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cannesdo's avatar
cannesdo
Explorer
Jul 02, 2019

Can anyone recommend a tankless on demand water heater?

I'm currently on 30A and would like to fill a soaking tub with hot water if possible. It would have to be hard-wired into my breaker box. I'm wondering if that's possible with the amps I have to work with. If everything else is off in the rig is there a unit that will allow me to fill a tub in 20-25 min. for a hot soak? I'm guessing it would have to be under 20 amps. I've seen some that are 60 and one tonight that is exactly 20 amps. Wondering if anyone ever tried doing this.

Thnks much...
  • cannesdo wrote:
    dougrainer wrote:
    They do NOT make a 120 volt Tankless Water Heater for RV's. Doug


    1. My neighbor had one attached which worked great (but he used it for showering.

    2. It's not for my RV. It's for my shed.


    That's OK, But WHY post on a RV forum????????? Doug
  • We didn't have space for a Tankless Water Heater to fill our hot tub because the Baby Grand Piano was taking up all the available room.
  • generally if water tastes sweet like bottled water then it is not as hard as the stuff that makes horrible tasting coffee.there are moderate priced dip and read instruments that far more accurate. Clothes washed in our water can stand on their own after drying on a clothesline.
  • MEXICOWANDERER wrote:
    Hard Earned tip

    Use it with fairly mineral free domestic water and you will be pleased with its performance.

    Use it with hard water and get depressed

    These things deposit minerals on flow tubes like nothing I've ever seen.
    Pre-treated softened water? Great.

    I have three units that the kids used without my knowing it. Waiting for me to declog them when I get home. Hydrofluoric acid and a high Ph neutralizer


    Thanks for the tip. We have a system using treated lake water here. Would that work?
  • dougrainer wrote:
    They do NOT make a 120 volt Tankless Water Heater for RV's. Doug


    1. My neighbor had one attached which worked great (but he used it for showering.

    2. It's not for my RV. It's for my shed.
  • dougrainer wrote:
    They do NOT make a 120 volt Tankless Water Heater for RV's. Doug

    Was thinking the same thing. The only way I can think of to get instant, high volume, continuous flow, hot water in an RV, is from a propane fired device like a Truma AquaGo Comfort Plus.
  • I installed one in my s&b, will not do it again.
    You must flow water at a certain rate (on my 9200 watt model it's .9 gpm) or the unit doesn't turn on. And if the water flows too fast, it doesn't get sufficiently heated.
    For your theoretical 30 amp use, this model is an example,
    Aqua power unit
    3000 watts @ 120 VAC and will provide water at about 90-100 F from a 55 degree supply at a flow rate of .59gpm.

    Trying to fill a soaking tub will take a very long time and will cool before you can get it filled.
    PDF showing flow rate and temp rise for various models
    operating guide
  • Hard Earned tip

    Use it with fairly mineral free domestic water and you will be pleased with its performance.

    Use it with hard water and get depressed

    These things deposit minerals on flow tubes like nothing I've ever seen.
    Pre-treated softened water? Great.

    I have three units that the kids used without my knowing it. Waiting for me to declog them when I get home. Hydrofluoric acid and a high Ph neutralizer

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