Air Compressor Size for Winterizing

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Flipperman2a2w, Sep 15, 2011.

  1. Flipperman2a2w

    Flipperman2a2w New Member

    Messages:
    33
    Location:
    North Carolina
    There have been quite a few posts on compressor sizing to blow out sprinkler system pipes, but I haven’t had much luck finding information on compressor size for winterizing a home. . . It seems like a small home would have less piping than a sprinkler system?

    I have a 1200 Sq. Ft. one-story cabin with 2 bedrooms and 2 bathrooms on a private well. The piping in the crawl space is all ¾†PEX.

    I would like to purchase an American made air compressor, as I’ve just read horror stories about the cheap ones that can be purchased at Harbor Freight. I guess the old adage is true- you get what you pay for.

    That having been said, most of the American made compressors are BIG. North Star, Ingersoll Rand, Quincy, and Chicago Pneumatic are mostly 20-30 gallon+ units. Those are all fairly expensive and seem like they might be overkill.

    I’m considering the Ingersoll Rand Twin-Stack Air Compressor — 2 HP, 4-Gallon Capacity, 4.3 CFM @ 90PSI, Model# P1IU-A9 for about $359. This looks to be the smallest unit made by IR, but I’m concerned about the capacity and CFM being great enough for my task. . .

    The next step up is the Ingersoll Rand Garage Mate — 2 HP, 20-Gallon Capacity, 5.2 CFM@ 90PSI, Model# P1.5IU-A9. This unit is obviously bigger and (consequently) more expensive by about $200.

    Thoughts?
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,004
    Location:
    NW Ontario, Canada
    Unless you can utilize a good size bladder tank to build up with air on the water side, you will need the 20 gallon capacity. I have a small 4 gallon tank on my compressor and it's too small for just blowing out my underground lines.
  3. Flipperman2a2w

    Flipperman2a2w New Member

    Messages:
    33
    Location:
    North Carolina
    Thanks so much for the reply. I kind of figured it would probably be too small :( Looks like I'm going to have to upgrade to the larger model. It seems kind of crazy laying down that kind of cash to ensure that my pipes don't rupture in the cold, but I can't imagine the feeling of turning the well pump on in the summer and hearing the sound of running water under the house. . .
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    Given the small volume of the piping in a residence, and the VERY small pressure required to push the water out of the piping, a small 5 gallon compressor is MORE than adequate for the task, especially if it has power and continues to pump even when the tank is almost empty. The real secret, and question, is HOW you go about doing the winterizing.
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,004
    Location:
    NW Ontario, Canada
    In my home, all the supply lines after the pressure tank are copper and properly pitched to be able to drain. There are very few spots where small amounts of water may remain. If I first drain all the lines, then close all the stops and pressurize the lines with air, the volume of air in the lines is adequate to blow out the residual.

    Where my compressor comes up short are my outside underground poly pipes since they are not pitched to drain. I have to repeatedly air them up, purge, and air them up again, each time blowing out less and less water.
  6. BobL43

    BobL43 DIY Senior Member

    Messages:
    1,793
    Location:
    Long Island, NY
    Same here; my "2 HP " C&H 11 gallon compressor just does not have enough volume to push all the water out of the long run poly pipes to get all the water out in one purge per zone. The closer heads clear first and unless I cap them off, they piss out all the pressure and leave less for the more distant ones. The guys that go around with gas engine driven compressors on their trucks can blow out all the zones on a residential system at once. Looks like 50 gallon tanks on theose trucks. Of course that is overkill for a homeowner, but in my experience, my 11 gallon tank is not an ideal size for this application. It WILL get the job done in 2 or 3 attempts per zone though.
  7. Daveh

    Daveh New Member

    Messages:
    1
    Location:
    Idaho
    The local commercial guys usually rent a towable gas or diesel powered air compressor, but thats mostly for time saving as they would want to get the job done quickly as possible.

    A small cabin I would think you would have to blow out & recharge one section at a time using a 1 to 2 hp compressor with a 15 or 20 gallon tank.

    Surprisingly there are still quite a few American compressors companies around...http://usamadeproducts.biz/air-compressors.html
  8. pitterpat

    pitterpat HandyWOMAN

    Messages:
    46
    Location:
    Indianapolis
    Why not just rent a compressor when u want to do the job....$50/time cover abt 4 yrs.
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