Results 1 to 12 of 12
  1. #1
    Join Date
    Oct 2006
    Posts
    5

    I have a 4 family home with an ancient oil boiler that's been services well and has new devices (gauges, safety equipment, etc.).

    The external tankless coil hot water heater (with aquastat) doesn't seem to be doing the trick any longer.

    That is, after a few minutes of running the hot water, the water turns cold. But, the cold doesn't seem to bring the boiler's water temperature down to trigger the aquastat to turn on the boiler.

    I know there are more efficient ways, but I'd like to get this working without much change for the time being.

    Is it possible that there's too much corrosion inside the external coil? Possible to use a chemical to clean it? Any other possible solution?

    Thanks very much,

    Joseph

  2. #2
    Join Date
    Sep 2006
    Posts
    43
    Most companies stop using acid type cleaners long ago. More commom is ultra sonic coil cleaning. Not many people do it but try your phone book.

  3. #3
    Join Date
    Oct 2006
    Posts
    5

    Is there something I can use myself?

    Does it sound like a cleaning will do the trick?

  4. #4
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,743
    Originally posted by josephny

    Is there something I can use myself?

    Does it sound like a cleaning will do the trick?
    cleaning it may do the trick, or eat thru what little bit of metal is left of it.

  5. #5
    Join Date
    May 2006
    Location
    Philadelphia, PA
    Posts
    1,391
    60 years old? You are wasting your money trying to fix the water side of this unit. If the control is bad or possibly a wiring problem it may be worth repairing. As was mentioned if this unit is fouled to the point of not working there is probably not enough metal to clean.

    Replace it with a properly sized indirect water heater and save yourself headaches and phone calls from unhappy tenants.
    Climate Control Solutions for your Home or Office

    Serving Northeast Philadelphia and Surrounding Areas

  6. #6
    Join Date
    Oct 2006
    Posts
    5

    Can you explain where the metal is thinned by corrosion?

    Is is the exterior of the box or the internal coil or fins that might be on the interior coil?

    Thanks!

  7. #7
    Join Date
    Feb 2003
    Posts
    1,996
    The coil will thin from years of water flow and the stress /shock of cold water hitting the hot coil.

    Just get an electric HW tank if you don't want to spring for the money. Stupid waste of time and money trying to fix this.

    Maybe put an indirect tank in now, replace the boiler when you can. 60 years, you're pushing it. You know it will die in the middle of winter when you'll pay top dollar for whatever new boiler a contractor has laying around.

  8. #8
    Join Date
    Oct 2006
    Posts
    5

    Got it -- the coil appears to be as old as the boiler (thereabouts).

    My understanding is that an electric hot water heater can't make enough hot water fast enough for 4 apts and will cost a tremendous amount in energy costs.

    Putting in a gas heater means filing plans with the city and running a new gas line (many, many thousands of dollars).

    Oil hot water heaters appear to be frowned upon because of their short life.

    I'm really just trying to make it to next summer. I can then do a proper replacement.

    ugh.

  9. #9
    Join Date
    Feb 2003
    Posts
    1,996
    Getting an indirect HW tank fed off the boiler wouldn't be wasted money. You'd probably get one hext year anyway with the new boiler. There are glass lined indirects that cost less then the stainless steel ones,but you might only get 15 years out of one. (20y if you're on softer city water)

    Probably need at least an 80 gal tank. Other option is a reverse indirect. Smaller but produces a ton of hot water with a bigger boiler. Similar to your external coil.

    checkout
    http://www.thermo2000.com
    http://www.ergomax.com

  10. #10
    Join Date
    Oct 2006
    Posts
    5

    The hpproducts items look very nice.

    I'm confused about sizing though.

    Are they an "on-demand" device or a storage device or a hybrid?

    I see figures like 160 to 300 gallons available during the first hour. After the first hour, something like 100-200 gallons/hr. Seems like plenty of water.

    4 showers, 4 bath sinks, 4 kitchen sinks (no dishwashers), about 11 people (no kids) using the system.

    I assume that the larger the tank, the less frequently the boiler has to fire (a good thing). Correct?

    The Superstor Contender SSC-50 looks interesting (~$800 online plus shipping). Don't know if I'll need an expansion tank and/or circulating pump and/or mixing valve, or how much my plumber will charge to install.

    Thanks!

  11. #11
    Join Date
    May 2006
    Location
    Philadelphia, PA
    Posts
    1,391
    Call your plumber and have him evaluate the current system and your domestic HW needs. Then he can suggest the correct capacity Indirect Water Heater and controls for your system.
    Climate Control Solutions for your Home or Office

    Serving Northeast Philadelphia and Surrounding Areas

  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,074
    Don't waste your money trying to cook out that 60 year old coil, you'll just eat through it and have no hot water.

    You can replace your side arm heater with a new one, YES, they still make them.

    We take care of apartment buildings with 11 apartments on one side arm heater.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

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