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Triple function aquastat- temp setting help needed

john58 Member Posts: 7
I have installed theL6081A 1010 Honeywell to control the circulator pump to run only on call for heat when the boiler water is above a preset temp. The circulator used to run constantly. 3/4 HP motor- 24 hours per day during the entire heating season here in western PA. -Costly!  I'm setting the Hi limit at 180. What should I set the Low limit at or is it OK to let the boiler cool down on night set back until a call for heat after several hours later?  Is this cooldown hard on the boiler?  Ideal differential settings???

Obviously needing help. John 58.


  • GBriggs
    GBriggs Member Posts: 15
    L6081 ?

    HI John,

    I am not sure you understand how this control works. The High limit has a 10 degree fixed differential that is subtracted from its set point. You can not adjust this. Example 180 set point circuit opens R to B if the water temp drops 10 degrees to 170 then the High limit again makes its contact R to B. This High limit uses a SPST switch.

    The Low limit has an adjustable differential of 10 to 25 degrees. Using the 10 degree setting it operates like the High limit but uses a SPDT ( RWB ) switch to control a zone and circulator. If you dial in more that 10 degrees say 15 degrees the switch always drops 10 degrees but then rises 15 degrees before the switch changes position. Most boilers will allow settings of 150 degrees before you would see an issue. Check with your boiler rep for an exact low setting.
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