Forum Discussion

mchero's avatar
mchero
Explorer
Apr 30, 2019

Hot water at the vanity sink

Have a hot water issue at the vanity sink. When i turn on the hot water it takes a good 45 seconds to a minute of running water before it gets hot.

This is a real issue when boondocking off grid. Don't want to waste precious water waiting for hot water.

I was thinking of installing a 12vdc circulation pump between the hot and cold lines just below the faucet. When I want hot water i would turn on the pump till the water gets hot.

I see many 12vdc pumps but need a pump that's water tight when the pump is NOT running. I don't think a centrifugal pump will do.

Ideas, suggestions??

6 Replies

  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    May 02, 2019
    I just did this in a stick & brick. 40 some odd seconds, and the water flows into a rooftop "tinaca" rotoplas 1.000 lt. tank. Somewhat different but better than wasting water.
  • mchero's avatar
    mchero
    Explorer
    May 02, 2019
    myredracer wrote:
    Make sure a 12 volt pump is rated for hot water use. If you were able to get to the piping, pipe insulation would help somewhat.

    45-60 seconds is pitiful. Ours takes maybe 15 seconds or so. Could the hot water be mixing with cold somewhere? I think I read about someone having that problem with their kitchen faucet but can't remember what the cause was.


    At the very top of my list. Hot water is a good hint.
    I have the Atwood g16ext that gets water hotter than a cherynobyl reactor core if the mixing valve sticks.

    The vanity is at the center of the full wall slide on the drivers side. The hot water heater is located right rear, a rather long run.
  • myredracer's avatar
    myredracer
    Explorer II
    Apr 30, 2019
    Make sure a 12 volt pump is rated for hot water use. If you were able to get to the piping, pipe insulation would help somewhat.

    45-60 seconds is pitiful. Ours takes maybe 15 seconds or so. Could the hot water be mixing with cold somewhere? I think I read about someone having that problem with their kitchen faucet but can't remember what the cause was.
  • Lynnmor's avatar
    Lynnmor
    Explorer
    Apr 30, 2019
    I installed a tee under the sink and ran a hose to the vent line of the fresh water tank. In that hose, I installed both a quarter turn valve and a multiple turn metering valve. The metering valve is used to throttle the flow so it doesn't spill out the vent. When the water pump cycles the second time the hot water is ready for use.
  • time2roll's avatar
    time2roll
    Nomad
    Apr 30, 2019
    I have a circulating pump to move the hot water. Used a Grundfos isolation valve between hot and cold. I did this for freeze protection but it works for instant hot water too.

    Another alternative is to add a valve to dump hot water back into the fresh water holding tank. This could use the existing pump.
  • Earl_E's avatar
    Earl_E
    Explorer
    Apr 30, 2019
    Probably not the answer you're looking for but we have the same problem and when dry camping just use the kitchen sink for hot water. It only takes a second or two to get hot.

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