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Power to each pump has cut off switch separate from boiler; whhy?

MaMa Member Posts: 18
The pumps for each of my three zones running out of my Buderus G124X has its own power switch, creating the ability to turn the circulation pump etc for each zone on

independently of each other & of the boiler itself. In other words I have four switches in the furnace area, one controlling the boiler and the other three each controlling one zone pump & valve.   Each zone is also controlled by a wall thermostat, and each thermostat appears to be running into the wiring boxes for each of the three zones.  There is nothing connected to the Circulator C1 and C2 terminals on the L8148E aquastat.  I don't know if this is typical or not.

What is the point of not running the power to the pumps through the same switch as the boiler?  To have a second way of turning individual zones off in addition to using the thermostat?  And, am I correct that there is no reason I would ever want any of those three switches to be left on when the boiler switch is off?  In fact it may be a bad thing if they are left on & somehow the thermostat makes a call for heat when the boiler is off?

Just thought I might learn something through figuring out the "why" of this setup.


  • lchmb
    lchmb Member Posts: 2,997

    It wouldnt actually hurt the circulator to run if the boiler is switched off as long as it has water in it. The only concern would be if someone is servicing it and thinks the power is off with the switch at the boiler (grabs a live line). I have a number of system's that are wired this way and have alway's been told it's to make them easier to service, dont have to shut everything down to replace one circulator. If I ever have to work on the wiring side I generally do away with it. I like one switch to shut it all down. The worst thing would be if someone switched one off in the extreme cold and froze a zone...
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