Propane Firepit Question

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cartech

New Member
May 27, 2021
3
SF Bay area
Hi folks,

I have a 3/4" home-plex (buried 18" underground). One end to the other is about 12'.

I want to use it for a firepit (65K BTU) -- connected to the 3/4" riser with a 3/8" propane hose.

On the other end (about 12' away), I tried connecting a 20lb propane tank - 3/8" ID hose with the propane regulator that came with the firepit to the 3/4" riser.

When I open up the tank all the way and the key on the firepit I dont hear the hiss of the gas at all -- doesn't light up.


So my connections are ==>. Propane Tank --> Regulator --> 3/8" ID hose (6' length) --> 3/4" home plex line (12' length) --> 3/8" propane hose (5' length) --> firepit

Connecting the firepit directly to the propane tank with the included 3/8" ID hose with regulator works just fine.

What am I missing? Any ideas on what I can do to get the firepit working using the home-plex line??
Appreciate your help/advice. Thanks
 

cartech

New Member
May 27, 2021
3
SF Bay area
All lines clear?
Yes. I can see some gas coming out of the last hose (one that connects to the fire pit) - when I disconnect the hose from the firepit.

Wondering if the size of the hoses (3/8 to 3/4 to 3/8 ) has something to do with this or do I need a different kind of regulator?
 
Last edited:

Corey

Minister of Fire
Nov 19, 2005
2,627
Midwest
That large volume of pipe may be triggering the safety valve in your propane tank. If too much gas squirts out too fast when you first open the tank valve, a safety trips and shuts off the flow. This isn't an issue on an 18" section of 3/8 line, but probably tripping trying to fill 12 feet of 3/4.

The solution is to close the propane tank valve and close the fire pit valve. Wait 10-15 minutes for everything to reset. Then open the propane tank valve exceptionally slowly for the first 1/4 to 1/2 a turn. You want the gas to seep out and slowly fill that long pipe. This may take several minutes or more. Once the system is pressurized, you can open the propane tank fully.

Now you want to go to the firepit and open that valve. With all ignition sources extinguished, you probably want to vent that for a while to get the air/propane mix out of the lines (or the first start-up may be quite an event!). Now the firepit should operate normally. To shut down, you always want to close the firepit valve first, then the propane tank - not vice-versa. The idea being you want to keep the line pressurized all the time. Anytime the line needs repressurized (tank change, out of service for a while, etc) you need to repeat the 'slow seeping line filling' procedure.

Also, some tanks can be more sensitive than others...I had one which was very tedious to get going on ~4 feet of 1/2 inch pipe and others that just don't care and work fine no matter how fast they are turned on. If you're renting/exchanging tanks, each will have a different 'personality' though if you own one, you will have a good idea how it operates.
 
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cartech

New Member
May 27, 2021
3
SF Bay area
That large volume of pipe may be triggering the safety valve in your propane tank. If too much gas squirts out too fast when you first open the tank valve, a safety trips and shuts off the flow. This isn't an issue on an 18" section of 3/8 line, but probably tripping trying to fill 12 feet of 3/4.

The solution is to close the propane tank valve and close the fire pit valve. Wait 10-15 minutes for everything to reset. Then open the propane tank valve exceptionally slowly for the first 1/4 to 1/2 a turn. You want the gas to seep out and slowly fill that long pipe. This may take several minutes or more. Once the system is pressurized, you can open the propane tank fully.

Now you want to go to the firepit and open that valve. With all ignition sources extinguished, you probably want to vent that for a while to get the air/propane mix out of the lines (or the first start-up may be quite an event!). Now the firepit should operate normally. To shut down, you always want to close the firepit valve first, then the propane tank - not vice-versa. The idea being you want to keep the line pressurized all the time. Anytime the line needs repressurized (tank change, out of service for a while, etc) you need to repeat the 'slow seeping line filling' procedure.

Also, some tanks can be more sensitive than others...I had one which was very tedious to get going on ~4 feet of 1/2 inch pipe and others that just don't care and work fine no matter how fast they are turned on. If you're renting/exchanging tanks, each will have a different 'personality' though if you own one, you will have a good idea how it operates.

thanks for the details. I’ll try this today.