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bleeding radiators (oil/hot water system)

hh409 Member Posts: 14
hello - need to bleed the radiators and have some questions please

my system heats a smaller single story home, the boiler pumps hot water out to a "T" where it goes on to feed 4 old cast iron type radiators in series on each side of the house (8 radiators total, 4 on each side, 2 independent legs simultaneously being supplied from the "T") there is also a circulation pump in the system.

1)does the system need to be on and water in circulation during the process?

2)if circulation is not necessary should the system be hot or cold? does it matter?

3)which radiator should be done first? the one farthest from the boiler or the one closest?

4)which leg should be done first? i am assuming based on the system layout it does not matter

thank you for the help


  • Paul S_3
    Paul S_3 Member Posts: 1,257
    edited October 2013

    To bleed the radiators just make sure the boiler has shouldn't need much on a single story home factory set 12psi from reducing valve should be fine....I would have the system off when bleeding the or cold doesn't make a you always have air problems? And you can start with any radiator.....Paul s
    ASM Mechanical Company
    Located in Staten Island NY
    Servicing all 5 boroughs of NYC.
    [email protected]
  • hh409
    hh409 Member Posts: 14
    bleeding radiators

    the radiators feel hot, naturally the last one on the loop never feels as hot as the first but it is still the same reasonably hot

    i have not noticed anything irregular and the system has not received any "major" maintenance where water would get into the system.

    however, i know the system has not been bled in YEARS, probably 15 or so.

    would an occasional bleeding benefit the system or is it best to let it be if nothing seems wrong?

    thank you
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