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Knight KBN500 Cascade problem

The other problem is when we have the setpoint at 185 or higher, it locks out. 183, no problem.


  • Dan Keirns
    Dan Keirns Member Posts: 4
    FYI on cascading Knight KBN500 boilers

    We have 2 seperate instances of KBN500 Knight boilers in cascade mode that do not function properly. What the lead boiler does is lock out on auto reset high limit and won't reset. Lochinvar says they have a fix coming in a couple of weeks for this. They also say it is only the 500's that are affected. The fix will be in the form of a new integrated control board for the lead boiler.
    In the mean time, to get you by, take the boilers out of cascade mode and run them as seperate fixed setpoint boilers. Disconnect the system sensor and outdoor reset and make sure you jump the R & W terminals on all the low voltage boards.
    This is the only chink in this Knights armor that I've found so far!
    Just a heads up for everyone.
  • Dan Keirns
    Dan Keirns Member Posts: 4

    The thing I have discovered, especially running on high temp, is to lower the SH Offset from the 10 degree default to 5 or less.
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