Any experiences with the Bosch AE 125 (Electric) Tankless?

Discussion in 'Tankless Water Heater Forum' started by STyler, Oct 2, 2009.

  1. STyler

    STyler New Member

    Messages:
    43
    Location:
    Rock Hill, SC
    Does anyone have any info regarding this unit's reliability? Are there better options for electric tankless water heaters? There's no gas available so I need to stick with electric.

    This is the only unit I could find that, at least on paper, meets my needs - from a recognizable brand name. Of course, I don't recognize the brand for their expertise in water heaters, so I'm willing to consider other brands.
    Last edited: Oct 2, 2009
  2. Dana

    Dana In the trades

    Messages:
    2,933
    Location:
    01609
    Do you have 120Amps of 240V to spare? (That's a heluva heater!)

    May I ask why tankless, (and why such a big 'un)?
  3. zl700

    zl700 DIY Senior Member

    Messages:
    237
    Location:
    Texas
    Much better electric tankless out there like the Dolphin, Seisco, and Stiebel Eltron.

    Many units like the Dolphin has some sort of pulsing control of the elements that prolong life and stage much better for varying flow changes.

    The Bosch are plastic and Ive seen and heard even more about the housing(s) failing.

    3- 40A double pole circuits is alot to give or even have available.
    Last edited: Oct 2, 2009
  4. STyler

    STyler New Member

    Messages:
    43
    Location:
    Rock Hill, SC
    Should have added the application in the original post. This is for a barn with a shower, 2 sinks, and (biggest load) a horse wash stall. Only one application at a time, but would rather over size if the unit can stage the heating - and I'd like approx. 5 gal a minute capacity if possible - for the horse stall.

    I specifically added a 200 amp service instead of 100 amp because of the requirements of this model.
  5. STyler

    STyler New Member

    Messages:
    43
    Location:
    Rock Hill, SC
    I'll check those out. I shied away from brands I hadn't heard of out of fear that they were just some fly-by-night outfit that decided to start importing appliances from China. If these companies have some history with this product, that's good enough for me. Any models specifically that are comparable in capacity - and at least close in price - or should I expect to spend more than the Bosch in order to improve the reliability?
  6. D'Brie

    D'Brie Apprentice Plumber

    Messages:
    44
    Location:
    NW Washington State
    Bosch = Boo

    The few times I have worked and helped work on Bosch tankless water heaters I have found them to be way behind the times. You may want to look into a Rinnai unit.
  7. zl700

    zl700 DIY Senior Member

    Messages:
    237
    Location:
    Texas
    What?

    D'Brie,
    Rinnai does not make an electric tankless unit
  8. bosch is junk

    you would be wise to stay away from all electric tankless heaters....

    their are stories of homes that pulled so much juice that the rest of the homes around them that were hooked up to the same transformer, all their lights dimmed when the tankless unit called for power....:D:D

    stick with a normal 50 gallon tank type heater and put a blanket on it....


  9. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    Do you have any age-at-replacement numbers for tankless heaters in the US?

    Here's what little I have for elec. water heaters with tanks.

    age at replacement|number replaced at this age
    2|1
    2|1
    7|1
    8|1
    17|1
    18|1
    36|1

    Avg = ~13 yrs
    Last edited: Oct 11, 2009
  10. D'Brie

    D'Brie Apprentice Plumber

    Messages:
    44
    Location:
    NW Washington State
    Oops, my bad, thank you I stand corrected (tail between legs):eek:
  11. STyler

    STyler New Member

    Messages:
    43
    Location:
    Rock Hill, SC
    How does a 50 Gallon tank - even with a blanket help in this situation?

    I really don't want to heat water for 20 days so that it is available on the 21st day when I need it. And I want to be able to wash more than half a horse at a time.

    If I could make a tanked heater work without being extremely wasteful because of it being used so infrequently, I'd be all for it.
  12. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    Back in the 70s I hooked up a clock through a dropping resistor to my tank elec. water heater.

