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LP lines on house Freezing

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  • LP lines on house Freezing

    Does anyone have any thoughts on the LP lines on my house freezing?

    History:
    I use very little LP, its just for the range top I have a convection over gas stove. This summer I got into an argument with the gas company that had been supplying my tanks.I use less than 100# a year, they wanted to charge me $700 a year whether or not I used the gas
    I gave them back their tanks and installed 2 new 40# tanks and set the house up with a new regulator from the trailer and RV store, all has been fine till know. Last week my wife told me that we were out of gas so when I got home I swapped them over, still no gas. I used a hairdryer on the lines and regulator and viola we had gas again. I have now been going through this every day.

    Here is what I'm thinking so far:
    1- An LP setup is a pressurized,closed system there should be no way for moisture to get in.
    2- The only way for moisture to keep re-appearing is the tanks were not purged properly on the initial fill there still being air in them causing moisture at dew point hence the daily freezing.

    Anyone ever had this problem or thoughts on it?
    Bill


    "I'm not young enough to know everything"

    My Project
    1973 21' Cruiser Restore

    The Resurrection of the SeaGem

    The Hijack Zone - Zombies Welcome


  • #2
    Re: LP lines on house Freezing

    I had that problem on my garage heater. When the temps get real cold the LP tank would freeze at the fittings...

    Looking forward to the answers you get here..I never figured out why they freeze.I tried 3 different tanks.
    sigpic

    1981 ChrisCraft 210 Scorpion K,175 Johnson SeaHorse

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    • #3
      Re: LP lines on house Freezing

      As was sayed if your propane isnt purged well enough you tend to get a air lock, I dont know why, but I flipped the tank up side down turned the valve, and depressed the ball lock mech, blasted out a second or two of propane, never had another problem, as for freezing up I dont think you have any problems till it hits -30/-40c (-40f is the same as -40c) at least thats about were it use to always plague us starting our trucks. As for the ice build up on the fittings thats the condinsation attaching and iceing it self to the fittings as the gas is already below zero.
      rob
      Last edited by rbh; December 21st, 2009, 12:25 PM. Reason: add
      home is where we drop anchor

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      • #4
        Re: LP lines on house Freezing

        Originally posted by rbh View Post
        As was sayed if your propane isnt purged well enough you tend to get a air lock, I dont know why, but I flipped the tank up side down turned the valve, and depressed the ball lock mech, blasted out a second or two of propane, never had another problem, as for freezing up I dont think you have any problems till it hits -30/-40c (-40f is the same as -40c) at least thats about were it use to always plague us starting our trucks. As for the ice build up on the fittings thats the condinsation attaching and iceing it self to the fittings as the gas is already below zero.
        rob
        Thanks RBH for your input, wow -40c I don't think its been that cold here since the ice age.
        Flipping the tank over is a good idea, I'll try that. When you flip the tank over I imagine is the same as in refrigeration, your pushing liquid at that point which would push out any impurities.

        I'm having the freezing problem from about 29f/-1.5c I figure it must be a freezing problem because the hair drier on the lines seem to do the trick. I initially figured doing it once would cure the problem by pushing whatever water was in it out but it is now an everyday problem
        Bill


        "I'm not young enough to know everything"

        My Project
        1973 21' Cruiser Restore

        The Resurrection of the SeaGem

        The Hijack Zone - Zombies Welcome

        Comment



        • #5
          Re: LP lines on house Freezing

          A simple heat tape from the hardware store, or a modified crankcase heater mignt do the trick, never dealt with that problem before.
          '90 Chaparral 2000SL
          5.8 Cobra
          '67 MFG Westfield Regal
          80hp V-4
          (No private messages)

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          • #6
            Re: LP lines on house Freezing

            I am thinking that if the tank was not purged correctly that could be a problem, as well if the lines got any condinsation in them between replacing the rental tank, they could freeze up, once you have the propane running freely, keep appliance on for a while and see if it starts to slow, just to be sure.
            home is where we drop anchor

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            • #7
              Re: LP lines on house Freezing

              It is a flow problem it is the same thing as cracking the valve will put a frost line on the tank from the pressure difference. You may be asking for more than the smaller tank has to give. I have the same problem with 20lb tanks on my salamander.
              sigpic

              90 supra bravura pmc351 1.23/1 pmc40
              96 seaswirl squirt 115omc turbojet
              88 kawasaki sj550
              88 kawasaki x2 650
              92 yamaha waverunner III
              94 seadoo xp

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              • #8
                Re: LP lines on house Freezing

                RBH - I tried running the stove after heating up the lines, it works fine for a day. By the next morning its frozen again.

