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Lochinvar KBN 106 T-stat connection for C wire??

JUGHNE Member Posts: 11,062
I have a couple of these KBN's with simple R-W control.
I did call tech support some time ago about getting a common connection for HW tstats, he said that Lochinvar did't want the common used for this purpose. I don't think he understood the question and really have a good answer.
I see there is a common connection for louver relay coil if used.
Don't want to risk a $5-$600 board.

So these boilers are running on batteries which is a minor hassle. Also to explain to the owner why the heat failed on their $XXXX.00 replacement boiler is awkward. Even though the tstat flashes the low bat message early enough this gets overlooked over the summer.

I am sure this has come up before.
So is the best solution a separate 24 vac transformer with an isolation relay?
I have more than enough conductors at tstat.
I just hate to add another control device/gizmo in any system.


  • Alan (California Radiant) Forbes
    Pretty simple to slide in a SR501 transformer relay for your "C" power. To me, it makes things a lot simpler than to use the boiler circuit board. And I can understand why a boiler manufacturer doesn't want you messing with their board.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    JUGHNE Member Posts: 11,062
    Thanks, I was my first guess. So another relay. :/