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Buderus g115/4 low limit

kato248 Member Posts: 2
Boiler does not keep low limit, Aquastat and 120v relay (taco sr504) replaced when zone calls boiler runs when nothing calls (water/heat) boiler shutdown 


    HVACNUT Member Posts: 5,268
    edited April 2022
    Well thanks for the comma and parenthesis anyway. 
    You late for a plane or something?
    The aquastat and the SR504 were replaced?
    What model aquastat?
    Is it wired XX dry contacts on the SR504 to TT on the aquastat or using ZR,ZC?

  • kato248
    kato248 Member Posts: 2
    Wired xx dry contacts to thermostat on Aquastat l8148 Honeywell thanks for any help Jim 
    HVACNUT Member Posts: 5,268
    Well the L8148 is just a high limit aquastat. There isn't a low, just a fixed differential off the high. It will energize B1 and C1 when TT closes. B1 opens on limit. If no zones call, the boiler goes cold.