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Bock indirect water heater

Running out of hot water quickly


  • SuperTech
    SuperTech Member Posts: 1,943
    > @plumbcrazy said:
    > Running out of hot water quickly

    Let's start with a picture and a story about what's happening. Details are really helpful.
  • plumbcrazy
    plumbcrazy Member Posts: 4
    Sorry..new here..zone for indirect working fine..aquastadt seems to be working..pressure is good on hot water at fixtures..was wondering if its a possibility coil has build up on the outside and is not transferring correctly
  • plumbcrazy
    plumbcrazy Member Posts: 4
    Don't have picture..installed approx.10 years ago..customer says family getting 2 quick showers and out of hot water and takes a long time to recoup
  • hot_rod
    hot_rod Member Posts: 19,942
    Look at the dip tube also. Those tanks have massive, smooth enameled coils, rare to see them scale up enough to drop performance.

    Take a 5 gallon bucket, runtime tank up to temperature and clock exactly what come out.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • GBart
    GBart Member Posts: 746
    You really need a pro to check it out, there might be nothing wrong with the unit it could be your house, it could be if you have water treatment a soda ash deposit ruined it, it could be your washing machine is allowing cold water into the hot line, could be you have anti sweat valves for your toilets doing the same.
  • clammy
    clammy Member Posts: 2,983
    I think I would chk the dip tube if it’s good ,I would shut off boiler then run hot water till cool turn your boiler on and chk the temperature difference between inlet and outlet of the tank also listen and you might hear a slight Kettling or popping noise . If your temp difference is 10 degrees or less I would think your tank coils are lined up .i have a bock and recently had issues w low delta t across tank and slight what I would call kettling sound . I rigged up a pump drained her 1/2 way and added about 2 gallons of CLR could not get redlye outta stock .pumped from bottom of the tank to top for a few hrs and then drained and flushed numerous time and ran the tank through bout 1 hr to remove residue out took a long time but it did increase my delta n removed most of the lime and scale build up .would I do this for a customer I think not , by the time you where done t and m it would be a big bill . I think I spent bout 5 or more hrs .i use to use a lot of the st tank a few had the same issue tube failure in tank and some had failed thermoglazing on interior of the heating side .as for performance I found the bock was about the same as for from a cold start n recovering as my buderus downfall is there a pia to clean .unfortunltly I find it difficult to find smaller tanks w either side or top manholes that are decent sized. To myself that’s the down fall of most indirects .yes u could use a big V but on small jobs w only 1 1/2 bath and small boilers I can’t warrant it .The water quality in my parts gets worse as years go by I love using indirects but w the hard water and ho really not concerned about water softening or conditioning might as well use a standard gas hot water heater direct vent if need be and toss it every 7to 10 years or till see leaks much cheaper n everybody loves cheaper ? I started using turbo max tanks recovery is great n I feel those coils are easier to de lime and flush clean as compared to a standard indirect less volume to flush .the hinge pin on the turbomax is boiler piping use of a pump and bpm through the tank also but a huge fan or the temp control I usually upgrade to a ranco etc . Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • SuperTech
    SuperTech Member Posts: 1,943
    The process clammy mentioned is what I try for scaled up coils, but I can't say I have ever run into any issues with a Bock.
    If it is scale buildup I would definitely install a AP401 scale stopper cartridge after flushing the coils.
  • pecmsg
    pecmsg Member Posts: 4,199
    Drain the water heater
    Cold Start how long does it take to reach temperature?
    Whats the delta of the Boiler Water In and Out?

    As stated Measure with a 5 gal bucket how long before running out of HOT water?

    Get back to us
  • plumbcrazy
    plumbcrazy Member Posts: 4
    Drained water heater..Removed aquastadt..eyed up coil and dip tube..all good..filled back up..ran boiler..zone valve opened..pump turned on..got indirect up to temp..ran hot water at fixtures..did it a few times and noticed when the indirect called pump would not always turn on..replaced aquastadt relay..all good..just surprised no complaints about the heat since there's one main pump..Thank you all for your comments..extremely helpful..Thanks
  • flat_twin
    flat_twin Member Posts: 341
    Thanks for posting your findings.