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lwco

DaveM
DaveM Member Posts: 39
is it recommended to have a guard dog low water cut off on a oil fired hydronic boiler with a L7248 triple aquastat control

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 19,152
    I;d certainly want something on there to ensure that it couldn't fire if the system drained and the automatic feed failes...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    DaveM
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 3,336
    edited March 31
    It has been part of the "Required by Code" for many years. They only started enforcing it for the last 15 years or so in NJ. and other States. The Back-Flow preventer was also never enforced in the 1970s and 80s. In the late 80s that became the "Failure du Jour". I have seen Back-flow preventers and LWCOs on hydronic (not steam) boiler in the 60s and 70s but it was few and far between. I remember asking the chief boiler installer for my father's company in the late 1970s why don't we install LWCOs on all our new boiler installs? His reply was: "You don't need them if you put on an auto water feed".

    That is the way I was taught! We also installed Circulators on the return and the cold water feed must be on the return (before or after the pump) with the expansion tank on the supply. Never had a problem with that either. (Until I did LOL). Then I was learned by @DanHolohan. He teached me good!
    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org
  • HVACNUT
    HVACNUT Member Posts: 4,624
    If it can't be easily piped in, you can change the aquastat to a Hydrostat 3250 Plus with their well for LWCO protection and other features. 
    STEVEusaPAGGross
  • DaveM
    DaveM Member Posts: 39
    thanks Ed how was the wedding
  • DaveM
    DaveM Member Posts: 39
    hvacnut thats a great idea im going to look into that control
  • leonz
    leonz Member Posts: 530
    edited April 2
    My past experience with the hydrolevel 3250 was nearly fatal as the boiler nearly boiled dry on me.

    The replacement hydrolevel 3250 unit had a mind its own and as I was running the boiler it turned the low water cut off function off.

    I have a Bell and Gossett/McDonnel and Miller RB-122-E and I have slept well ever since.
  • MikeAmann
    MikeAmann Member Posts: 434

    We also installed Circulators on the return and the cold water feed must be on the return (before or after the pump) with the expansion tank on the supply. Never had a problem with that either. (Until I did LOL). Then I was learned by @DanHolohan. He teached me good!

    My system is piped as you described. Why is it now wrong? Do you have a link that I can read on this?

  • leonz
    leonz Member Posts: 530
    According to the installation and maintenance literature for the RB-122-E it can be installed in the close boiler piping as well which requires a tee for the sensor WITH NO TAPE OR PASTE to seal it as the sensor will be affected by the tape/paste and will not sense the water level correctly.