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Veissman in the U.K.

Tim_9 Member Posts: 24
I am looking into replacing my old Buderus 124x with a Veissman 200-W 35. After searching around I noticed the 200's in the U.K. have a 20:1 turn down ratio vs. 6:1 in the states? Pretty big difference, any reason for this? Anyone have any luck shipping one of those over here? Thanks in advance...


  • NYplumber
    NYplumber Member Posts: 503
    good luck finding a replacement part.

    Why not just size the boiler correctly and use a proper buffer tank size? This would eliminate the need for 20:1 turn down ratio.
  • Tim_9
    Tim_9 Member Posts: 24
    Just seems a 20:1 turn down would be so much cleaner/less hassle, but you are right replacing parts would be a pain.

    I think another problem would be the European line voltage frequency of 50HZ vs 60HZ in the U.S., which would effect the speed of synchronous motors. Anyone know which type of motor Veissman uses?
  • Henry
    Henry Member Posts: 996
    The rules for boiler certification was at one point 5 to 1. With much effort over the years, it was now accepted for certain boilers at 10 to 1. It might take NA at least 10 more years to accept 20 to 1.
  • Eric_6
    Eric_6 Member Posts: 25
    Many Commercial boilers that are 20:1 and even a few at 25:1 available in USA. The problem with going farther than 10:1 is the amount of excess air needed at the lower end to make it safe combustion. These boilers typically lose efficiency at the low end when they should be at their highest efficiency. There are a few now with essentially multiple boilers under one casing to get that 20:1 turndown (Viessmann being one) and still have optimum efficiency at the lower firing rate. Pick a high mass boiler at 5-10:1 or a watertube type with buffer tank.