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LPG / Propane tank and valve sanity check

Yotota

Yotota

Truck nerd
Joined
Jun 6, 2020
Member Number
1870
Messages
1,302
Loc
SW WA
I have a handful of equipment running off propane:

Kitchen cooktop
BBQ
Space heaters

Up until now, 20lb BBQ cylinders have worked and even kept the cooktop running for 3-4mo at a time.


And now I have a 12kw portable generator. It will consume up to 1gal/hr of propane, and our outages up here don't last more than 2 days. But I'm planning to have extra capacity of course.


My initial thought was just get 8-10 more 20lb tanks and a storage rack but that idea kind of sucks and is expensive. Mainly the suck would be from swapping out cylinders every 5-6hr for the generator, or at best I could tee a couple together to get through the night.


My current thought is to buy a 420lb (100gal) tank such as this one:

flameking.com

420lb (120 gal) ASME Cylinder w/float gauge & relief valve Model #: YSN420ASME - Flame King

Flame King’s ASME-certified 420LB (120 Gallon) vertical steel propane cylinder is the perfect solution for homes and businesses that are powered mostly by propane. These cylinders are manufactured to ASME specifications in facilities that have a Quality Management System certified to ISO 9002...
flameking.com

Then replace the fill valve with a multi-valve that can dispense liquid propane such as this one:

LPG & NH3 – RegO Products

www.regoproducts.com www.regoproducts.com

And finally put together a fill hose that I can use to refill the 20lb cylinders I have here. Yes, I know how to fill cylinders. I would run the generator off the vapor service valve on the big cylinder and get up to 100hr of run time from a full tank.


Primary question:

That valve is designed for a 100lb cylinder (43-44" body height), and I don't see any reason it won't work on a 420lb cylinder (45-46" body height). Pressures are the same (because propane), the liquid dip tube length is right, and the threads may or may not need adapting but will work either way. The spec on the Rego valve is for 100lb cylinders due to the integrated pressure relief valve but the cylinder will have a separate relief valve anyway. Will this work?


Secondary question:

Does this idea suck, and does anyone have something better?
 
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Other benefit of the 420lb cylinder: I would have it filled by a service truck which is $1/gal cheaper, and I don't have to take a load of cylinders to get filled somewhere.
 
Oh and to be clear, I would order the parts and have the install done and tested by a pro.
 
Yotota said:
Other benefit of the 420lb cylinder: I would have it filled by a service truck which is $1/gal cheaper, and I don't have to take a load of cylinders to get filled somewhere.
Click to expand...
isn't there a delivery fee?
 
SomeGuyFromOlympia said:
isn't there a delivery fee?
Click to expand...

AK_F250 said:
And many want you to lease the tank from them and won't touch a privately owned tank.

I would call around to make sure you can find someone to fill it before going any further.
Click to expand...

Good call, and I already did.

I don't use enough to make a lease/periodic service plan worthwhile and I already found a local delivery company who is more than happy to fill any tank for $2.50/gal delivered. Most fill stations (gas stations, hardware stores, etc) charge $3.50/gal to fill tanks.
 
Why don't you just get an even bigger tank? You're already not going to be able to lift the tank and if you plan on refilling smaller bottles a larger tank would be beneficial. Like 250+
My 575 tanks have a valve on the bottom that I refill smaller bottles with. That's more of a novelty or something to have when you're in a pinch though.
 
Dan said:
Why don't you just get an even bigger tank? You're already not going to be able to lift the tank and if you plan on refilling smaller bottles a larger tank would be beneficial. Like 250+
My 575 tanks have a valve on the bottom that I refill smaller bottles with. That's more of a novelty or something to have when you're in a pinch though.
Click to expand...

I have to balance the cost of the tank and install with my actual use... I can move a 420lb tank here with a tractor, set it on a simple 36x36x6 concrete pad, and secure it to the side of the shop with earthquake straps. Easy peasy. But yeah, it doesn't have the bottom bung (huh huh he said bung) for liquid dump so I would have to add a liquid service valve.
 
^^ That.