    Without external insulation it was on 5 min. every 5 hrs. With external insulation, 5 min. every 7 hrs.

    Does anyone have data from someone without an ax to grind on how much heat loss there is nowadays from tanked elec. water heaters?
  13. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    5 mins every 7 hrs (0.3 days) = 45 min every X days.

    0.3/5 = X/45, X = 2.7 days, so depending on your level of insulation you can save by having it off for days at a time.

    45 min @ 4500 W @ 10 cents/kwh = 34 cents. Could I pay you 34 cents or less to wait 45 mins for hot water? If no, then leave the heater on or put it on a timer.
  14. STyler

    STyler New Member

    Messages:
    43
    Location:
    Rock Hill, SC
    I have no allegiance to tankless - in fact, I'd prefer not to use one. However, I can't find a way to get the volume of hot water I need to wash my horses without draining the tank. I have no problem disconnecting the water heater when not in use, or waiting a couple hours for an 80 gallon heater to warm up. I do have a problem if I drain the tank in the middle of washing a horse and have to wait another recovery period in order to finish.

    Still researching the possibility of simultaneous operation of the dual elements in a tank design, and trying to find out the recovery time - but there's very little info out there.
    Last edited by a moderator: Oct 30, 2009
  15. SteveW

    SteveW DIY Senior Member

    Messages:
    1,052
    Location:
    Omaha, NE
    Not that he needs my help, but will go on record in support of MP Mark. I find his take on things to be honest and to the point.

    Where else are you going to get FREE ADVICE from experienced plumbers like him? He doesn't have to spend his non-working time helping out us DIY'ers - but he does.
  16. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    A 2 GPM shower = 16# of water per minute
    Raised 50F would take 800 BTU/min = 48,000 BTU/hr = 14 kw. Most water heaters use 9 kw.

    You'd need 60 A @ 240v and this would leave the water temp in the tank the same as it was before the shower, so this is a max and it's what a tankless would draw, if I haven't made any arithmetic mistakes.

    How many gallons of how hot water do you need?

    What is the lowest incoming water temp?
    Last edited: Oct 23, 2009
  17. sorry about the bind in your shorts

    hooking two elements up to run together will require
    much more power than 220... you are getting into a commercial application type water heater...

    you cant do that without blowing the breaker, heating up the wire ect.... it wont pull enough to heat up 2 4500 watt elements ......

    ...

    if you already have a 50, go out and buy an 80, and hook them up in series...

    you will have to run another 220 line , and you
    can also just turn them off when not in use .
    Last edited by a moderator: Oct 30, 2009
  18. FloridaOrange

    FloridaOrange Plumbing Designer

    Messages:
    1,317
    Location:
    SW Florida
    Electric tankless takes a huge amount of power if you want a good amount of flow. I prefer tank type with electric.

    Since this sounds like a remote situation, have you considered a gas tankless? You could run it off of a decently sized LP tank.
  19. STyler

    STyler New Member

    Messages:
    43
    Location:
    Rock Hill, SC
    Not sure how many gallons - but it'll be far in excess of 2 GPM. I'll have a non-restricted 3/4" supply of hot and cold to the mixing valve and a virtually unrestricted sprayer. It takes about an hour per horse, and while the usage is pretty heavy, it isn't constant.

    Power isn't an issue - I have plenty available.
    Last edited: Oct 23, 2009
  20. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    First cut: 80 gals @ 160 F combined with 80 gals @ 50 F gives you 160 gals @ 105 F.
    How cold can the shower be?
    Will 160 gals wash one horse?
    Once the BTU/hr output is established there are many ways to supply this many BTUs input over hours or days preceding the shower. The heat can be stored in water or iron or whatever. You probably want to stay under 160 F for water but with iron you can pretty well heat it as hot as you need.
    Last edited: Oct 23, 2009
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