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Hot Water Heater Temp?

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taylorgeo
taylorgeo Member Posts: 74
We installed a new hot water heater a couple of months ago, and the water gets super hot before we even get to the halfway position on the sink and tub levers.

Do you think the temp is set too high, or just not used to a new, properly fuctioning hot water heater?


Comments

  • Dave Carpentier
    Dave Carpentier Member Posts: 604
    edited April 2022
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    If you have a cooking thermometer, run hot for a while into a coffee mug in the sink and check the temperature. Really hot water is definitely a risk for scalding, you can burn before your brain says "hey, move out of there"
    Adding:
    120f = 2nd/3rd degree burns in 5 minutes
    140f = 2nd/3rd degree burns in 5 seconds
    160f = 2nd/3rd degree burns in 0.5 seconds

    We keep ours 140-145 at the tank.
    30+ yrs in telecom outside plant.
    Currently in building maintenance.
  • Ironman
    Ironman Member Posts: 7,388
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    I’d say you need to dial it down some. Or else put a mixing valve on the tank.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Jamie Hall
    Jamie Hall Member Posts: 23,567
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    I'd go the mixing valve route, @Ironman -- less bacteria, more hot water.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    GGrossIronmanpecmsgRich_49
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,767
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    120 at the faucet is what you're looking for with or without a mixing valve.

    Try setting the tank to "hot" not "B" as @Ironman suggested
  • hot_rod
    hot_rod Member Posts: 22,396
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    Two schools of thought on WH temperature, set it around 120F and it is safe for use at the faucets. Elevating it to 140F gives you legionella protection potential, and turns that 50 gallon tank in to an 80 gallon drawdown capacity if you add a mixing valve and set it at 120F.

    Know that the elevated temperature operating option will shorten the life a bit and cause more mineral precipitation if you have hard water. You may notice that on glasses when they come out of the dishwasher or glass shower doors, more spotting and white deposits.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    MikeAmann
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,364
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    Hi, Water heater controls are not precise at all, but you should have roughly ten degrees F between calibration marks. What temperature you want at the tap is affected by who's using hot water. If you just have healthy adults, you may want 130 because that's hot enough to greatly slow down Legionella and get away from before being scalded. If you have any old, young, or immune compromised people, 120 or even less is appropriate. In that case, I would keep the tank hotter and use a mixing valve, so you're not being too hospitable to the bugs.

    Yours, Larry
  • Chris_L
    Chris_L Member Posts: 336
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    Yes, it is set too high.
    I've got that same valve on the water heater for a rental unit. It is set between "Low" and "Hot." (Closer to "Hot.") I am sure I would hear about it if it wasn't hot enough.
  • taylorgeo
    taylorgeo Member Posts: 74
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    I finally checked the temperature utilizing the coffee mug/food thermometer method.

    I am at 157 degrees at the kitchen faucet. Do I simply turn that black knob to lower it?
    Dave Carpentier
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,364
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    Hi, try turning it down about three marks on the controller and see what temperature you get then 😉
    Yours, Larry
  • PC7060
    PC7060 Member Posts: 1,211
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    Chris_L said:
    Yes, it is set too high. I've got that same valve on the water heater for a rental unit. It is set between "Low" and "Hot." (Closer to "Hot.") I am sure I would hear about it if it wasn't hot enough.
    What Chris said, mine is set at 3/4 of range from low to hot.