AOSmith R2VR-180E 100 Tankless fluctuating hot and cold

Discussion in 'Tankless Water Heater Forum' started by Mike Whisler, Apr 1, 2020.

  1. Mike Whisler

    Mike Whisler New Member

    Joined:
    Apr 1, 2020
    Location:
    Chehalis
    I have an electric ao Smith water heater. Unless I turn it all the way up it fluctuates between hot and cold. I don't have a manual and the system was here when I moved into my place a year ago. Is there a way to fix this or is that just how these systems are
     
  2. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    You have a tankless that is electric in Washington State? Heck, even the gas tankless will fluctuate here.

    [​IMG]

    I think the chart is for best circumstances, meaning an incoming water temperature of 70 degrees.
    Washington State is more like 50 degrees. That means the above chart is very optimistic.

    I have a gas tankless running at 199,000 BTU and I'm more like two showers at a time and five gallons a minute at 120 degrees.
    The electric tankless will do much less than that.

    [​IMG]
     
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  4. Mike Whisler

    Mike Whisler New Member

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    Chehalis
    How do I set it so it doesn't go from hot to cold while I'm taking a shower without turning it all the way up? I don't know how to adjust the settings.
     
  5. WorthFlorida

    WorthFlorida The wife is still training me.

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    Orlando, Florida
    Do you mean the tankless heater or the hot water in the shower? What is the model number of the tankless? Do you have water saver shower head?
     
  6. Mike Whisler

    Mike Whisler New Member

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    The hot water in the shower. When I turn it up it will go from warm to cold back to warm it will not stay steady unless I turn it all the way up. Then it is just hot water. Is that an adjustment I make on the tank? And no I dont have a water saver shower head. the model number is R2VR-180E 100
     
    Last edited: Apr 4, 2020
  7. Terry

    Terry Administrator Staff Member

    Joined:
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    Occupation:
    Plumber
    Location:
    Bothell, Washington
    It may be very difficult in Washington State to do tankless electric due to our cold incoming water temperature. However, with a model number we can check to see what yours is capable of.
     
    Last edited: Apr 4, 2020
  8. Mike Whisler

    Mike Whisler New Member

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    The model number on the tank is R2VR-180E 100
     
  9. Mike Whisler

    Mike Whisler New Member

    Joined:
    Apr 1, 2020
    Location:
    Chehalis
    The model number on the tank is R2VR-180E 100
     
  10. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    It's either the tankless or the shower valve cartridge.
    Is this a new problem or had it when the home was bought? Does this happen with other fixtures such as the kitchen faucet? You cannot try it with HE washing machines. If you run the shower when you have the problem, let it run and go to the tankless unit. Carefully place your hand on the hot output side pipe and see if it changes temp. If it is a steady warm or hot temperature, the shower valve cartridge could be bad. If the temp changes then it the tankless.
     
  11. Mike Whisler

    Mike Whisler New Member

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    Apr 1, 2020
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    Chehalis
    It has been doing this since I rented the unit. It is a single wide mobile home. No it does not do this for any other faucet. It just does it in the shower. I have lots bed here for almost a year and a half. It is an AO Smith tankless water heater. I also just noticed a code. It says E06. Is that an error code?
     
  12. WorthFlorida

    WorthFlorida The wife is still training me.

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    Retired
    Location:
    Orlando, Florida
    Here is the manual, Since you adjust the flow at the shower to max hot water flow to get all hot water and other faucets that use less water that do not experience the problem, I'm leaning that it the cartridge in the shower valve body. It doesn't seem to be the tankless and by increasing the temperature at the tankless probably will not fix the problem. Doing so you may burn yourself or others. Still do the hand temperature test to verify what the tankless is doing. Since you are renting, the landlord or the management company should be taking care of it.


    https://www.aosmithatlowes.com/medi...n-manual-and-use-and-care-guide-100285618.pdf
     
  13. Mike Whisler

    Mike Whisler New Member

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    Chehalis
    Thank you. I did try what you suggested and turn the water on and held the outlet tube from the tank. I could feel temperature change on the tube and I discovered that the E06 code means that the temperature is too high. It is currently set at 110 degrees ferenheit.
     
  14. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    Good find. It's not that 110 is too high, the water temperature is getting above the 110 degree setting. It reads fvthe software determined it was too high. How high is not known but probably getting too high above 120 degrees. The manual reads that the factory setting is 120 degrees but local codes and liability for the installer probably put it at 110 degrees. The tankless may have a runaway thermostat or the flow sensor is not detecting the proper water flow.

    Screen Shot 2020-04-04 at 4.58.24 PM.jpg
     

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