Solving the "Dual Tank Auto Change Over w/HP Regulator" Problem

Discussion in 'Propane - Got Gas' started by kenquagliana, May 5, 2020.

  1. rabird

    rabird Howdy!

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    you have a leak? you lost 1 lb operating nothing? you'll need an accurate scale to the fraction of an ounce. 20K furnace ~ 1lb/hr (no cycling off).
     
  2. mk4

    mk4 Member

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    this is hp - tee - lp.
    the lp is a single stage
     
  3. rabird

    rabird Howdy!

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    mk4, you can find more set ups like that in the parts book for coleman pre ???

    https://colemanpopupparts.com/pages/parts-books

    dropped hp all together 05-08 as code did not allow, before 05 there was no mention of hp in code, 08 they added language to allow hp, 30psi max regulated within 60" of cylinder.
     
  4. kenquagliana

    kenquagliana Member

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    Hi Rabird. Thanks. I took the tanks back off, weighed them again and repeated the process. They remained unchanged with both valves left open, no appliances running. So, no leak. My scale only registers to the half pound....obviously not that accurate. But I guess when I first installed the regulator and tanks and opened the valves, the camper drew enough gas to register that drop.
     
  5. kenquagliana

    kenquagliana Member

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    Okay All, Raybird finally provided the reason why check valves won't work. They didn't. If evaporation rate is the same, pressure will be the same. It was obvious, actually, in hind sight!! It was something I had to see and learn for myself. After an hour or so of running the HP stove off both tanks, they began to equalize. The Primary gained .5 lb's!! All the check valves in the system had no effect.
    So, I'll now go to plan "B" as suggested by Spridle: Putting in a manual ball valve in the bypass to isolate the tanks. This way, using / setting the ball valve and reserve tank valve (on/off) as required when using the HP stove, I can manage the Primary tank usage (to empty first) and facilitate the auto change over. The real benefit, is not having to physically switch the tanks when the primary tank empties - Just turn two valves and run off the reserve until the Primary can be refilled. I think this is the best solution (so far) to having a functional auto change over system for set ups having a separate HP regulator. Once I retrofit the bypass piping, I'll revert with the final drawing, photos and parts list. Thanks for everyone's input. Ken
     
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  6. Aladin Sane

    Aladin Sane I'd rather be camping

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    What I did was put a tee in the line coming from one tank before my switching regulator. I run off of this tank, and think of the second tank as a reserve for running the furnace over night. If my primary tank runs empty, I lose hp capability until I switch tanks or refill the primary. It works well for me. I cant see any advantage to keeping the bypass even with a ball valve in it.
     
  7. mpking

    mpking Well-Known Member

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    Just to be devil's advocate... how is that different than turning off the secondary tank from it's own shut off knob?
     
  8. Spridle

    Spridle Well-Known Member

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    Both on and full with the bypass shut off it will work as a normal dual tank auto change setup and feed the HP stove from the primary. If the primary tank runs dry overnight it will switch as intended and continue its duties. If the HP stove is needed with the primary tank empty then the bypass can be opened to back feed the HP regulator. The stove will still go out mid cooking, but the bypass brings it back online without physically swapping tanks around. My only question is if the one tank might actually try to fill the other. I would not think so, to get the liquid out you gotta turn the tank upside down.

    For myself I'd rather just keep the plumbing clean and be faced with swapping tanks for the HP stove. That's a lot of extra fittings that I'd just rather avoid. I have a mild phobia of things burning up and blowing up though.
     
  9. kenquagliana

    kenquagliana Member

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    Spridle, agreed on all. This seems to be the NEXT best way IMHO. That’s how I’m proceeding. I have no fear of any “blow ups”. I’ll just need to remember to close the bypass valve after cooking off the Primary tank and open the reserve tank valve before having too many drinks and retiring for the evening!!! FWIW, based on my tests, The Primary won’t backfill or equalize if I remember to close the bypass valve after cooking. I’ll be trying this set up this week and revert with my results. Now I have to build it!! Regards
     
  10. Sjm9911

    Sjm9911 Well-Known Member

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    This sounds like a lot of work for this. You cant just put a spliter before the regulater and feed the HP line directly? Then no need to turn stuff off and on all the time, the changover should work fine as long as you draw from the secondary bottle. Or am i missing something.......
     
  11. Bowman3d

    Bowman3d Well-Known Member

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    Mount a 3rd tank just for the outside grill.... problem solved!

    edit: my little laughing emoji didn’t post...
     
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  12. kenquagliana

    kenquagliana Member

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    Bowman......I always carry extra propane and the fittings to connect directly to the HP stove. That wasn't the mission!! Sjm9911......One negative possibility is if you constantly run the HP stove off the secondary or reserve bottle, you could deplete the reserve BEFORE the primary, leaving little , or no reserve gas when the changeover occurs. The goal, in my mind, was to find a way to deplete the primary tank first. This is now manageable.
    Last time I checked, anything worth doing requires a little pain. I built it, it works, and I learned some things along the way. I don't consider being aware of your propane system's status, and turning a valve or two, to be such difficult things. The cost was not a factor. I consider the project's time, "time well spent". Do what you will, but If you want a manageable auto change over system W/HP regulator, have the time, the money and some presence of mind, I state again....this works!! If anyone wants to know what it takes to make it, PM me.
    Regards, Ken
    IMG_2627 2.JPG IMG_2626.JPG
     
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  13. Sjm9911

    Sjm9911 Well-Known Member

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    All good ken, sometime you do stuff just to do them. Have fun with it!
     
  14. Bowman3d

    Bowman3d Well-Known Member

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    Ken I know. It was posted tongue in cheek. Hence the edit that my laughing emoji didn't work.
     

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