Electric H/W heater ???

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Bigbobdallas, Aug 12, 2006.

  1. Bigbobdallas

    Bigbobdallas New Member

    Messages:
    42
    I change over to a electric H/Water Heater. Sear brand it says that the heating element came preset from the factor to 3800 I think was the number and it says change the setting to 5500 or what ever the number was which is the best got a 50 gal I have it set to the 5500 and it got hot real fast just dont want to scald the grandson or something like that
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    You cannot aribtrarily change the wattage of your heating elements. The thermostats, and the house wiring and circuit breaker have to be examined to see if they support a higher wattage.

    The extra wattage would heat water faster, but the thermostats determine how hot they heat it/

    You should not mess around with this. If something is not right, get a plumber in. He will know what to do.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,797
    Location:
    Cave Creek, Arizona
    3800

    Some heaters come with 3800 watt elements and are advertised as "energy saving". They use less energy per hour to heat the water but have to operate longer to get the same temperature as a 4500 or 5500 watt heater. You can only change the wattage by buying a different heater or replacing the elements, and in the case of the 5500 watt heater, possibly changing the wiring also.
  4. Bigbobdallas

    Bigbobdallas New Member

    Messages:
    42
    Water heater

    It came with instruction and it was easy to change over just disconnect a wire and move it to no. 2 and then tighten it up it was really that easy was just curious if this is better to get hotter faster. Thanks for the responce.
  5. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

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    Location:
    Columbus, OH
    You're at risk of starting a fire if your HOUSE wiring is not that correct size. You're drawing almost 50% MORE current by wiring it for 5500Watts. I would disconnect this immediately and have an electrician take a look at it to see if you can safely pull that many amps.

    Jason
  6. Bob NH

    Bob NH In the Trades

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    3,317
    Location:
    New Hampshire
    The reason they have 3800 watt elements is so that it can be run on a 20 Amp circuit.

    The NEC says that the overcurrent protection must be 125% of a continuous load. That translates into the requirement that continuous loads can operate at only 80% of the circuit rating.

    A residential-size water heater is considered a continuous load and can only be operated (per code) at 80% of the current limit of the circuit. Since a 3800 Watt element pulls 16 Amps at 240 Volts, that is how they got to 3800.

    A 30 Amp circuit can handle a 5500 watts+ heater under the same rule.

    A 4500 Watt heater actually draws less than 20 Amps but is restricted by the NEC so you need to install a 30 Amp/#10 wire circuit.
  7. vaplumber

    vaplumber Guest

    Sears actually had at one time (or reckon they still have from reading this) a dual watt element. It was actually two elements in one unit, with 3 screw terminals. A common nuetral terminal (only reffering to it as neutral. 220v has no true nuetral) shared by both coils, and a hot terminal for the low watt side plus a hot terminal for the high watt side. The "hot" wire is connected to one screw for the low watt side, and you remove it from that screw, and connect it to the other terminal for higer wattage. The down side with these in the old days was that a standard element from a hardware store will not fit as a replacement, and the sears stores around here didnt stock them, so when you needed a replacement element, you had to order it from sears, pay about $40 by the time shipping was added, and wait several days for it to arrive. Leave it on the low watt setting. Your wiring was designed to support whatever was originally put in there, and you will be heating your wiring up along with your water if you set it to 5500.
    Last edited by a moderator: Aug 14, 2006
  8. No gain in heating fast.

    no advantage to heating anything up real fast.

    Except for the one advantage of less time to get to maximum temperature.

    All disadvantages. More energy, less efficiency. Shorter time until heater blows, although still years away. More current drawn through your wires, which may or may not have been installed in the right size to handle the greater current.

    Maximum temperature is still the same -- scalding is possible in both cases depending on your turning the hot and cold faucets appropriately.

    Hope this helps.

    david
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,126
    Location:
    New England
    More wattage, quicker recovery...energy to heat what is there, the same. Only danger (and it could be big) is if the wiring and control circuit is not up to snuff to handle the larger wattage.
  10. vaplumber

    vaplumber Guest

    Check your circuit breaker. If you have a 30 amp breaker that was original in the house, probably nothing to worry about. If you have a 20 amp breaker, put the water heater back to the low wattage setting. Otherwise, the wires in the house will heat up, and you could eventually end up with a fire. The high wattage will use more electricity, costing you more, but it will heat the water up faster. The low wattage setting will give you the same water temp, but it will take a little longer to get hot after using up the hot water. You will save energy and money on the low wattage setting, and your heating element will last a lot longer. The thermostat in the water heater controls the actual water temp, so with either setting, your hot water will be the same temp. The high setting will just heat it to that temp a little faster, and will waste more electricity doing it.
  11. vaplumber

    vaplumber Guest

    I should mention my past experience with the sears dual wattage water heater. With any conventional water heater, if your hot water goes out, you can walk into any hardware store and buy a replacement heating element for less than $15, and have hot water again within about an hour. With the old sears dual watt heaters, we always had to order the heating element, and with shipping, it usually cost around $40, and you have to wait anywhere from 3-4 days to a week for the part to arrive. I had thought that sears had stopped making these units, but from this posting, I see that they are still available. If it were me, I would go ahead and order an extra heating element, and keep it handy, as the ones that you would buy from the hardware stores will not fit. These heaters were built to sears specifications, and parts are very seldom available locally. Just a friendly suggestion for future reference.
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,126
    Location:
    New England
    There should be no reason for the higher wattage element to use more electricity...it will run for a shorter amount of time, but in the end, not cost more since it DOES run for a shorter amount of time. This assumes your thermostat is set the same, regardless of the element used. For ease of the math, say it takes a 1KW element an hour to heat the water, you've used 1KWH of energy. If the element was a 2KW device, it would take 1/2 hour to do the same thing. 2 * 1/2 = 1KWH. So, if the wiring can handle it safely, the larger wattage element would recover faster. There would be no reason for it to get the water hotter. If the element was limed over, you might get more popping and noises with the higher wattage, but then you probably need to replace it anyways.
  13. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    Theoretically that makes 110% perfect sense. ACTUALLY, I bet they're not equal. I don't know why off hand, but I wouldn't be surprised if there weren't the same. If it was gas, I would think maybe the water couldn't absorb the heat as fast w/ high heat and up the flue it would go, but elec isn't vented. Well, maybe w/ higher elec BTU you'd absorb more heat into the jacket of waterheater? Something...I dunno, speculating here. Work w/ me...

    Jason
  14. vaplumber

    vaplumber Guest

    Makes good sense in print, but in reality, this is far from true. You have to apply basic physics here. Double the wattage does double the heat output, but it does not cut the heating time in half. A great example is that new high efficency furnace in your basement. Physics is what makes this work. When you fire it up in a cold house, it may put out 100,000 BTU, then switch to 50,000 BTU to maintain the temp. Without physics, it would run twice as long to maintain set temp at half power, still burning the same amount of fuel. Youve got to figure in a 12-15 % effeciency loss, so if it takes that water heater 1 hour to heat 50 gallons of water to the set point, double the wattage, and it will take about 40 minutes to reach the set point. At the higher wattage, it will heat the water noticeably quicker for the initial draw, but as the temp rises, youre losing a lot of efeciency. If you read the owners manual, it should tell you how much energy you'll save at the lower setting.
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