                86 century -, I think your on to something there with it being a flow problem. I actually just go off the phone with one of my customers who's head of technical services for gas boiler manufacturer. He said the same thing basically, he said it is most likely a combination of the tank surface area at the top and the gas regulator valve. The gas regulator might be to small and that on a call for gas the velocity is to great causing it to push liquid instead of gas which is then freezing in the lines.

                a70eliminator - I'm thinking you might have the simplest solution but is heat trace ok on a gas line
                Last edited by HVAC Cruiser; December 21st, 2009, 06:28 PM. Reason: grammar
                Bill


                "I'm not young enough to know everything"

                My Project
                1973 21' Cruiser Restore

                The Resurrection of the SeaGem

                The Hijack Zone - Zombies Welcome

                Comment



                • #9
                  Re: LP lines on house Freezing

                  Mine will do the same thing if it is 75deg in the garage(the tank is inside)so i dought the heat tape would work but.
                  sigpic

                  90 supra bravura pmc351 1.23/1 pmc40
                  96 seaswirl squirt 115omc turbojet
                  88 kawasaki sj550
                  88 kawasaki x2 650
                  92 yamaha waverunner III
                  94 seadoo xp

                  Comment



                  • #10
                    Re: LP lines on house Freezing

                    Originally posted by rbh View Post
                    As was sayed if your propane isnt purged well enough you tend to get a air lock, I dont know why, but I flipped the tank up side down turned the valve, and depressed the ball lock mech, blasted out a second or two of propane, never had another problem, as for freezing up I dont think you have any problems till it hits -30/-40c (-40f is the same as -40c) at least thats about were it use to always plague us starting our trucks. As for the ice build up on the fittings thats the condinsation attaching and iceing it self to the fittings as the gas is already below zero.
                    rob
                    I agree with RBH, airlock...anytime I've had that problem with the grill, I pull the line and drain some LP. It's always fixed it.

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                    • #11
                      Re: LP lines on house Freezing

                      how was it concluded that the line is freezing?

                      sounds like you just aren't getting fuel through the line.
                      Baba-buoy.

                      Comment



                      • #12
                        Re: LP lines on house Freezing

                        Originally posted by Howard Sterndrive View Post
                        how was it concluded that the line is freezing?

                        sounds like you just aren't getting fuel through the line.
                        it worked fine up till now all spring and summer etc, only started acting up in the colder weather. At first I thought the tank was just empty but when I checked it it still had 30# in it I have 2 40# tanks. On a hunch I hit the lines with a hair drier and in about 10 seconds of heat the gas started flowing again to the stove. I have had to heat the lines every day since Friday with the exception of today, I'm assuming that's because its 35 out today.
                        Bill


                        "I'm not young enough to know everything"

                        My Project
                        1973 21' Cruiser Restore

                        The Resurrection of the SeaGem

                        The Hijack Zone - Zombies Welcome

                        Comment



                        • #13
                          Re: LP lines on house Freezing

                          1. You don't want a heat tape anywhere near propane, unless yer into bomb making.

                          2. Propane will hit zero pressure at about -20 degrees F. The pressure you need is 11 inches water column, which is just a bit over 1/2 psi. If you disconnect the tank and crack the valve, you'll have plenty of pressure.

                          3. A cheap single stage regulator will sometimes act up when it gets cold. Moisture on and in the regulator can agravate the problem. Warming it up will help for a time.

                          4. Moisture in the tank, either from a supplier with wet gas, or from before the original fill can cause these kinds of problems. They pump liquid fuel from the bottom of the tank, and water is about twice as heavy as liquified propane.

                          I suspect a fresh regulator, and a simple structure to keep rain and snow from getting on the regulator will fix the problem.

                          hope it helps
                          John

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                          • #14
                            Re: LP lines on house Freezing

                            You have two things working against you.
                            The cylinders are supplying gas (not liquid), and the vapour pressure of propane at say 20 deg F is 1/4 what it is at 80 deg F. That is what "drives" your gas delivery at the stove and at this time of year can be as little as 1/4 of summertime "power".
                            The other constraint is obviously the length and size of supply piping.
                            Too long a run, and/or too small a diameter, and you have line-losses that coupled with the reduced operating pressure take the available flow below what will feed the stove.

                            It is possible that the lines are actually freezing, but that can only be from moisture...and most likely that would be an incomplete purge prior to filling the tanks initially.
                            To separate the two causes, next time you :"freeze up", get a tub larger than the in-service 40#er, and put the tank in it. Then fill the tub with warm water (75-90 deg F) to about 2/3 the cylinder height . If that solves the problem and gas flows, you have a system problem...as described at the top. You need bigger lines or bigger tanks....or both. Since presumably you are using the same lines as previously it would make sense that you need bigger tanks.

                            If the hot water does not have an impact, and if the hair dryer is used at the same constriction point each time and then results in continuous flow for a while, it may well be moisture in the system.

                            In either case the root change has been new tanks. IMO that is where to start....if the hot water does not work, take one of the tanks and have it "really" purged and then filled, and try that.
                            You do not need a parachute to skydive. You only need a parachute to skydive twice.

                            I don't belong to an organized political party. I'm a Democrat. (Will Rogers)

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                            • #15
                              Re: LP lines on house Freezing

                              Originally posted by j_martin View Post
                              1. You don't want a heat tape anywhere near propane, unless yer into bomb making.

                              A check with any gas utility and/or competent gas fitter/contractor will prove that statement baseless.
                              As with any gas-related installation, it is critical to use the right equipment and the correct procedure, but this is a routine and safe design element in many service installations.

                              On the other hand, there should be no reason that heat-tracing these lines should be suddenly required, especially in the temperatures the OP reported.
                              You do not need a parachute to skydive. You only need a parachute to skydive twice.

                              I don't belong to an organized political party. I'm a Democrat. (Will Rogers)

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