I'd got 350 or 500 for the generator. Look up what the loaded burn is on the one you're buying. The 20kw generac I had at my old place I think would run for 6-7 days on a completely full 350gal tank....and how often is it going to be completely full when the power decides to go off for several days?
 
Yotota said:
I have to balance the cost of the tank and install with my actual use... I can move a 420lb tank here with a tractor, set it on a simple 36x36x6 concrete pad, and secure it to the side of the shop with earthquake straps. Easy peasy. But yeah, it doesn't have the bottom bung (huh huh he said bung) for liquid dump so I would have to add a liquid service valve.
Click to expand...

In that case I think you are on the right track for your application. I don't have any experience with that liquid valve but it looks cool and I would appreciate some feedback after you get it set up.
 
Muckin_Slusher said:
Pussy.
Click to expand...

:flipoff2:

For some dumbass reason, pipe threads and I don't get along. Maybe I'm too light on them? I try to get to the proper "turns past finger tight" spec and then they leak, then I tighten them more and they leak, then I pull them apart and add different combinations of tape/dope and it's still a 50/50 gamble if it leaks.
 
just use the pipe tape
crank it down until you're somewhat worried about the female fitting splitting
then it won't leak

btw, those 420s should already come with a combo valve
they likely won't have a liquid draw port though, I didn't really comprehend your post of what you're wanting to do with the filling cylinders and running the genset.
You can probably get one with a multivalve that just has a liquid draw service valve with no vapor service valve. Just make up some stupid dongle to toss a vapor service valve onto the 1-1/4" acme vapor return fitting for running your genset if it isn't one that'll take liquid.
The valve for a 100lb cylinder won't have enough flow through the safety relief valve for a 420lb tank.

most places give you a better rate per gallon if you're buying a few hundred gallons at a time, so really, a $700 used 500 gallon tank makes the most sense
 
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[486] said:
just use the pipe tape
crank it down until you're somewhat worried about the female fitting splitting
then it won't leak

btw, those 420s should already come with a combo valve
they likely won't have a liquid draw port though, I didn't really comprehend your post of what you're wanting to do with the filling cylinders and running the genset.
You can probably get one with a multivalve that just has a liquid draw service valve with no vapor service valve. Just make up some stupid dongle to toss a vapor service valve onto the 1-1/4" acme vapor return fitting for running your genset if it isn't one that'll take liquid.
The valve for a 100lb cylinder won't have enough flow through the safety relief valve for a 420lb tank.

most places give you a better rate per gallon if you're buying a few hundred gallons at a time, so really, a $700 used 500 gallon tank makes the most sense
Click to expand...

Thank for the killer info.

I'll be running the genset straight off this tank, so it needs regular vapor service. Then I have other shit around the property that will run on separate 20lb BBQ cylinders and I'd like to be able to refill those from the big tank when needed.

The 420lb cylinders I've seen have 4 ports on top - vapor service, fill, gauge, and relief. I would remove the fill valve and replace it with the Rego 8555DL multi valve that functions as a fill, liquid service with draw tube, and also a relief valve for a 100lb cylinder. But since I'll still have the 420lb relief valve the relief capacity would be met. I think. Maybe.

There is a mythical rare Worthington 420 that has the regular 4 as well as a liquid service port on the bottom, but none of the dealers I've talked to had ever seen one.

I'll confirm with the delivery company I talked to about rates for a 50-60 gallon topoff delivery versus a 200 gallon. Maybe the difference there will be the kicker.
 
Yotota said:
I would remove the fill valve and replace it with the Rego 8555DL multi valve that functions as a fill, liquid service with draw tube, and also a relief valve for a 100lb cylinder. But since I'll still have the 420lb relief valve the relief capacity would be met. I think. Maybe.
Click to expand...
that makes a lot more sense
 
[486] said:
that makes a lot more sense
Click to expand...

I chatted with an engineer at Rego, that valve is good to go for my application. The relief valve is for 100lb DOT tanks so it's a 375psi valve, and my 420lb ASME tank will have a 250psi valve. So while it's not a common use it will work.
 
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