skip to main content

Air Compressor Req't for Irrigation System Winterization

18 years ago

I have a new irrigation system. I'm thinking to buy an air compressor so I can blow it out (winterize) it myself. Other than that, I'll only use the compressor for simple things like inflating tires.

Question - will a low-cost Sears compressor (Model 15310, approx. $100) be sufficient to blow out my system? This compressor is rated 125 psi max and delivers 2.4 SCFM.

Thank you

Gary

Sort by:Oldest

Comments (6)

bsparks294
18 years ago
I can provide you with some information regarding this subject.

I recently bought the identical compressor for just that purpose. The problem is with the size of the tank. It cannot hold enough air to keep the pressure up. On top of that the compressor cannot produce enough air to keep up with the outflow into the sprinkler system.

There is one way to aid this process though. If your lines are extremely long (75-100 feet), then I do not think you would be happy with this compressor. But if the run is relatively short, then if you have pop-up heads that only spray when they are up; just put a rock or something on top of all but one in the line that you are spraying out and this alleviates some of the problems of pressure falling too fast. You are in essence just blowing the water out of one sprinkler (not valve) at a time.

Hope that information helps. I ended up getting a compressor with a larger tank and love it. But of course it was three times as expensive--so that will not work for everyone.

Good luck, Brad
garyblack
Original Author
18 years ago
Brad

Thanks for the good advice. Question - exactly what size of compressor did you settle on (gallons and CFM)? In your opinion, was it just the size you needed, or slighly too big or too small? As I understand, those parameters are more important to blowing out my irrigation system than is the psi value.

Thanks
Gary
Related Discussions
Why is a 20+ compressor needed to winterize water lines?
Q
Comments (16)
madtripper, The point I was trying to make was the difference in pressure. One shot from a blow gun at 125 psi would empty the glass instantly. But that's because the liquid in the glass is in a small, confined space. The people in the irrigation industry mostly rent tow-behind compressors that put out 125 to 200 CFM when they winterize systems for their customers. They know from experience that high volumes of air blowing through the underground pipes will clear 99.9% of the water in a matter of seconds. Small CFM compressors cannot sustain even 90 psi for very long. The pressure drops off quickly to the cut-in point also because these compressors have very small air receivers. And the larger the hose diameter you use, the faster this happens and the harder it is for the pump to play catch-up. As air is blown into the water lines using one of these little compressors, water does indeed escape. However, as the water escapes, the level of the water in those pipes also drops and that creates an airspace above the water level which allows the air to take the easy route in finding an exit. The initial blast of air gets the much heavier water moving in the pipes. As the water moves along, it creates a space that must be taken up by the air. Water is not compressable. Air is. You need to keep this now-moving-water moving at a rate that is sufficient to have it rise vertically and exit the sprinkler heads in totality. If the water pools in the elbow at the bottom of the sprinkler head, then it will freeze and break the elbow. Next spring, it's repair time. Therefore, it is difficult to ensure that all the water has been removed from the system when using small CFM compressors. And since the whole object of the exercise is to remove the water to prevent freeze damage, then using a compressor with adequate volume (CFM) seems appropriate. To me, this akin to saying the following. I need to winterize my cottage but I didn't buy enough RV antifreeze, so do you think I will be OK if I put only half as much anti-freeze in each toilet as written in the instructions? You asked a question. Several people have told you how the Pros do it. It's your system, your dime. If you believe that you can blow it out with your compressor, then by all means, go for it. The proof is something that will be found next spring and every spring thereafter. Underground systems can be simple or quite complex. If you can simplify the system by isolating branches, then that might work. You have the luxury of time that a PRO does not. He needs to get in and get out quick in order to keep the cost down. To a degree, it's an apple and oranges thing. But either way, if water remains, so does the potential for damage.
...See More
Winterizing irrigation sys can blow air thru backflow preventer?
Q
Comments (1)
anyone have any thoughts?
...See More
winterize sprinkler system/air compressor??
Q
Comments (8)
Winterization of your sprinkler system is not an area that I would suggest skimping on, particularly up here where it gets cold. If you search around you will find that the recommended compressor stats (for simple residential sprinkler system blowouts) are 10-25CFM at 60-80 PSI, a little further research and you will find that a compressor of this type is LARGE and EXPENSIVE, $1000.00+. Vastly more than you would ever need for blowing up pool toys and bike tires. The volume of air is the crux for consumer grade compressors they just do not move *enough* air to clear the lines completely, the air will override the water leaving the pipe partially full of water, which accumulates in the low areas, and freezes... I know a few folks who use their home compressors and have had no problems, I have also reinstalled systems where the freeze damage was so extensive replacement was the only cost effective approach. BELIEVE me I am a do-it-yourself homeowner, in fact I just this weekend completed replacement of 50' of my house foundation which was do it yourself to the extreme. It is my opinion that winterization by a proffesional is well worth the money. Good luck
...See More
Air Compressor or Air Blower to Get Water out of Drip System?
Q
Comments (1)
I use compressed air to winterize our irrigation system. I can't imagine how a 'blower' would do an adequate job. Every fall, I disconnect the water supply and remove the zone valves (we freeze here in the winter). One end of a 1/2" drip line ends near our garage so I have made hose jumpers that I install between my compressed air supply and this drip line, and between the zone feed lines at the control valve box. I drop my compressed air supply to 30 psi and let it blow out the system for at least 20minutes, then disconnect the jumper hoses and store them for next year.
...See More
mrpike
18 years ago
It depends on what your definition of an acceptable job is.

