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Modulation Range - Burnham Alpine

Chotu Member Posts: 14
Per the I/O manual - Burnham Alpine 150 Boiler modulates between 30 to 150 MBH input.  Is it possible to have it modulate, lets say between 10 to 150 MBH?  Perhaps via the Gas Valve (Dungs GB-WND 055) throttle adjustment.  I have a small zone and would like the boiler to modulate down to meet its small heat demand with minimal cycling.


  • meplumber
    meplumber Member Posts: 678

    The modulation range of negative pressure gas systems is determined by the minimum allowable fan speed.  Most of the fans can't be run below 20% of full HZ.  Thus the industry standard of 5 to 1 turn down ratios.

    IBC had a boiler with a 10 to 1 turndown, but I am not sure what they were doing different.

    A buffer tank or true hydronic separation is your best option.
  • meplumber
    meplumber Member Posts: 678
    edited March 2012
    Duplicate Post

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