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Venting behavior at startup

When my boiler starts at the beginning of a cycle there is a brief, loud hiss from all of the vents (main and radiator) that lasts for only a few seconds.

Comments

  • bml207bml207 Posts: 27
    contd.

    This lasts less than 5 seconds and happens 2 min after the thermostat clicks on, every time.

    The pressure during venting is around 2 oz. on my 0-3 psi gauge, so I don't think it's under-vented. The radiator vents are a mix of Gorton 6's and C's, sized according to the balancing e-book. Any idea how to get rid of this noise? Thanks.
  • BobCBobC Posts: 4,956Member
    Hisss

    What kind of main vents are you using and are your radiator runouts very long?



    Even though the back pressure is low it sounds like you might need more main venting.



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • bml207bml207 Posts: 27
    edited January 2013
    Main Vents

    The main vents are 1 Gorton 2 and 1 Hoffman 75. The main is about 55 feet of 2 inch pipe.



    Many of my run-outs are about 12 feet long, even on the first floor.



    Thanks.
  • bml207bml207 Posts: 27
    edited January 2013
  • BobCBobC Posts: 4,956Member
    Wet steam?

    You should have enough main venting. You might try a fast vent (Gorton c or d) on the input of a radiator and small radiator (4 or 5) on the radiator itself. On the long basement runs you could drill and tap a 1/8" hole on the side of a radiator riser of one first floor radiator and try the fast vent there to see if it quiets that one radiator. make sure you have room to thread the vent in.



    Do you think you might have wet steam?



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • bml207bml207 Posts: 27
    Wet Steam

    Maybe. This is a fairly new boiler, but I think I got most of the oil out of the system by now. The water line doesn't fluctuate much when it's making steam, maybe plus or minus half an inch.



    There is only one riser from the boiler to the header. I would guess this is more likely to produce wet steam than if both boiler tappings were used. The boiler and risers seem to meet all the Dunkirk specs.
  • BobCBobC Posts: 4,956Member
    Dunkirk?

    I seem to recall Dunkirks producing wet steam unless both boiler outlets are used. With over 400 sq ft of EDR using both boiler outlets seems prudent.



    Perhaps someone more familiar with Dunkirks will weigh in on this.



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • bml207bml207 Posts: 27
    Dunkirk

    The manual does show that it is ok to install with one riser seemingly without any regard to size. It was installed before I moved in or I would have insisted on two.



    Thanks.
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