New tankless installed....this can't be normal.

Discussion in 'Tankless Water Heater Forum' started by jed1154, Apr 6, 2011.

  1. jed1154

    jed1154 New Member

    Messages:
    98
    Location:
    Texas
    This new unit gets MUCH hotter than the old. When its done being used, you can feel the heat emanating from it a foot away. My infrared thermometer shows the chambers at 270 degrees. How can that be good? When the water shuts off, after a few seconds, you can hear the water bubbling and gurgling in the unit...sounds aweful, and then some things click once or twice and a final pop after 30 seconds and its done.

    Is this unit faulty? Its a Supreme Tankless Heater. Also, the case of the unit that is attached directly to my wall is currently at 150 degrees. Seems aweful hot.
    Last edited: Apr 6, 2011
  2. jed1154

    jed1154 New Member

    Messages:
    98
    Location:
    Texas
    I hate to be a pest but can someone chime in on this? I can't get a hold of the manufacturer. When the unit shuts off, it boils the water and must back up into the cold side as steam or something. It did this as I was putting the cover on and I touched the damn cold water side and it literally just burned the F-ing fingerprint off my damn finger. The case gets so hot you can't hold your hand on it.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    It sort of sounds like the flow sensor is not shutting the unit off when the flow stops...
  4. jed1154

    jed1154 New Member

    Messages:
    98
    Location:
    Texas
    Yeah...something. I finally got a hold of the manufacturer and they said they had another unit come in today with the exact same problem. They have never had the problem before and suspect a batch of faulty parts....supposed to keep me posted on the fix.
  5. Dana

    Dana In the trades

    Messages:
    2,839
    Location:
    01609
    It's either defective or mis-installed. In either case, you should have a temperater/pressure valve plumbed near the output pipe (do you?) do limit the risk of a steam explosion. The temperature of the unit's case should never exceed the temp of the water flowing out of it, which should never be more than 120F to limit scald hazard.

    270F is a scary-high temp for the outside surface of the heating chambers, even if your normal water pressure is 50psi- it's definitely boiling. I'd rip the thing out of my house ASAP, even if that's how it's designed to work.
  6. jed1154

    jed1154 New Member

    Messages:
    98
    Location:
    Texas
    Its installed correctly, its hard to mess that up...one pipe in, one pipe out...three wires..red to red, black to black, and copper to green/grnd.

    None of my tankless heaters have temp/pressure relief valves installed near them. Three sets of plumbers have done work on them and no one installed or made mention of it.

    I have it turned off for now awaiting an answer from the manufacturer.

    The water temps on my bosch and seisco, both easily exceed 120 degrees and that is all electronically controlled as far as I know. Basically, if you don't want it that hot, mix it with cold water. :/


    How come I can't find information on 'good' tankless electric heaters? How come there arent any brands that seem to stick out above others? Is it because no one cares? Is it because they are all about the same?
    Last edited: Apr 7, 2011
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    Few homes are wired with enough service to make electrical tankless systems viable for many uses except for a single shower or a couple of faucets. And, except for a few locations (relatively speaking) electrically heating the water is a lot more expensive than gas. So, there's more volume in gas, more choices, and a better fall-out of poor performers.

    You'd have to read the installation manual on whether a unit requires a T&P valve; on a tank type, it is required. Most tankless will work better with a tempering valve on the output to ensure the water supplied to the house is not excessively hot. Where I live, they are required, not optional.
  8. jed1154

    jed1154 New Member

    Messages:
    98
    Location:
    Texas
    Fortunately, or unfortunately as the case may be, my home was wired to hand tankless, but they used smaller gauge and segregated teh plumbing system so has to have smaller, but more, tankless heaters. None of them have to put out more than 3gpm max. Its also handy because when one goes out in a shower, there is another shower available and means of getting hot water elsewhere. Sucks when they go out, but I dont know how long they should last. Seems like I watched my folks swap out about 3 tank style water heaters in about 30 years.
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    Depending on your water conditions and the luck of the draw, a tank type water heater can last anywhere from 5 to over 25 years, often with no maintenance in between. A tankless might last that long, but it is highly likely it won't without regular service. 3gpm is probably fine for any standard showerhead, but is really weak if you ever want to fill a tub or add a second showerhead, or even have someone using the sink while the shower is running.
  10. jed1154

    jed1154 New Member

    Messages:
    98
    Location:
    Texas
    This unit will handle up to 4gpm. We have had a shower, kitchen sink and dishwasher going at the same time with no serious issues for the shower taker. It seems to work ok.
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    It depends a lot on how cold the incoming water supply is. Depending on where in TX, it may be quite warm most of the year; this helps lots. Try that in say North Dakota where the water is just over freezing...doesn't work. Your 4gpm might end up 1gpm.
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