 35mmHG I also tested the supply line for the generator using a propane bottle - - again with the QCC1 & Regulator in line - and it read 43mmHG. So it seems that the pressure inside the house is less that what's required for either the grill or the generator.

My thought was to just tap into the 10 PSI line after the 1st stage regulator but before the 2nd stage and run a separate line through the house and out the back to a male QCC1 connector. This way I could connect the grill or the generator to that QCC1 and use their OEM off-the-bottle set-up (QCC1 female/regulator/hose) and thereby bring the pressure down from 10 psi to the correct pressure required for each.

So my question is basically - is it a safety issue to run propane at 10 PSI through my house? If it matters I'd make the run with a coil and not have any terminations or splices actually inside the house.

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  • Top of my concerns would be the ability of the tank to serve sufficient volume of gas. Notably, propane is stored in the tank as a liquid, but delivers as a gas. That means it must boil in the tank. In order to boil, it must absorb its latent heat of vaporization. A limiting factor in gas delivery is the ability of the tank to absorb heat from outside. If it can't, the liquid propane will get colder and colder until it refuses to boil anymore. And you get no flow. Oct 11, 2022 at 3:51
  • Thanks for the reply. The ingound tank was sized to serve a furnace, water heater, gas fireplace and cooktop. At this point it only serves the Furnace and water heater. Addtionally, the only time I'll be using the generator is when the power is out, and if the power is out I won't be using ANY of the other things. Also, they never fill up the tank completely which I assume is so there is always space at the top for the reason you give.
    – steveu812
    Oct 12, 2022 at 0:58
  • Instead of editing the question and title with the resolution, please follow the standards here and write up an answer (down below) indicating what the solution was (even if it was just "malfunctioning test equipment"), then click the check mark when the system will allow you to do so. This helps everyone to know that this question has a solution so nobody wastes time trying to answer, and others with the same problem know that there's a solution here for them to try.
    – FreeMan
    Oct 19, 2022 at 15:03

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It seems I was over complicating things and using a gauge that wasn't giving me accurate information.

Chatting with the generator manufacturer, they said that if I go directly into the generator the pressure needs to be between 11" and 13" water column or wc.

Doing more Googling - it seems that - with few exceptions - nearly ALL propane appliances are designed for that 11-13 wc range.

That said, the Char-broil help line told me that I MUST use a 20lb cylinder with their supplied hose/regulator combo, and that nothing else would work. I asked if they could pass along my question to a more technical person and she said she would.

Regardless, I bit the bullet and bought a 0-30" water column gauge - should have done this much earlier. The pressure at my quick-connect on the back deck is 12" wc. I then hooked up the generator this morning and it works just fine.

So it seems my original line off the stove feed out the back of the house is just fine.

We don't grill much so having to use the 20lb tanks is not a big deal but I'm hoping to find out why Char-broil seems to be different than other mfgs. who say you can connect to house propane. I'll edit this post again if I hear back.

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