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Why Do Steam Coils Freeze?

HeatingHelp Administrator Posts: 651
edited August 2016 in THE MAIN WALL
Why Do Steam Coils Freeze?

Read the full story here


  • Skepticelt
    Skepticelt Member Posts: 8
    Well written and thought out article. Thanks for sharing.
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,553
    Thanks for reading!
    Retired and loving it.
  • Henry
    Henry Member Posts: 998
    I have seen too many plumbers replace a steam trap by pipe size and not aplication. They have no idea what size orifice is in the trap.
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    Traps are dumb, think of them like meatloaf. I love it, this is why Dan's articles are always informative AND make me hungry. Every time!
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,553
    Ha! Thanks.
    Retired and loving it.
  • Grallert
    Grallert Member Posts: 667
    This is a most helpful read. Too bad I didn't read it years ago or perhaps I for got that I read it. This describes my scenario to a T. Only here the unit heater split. I will keep this in mind.
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • klong
    klong Member Posts: 4
    Excellent Synopsis... Thanks for sharing. So many parts of this ring true right now!
    EBEBRATT-Ed Member Posts: 15,767
    All good tips. It's a good idea to lower the condensate trap as low as possible. No one says it has to be right at the coil but that's where they are installed. Also a vacuum breaker or check valve as mentioned. An extra trap on the coil inlet after the control valve sometimes helps. And watch out for return line back pressure as was mentioned.
  • clammy
    clammy Member Posts: 3,113
    And last but not last use the proper type coil , a tube in tube or a non freeze type of coil is really what should be used for proper operation nothing less . You see to many guys just using any type of coil and wonder why they fail or fail to operate properly In all my years I think I be replaced a total of 3 tube in tube coils all where well over 50 years old at the youngest . All the other devices and proper piping should not be a issue If the gentle men replacing it are aware of what there looking at , usually not always the case unfortunately . The other object is finding anyone who has one stocked and t9 have a custom made will be some $ . Last one I did I was lucky the unit was over 50 years old and I was able to get a exact replacement through carrier it was sitting in a warehouse in Kentucky from like 1976 and surprisedly it was about 1/3 the price of getting one made w the shipping and I had it in about 3 days . This is why sometimes it pays to go w the larger manafactures like carrier / trane being it’s sometimes easier to get oem coils ,blower shafts bearings for equiptment that’s ancient While the other guys don’t have and favor complete replacement which in some cases is beyond reasonable . As always great article peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • Jackmartin
    Jackmartin Member Posts: 196
    edited November 2022
    So true went to a single pipe job that had just had two  new Wiel Mclean boilers, the genius that sized the header drain trap put in a two inch f and t. Needless to say the 1000.00 dollar trap came out and a one inch with lots of static on it installed to the , get this, 600 gallon condensate tank for a total 40 boiler horsepower. This was an engineered job signed by the engineer on top of his professionals stamp, he must of been at the bottom of his class. No. I do not have anything against engineers my eldest son is a professional electrical engineer, he was not at the bottom of his class I can assure you. 
    Cheers Jack  
  • pedmec
    pedmec Member Posts: 994
    Years ago went to look at a leak on a steam coil leak that one of our techs was at the previous day. He was replacing the f&t trap. It was feeding the steam coil with district steam for make-up air. I could walk in the ductwork it was so big. Talk about a mistake. Our tech forgot to open up the gate valve to the condensate pump and all the condensate froze in the coil causing the coil to split EVERYWHERE. My boss wasn't contracted to fix the coil so we left the site so i don't know what ever happened. There were so many splits I can't believe they would try and repair it but then the location to get a new coil was just as problematic. My boss at the time had me leave. It was only my second year in the industry so i didn't ask questions.