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replacing a sensor

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remodel
remodel Member Posts: 68
in THE MAIN WALL
Guys, I have to replace an outlet sensor in a WHN loch 155.  I have to drain the heat exchanger.  There is plenty of isolation valves.  Any pointers.  Thanks    

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  • Steve Whitbeck
    Steve Whitbeck Member Posts: 669
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    quick

    If you can isolate the boiler with valves, then drop the water pressure of the boiler to 0 with the relief valve, then just prep the new sensor and do it quick. UNLESS water can get on any electronics.
  • remodel
    remodel Member Posts: 68
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    ok

    Ok, I also have some low drain valves on the bottom of my boiler pump loop and closely spaced tee/system loop, they are the two low points on the p/s piping.  Should I just use those instead of PReV?  Should I shut off makeup water as well?  Also when you say prep.....sensor has a small gasket, should I also dope the threads, it is just a standard brass threaded piece with electric connection on backside?  Thanks Steve.  Waiting for the weekend just incase there is an issue on startup.     
  • remodel
    remodel Member Posts: 68
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    question

    When I refill and slowly open everything up should I wait an hour for the HX to cool off or with this mod/con no worries?  I have one vertical pump so I will pressurize to 20psi.  Anything I need to know on the LWCO or once I refill, should have no issue.      

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