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Screen over exhaust pipe?

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sunlight33
sunlight33 Member Posts: 378
in THE MAIN WALL
Do people usually put a varmint screen over exhaust pipe of a mod-con boiler? If the holes are sufficiently big enough (1/4'' by 1/4'') there shouldn't be any issue with ice formed from condensation right?

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  • kcopp
    kcopp Member Posts: 4,448
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    Screen is a requirement....
    Ice should not be an issue....
    hence the reason you should pitch the vent back to the boiler.
  • GW
    GW Member Posts: 4,736
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    We've had issues with blocked intake in cretain winter conditions with 2" pipe. Very cold and snow flurries and blockage can happen. I've seen in several times.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • kcopp
    kcopp Member Posts: 4,448
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    GW said:

    We've had issues with blocked intake in cretain winter conditions with 2" pipe. Very cold and snow flurries and blockage can happen. I've seen in several times.

    GW said:

    We've had issues with blocked intake in cretain winter conditions with 2" pipe. Very cold and snow flurries and blockage can happen. I've seen in several times.

    What sort of conditions? How far off the ground?
  • GW
    GW Member Posts: 4,736
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    Well above the snow line, I'm not talking snowed in. Super cold (single digits and lower) and moist conditions (snow), and we are on it. "Can you please walk out to the pipes outside, see if the pipes are free of frost buildup? Ok, do you have a screwdriver or something to pry the screen out? It should pop right out. Ok press the reset button. Are the numbers starting to climb? "

    It's a pain. Our furnace installs don't have screens.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
    Bob Bona_4
  • ced48
    ced48 Member Posts: 469
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    At -10, even with a back pitched pipe, my WH55 had some ice build up in the bottom of it's 2" exhaust, not enough to be a problem, but there. I doubt the screen was the cause, just so darned cold.
  • kcopp
    kcopp Member Posts: 4,448
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    So do think that keeping the vent and intake to 3" is the way to go?
  • ced48
    ced48 Member Posts: 469
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    Only if the boiler calls for 3", if it calls for 2", you should use 2".
    These boilers require a certain amount of pressure to operate correctly, using larger pipe opens the door for problems.
  • kcopp
    kcopp Member Posts: 4,448
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    Most give you both options.
  • Jason_13
    Jason_13 Member Posts: 304
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    I have also seen the air intake freeze over which is normally caused by cross contamination.
  • kcopp
    kcopp Member Posts: 4,448
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    Jason said:

    I have also seen the air intake freeze over which is normally caused by cross contamination.

    Hence the reason I hate concentric venting.
    SWEI

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