Preventing freezing of the fresh water tank.

Discussion in 'General RVing' started by kegman, Dec 4, 2003.

  1. kegman

    kegman New Member

    What is the best method for keeping the fresh water tank from freezing while dry camping. My trailer has small 12vdc heating pads attached to the gray and black water tanks to help them drain. Can these 12v pads be used for the fresh water tank or do they use too much battery power to be practical. Can the pink RV antifreeze be mixed with the fresh water to be used for everything but drinking? My tank is totally exposed under the rig and the pump supply line comes out of the bottom of the tank making a natural water trap in the hose. Any suggestions?
     
  2. BarneyS

    BarneyS Senior Member

    Preventing freezing of the fresh water tank.

    I would suspect they use quite a bit of power and would drain you battery quite rapidly. I imagine they would work if you had a generator to keep the battery charged. If that is not possible, I think I would use portable water jugs instead of the tank. I cannot think of any practical way of keeping those tanks warm without using electricity. You certainly cannot put anything with a flame under there! :eek:
    Good luck.
     
  3. Flyboy

    Flyboy New Member

    Preventing freezing of the fresh water tank.

    Kegman,
    We had a similar problem way back when with a small travel trailer. We did a lot of dry camping...still do, and the unprotected tanks are a problem. Our fix was a three step process. Step 1: Installed an inside/outside digital thermometer with the outside probe glued to the fresh water tank. This gave me the ability to monitor the water temp at a glance from inside the trailer. Step 2: We purchased 1"x4'x8' sheets of foil faced foam insulation and construction adhesive from Home Depot. The adhesive must be a type that is compatible with the plastic tank and the foam backing. We then cut and fit and glued until the tank was covered. All seams were sealed with aluminum tape. Step 3: The last part was tying into a hot water line, installing a small brass valve (easy to control flow volume) in a convenient location and then tying that back to the fresh water tank. Our tank had an extra outlet that was not being used. Had it not had that, I was prepared to drill and install a 1/4" fitting into the tank. I was then able to open the small brass valve which allowed a metered amount of hot water to return to the fresh water tank. All I was concerned about was keeping the temp above 32 degrees...not actually warming up the water. After several uses I was able to determine how many turns of the valve, based on outside temperature, would keep out fresh water from freezing. Final notes: Our water heater actually used very little LP and this additional load was barely detectable. We had also previously installed a 2 gallon accumulator tank which allows approximately 2 gallons of water flow before the 12volt pump turns on. This kept the pump from constantly turning on and off. I recommend an accumulator tank! (We're installing one in the DP we recently purchased). It we were expecting a 20 degree night, the water flow was about 6-7 gallons per hour (so the pump only ran about 3 times per hour @ just a little under a minute each time. No water is wasted because it never leaves your fresh water system, very little electrical usage and not much additional LP.... nothing is free!

    Hope this gives you another idea to ponder! Good luck.
     
  4. Flyboy

    Flyboy New Member

    Preventing freezing of the fresh water tank.

    Kegman,
    One final thought! If you are using an accumulator tank you could tie the hot water supply into the line between the tank and the pump. It would back flow 1-2 gallons of warm water into the fresh water tank before the pump would turn on. The pump would recharge the accumulator tank and the cycle would start over.
     
  5. Jellyfish

    Jellyfish New Member

    Preventing freezing of the fresh water tank.

    That was brilliant! Thanks. What do you fly?
     

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