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honeywell pressuertrol wiring diagrm for oil fired stea boiler with MMPS801 LWCO

replaced old gaurd ring lwco on Burnam v1 boiler with PS801 LWCO cant figuer out how to wire the pressuretrol also has aqastat and indirect water heater, everything works as far as the boiler firing for heat and hot water wired according to wiring dia. I tryed wiring it in series with the tstat wireing back to tt on the primary but boiler wouldnt fire, tried splitting the power L1 through the pressuretrol then to the LWCO but that wouldnt send power to LWCO I assumed the pressuretrol was normally closed and open on pressure am I wrong.


  • Paul S_3
    Paul S_3 Member Posts: 1,261
    edited April 2016
    No you are correct its normally closed and opens on a rise in pressure. Split the wire coming out of terminal B on the lwco and run it through ptrol....that is your burner circuit....you cannot break the tstat wire because the aquastat for indirect is wired in parallel on T&T on primary control....and are you sure ptrol isnt stuck in the open position?
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