As a rule of thumb, it should probably have wheels if you want to use it for this. Or you could buy a separate air tank and fill it with your small pump, empty it, refill it, empty it etc.

I use a compressor powered by a 4 cyl desiel.

I have seen a few in the 5-7 HP range that could do an job close to professional, but like I said, it all depends on what you are trying to accomplish.
garyblack
Original Author
18 years ago
mrpike - thanks for the feedback. Basically, all I want to be able to do is to blow out one zone (5-6 heads) at one time. I don't care if it takes longer than a high-power compressor would. I'll only be doing it once a year. Other than blowing out my system, the only other thing I'll be using it for are simple things like inflating tires, etc. By the way, I do have one acre to irrigate, and so I imagine that my pipes are rather long. But again, as long as I can blow out one entire zone (albeit it slowly), then I'll be happy. I just don't want to do one head at a time while blocking the air (using a rock, etc.) from the other heads in the same zone as the previous post mentioned.

Given that, what CFM, gallon tank size and psi would I need for the compressor?

Thanks again for the advice!
Gary
mrpike
18 years ago
The problem with using a small air compressor, is when the water clears the first head, most of the small amount of air you are able to push starts to exit the zone. Then you don't have enough CFM to keep pushing the water out the far heads.

The compressors that the pros use is pushing 100+ CFM. At 40-80 psi normally. Large volume, lower pressure.

Will a $100 compressor get water out of the pipes? Sure, just not as much. As long as most the water leaves the heads, and the mains and laterals are not completely full, you will probably be fine.

If you are shopping, get something with a larger tank if you can, if you have only got the budget and room for a small one, well that is fine too. Just fill the system in bursts. Hook up a valve on your hose before the sprinkler. Release all the stored air, once you are down to 10 lbs of pressure,shut the valve. Let the system pump back up and then release the air again. Another option, is to connect an additional air tank in line with the above setup. It will give you more cubic feet of compressed air available. Something like this.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40057
You could then use a smaller compressor, store up a bunch of air to release all at once.
HU-385145370
last year
Definitely not enough cmf need at least 50 to 70 cmf depending on how big your system is. It depending on size of pipes how long of a run of the pipe are from the water source. If you don't do it properly you will have problems in spring

Related Stories

MOST POPULAR 5 Ways to Hide That Big Air Conditioner in Your Yard

By Mariana Pickering (Emu Building Science)

Don’t sweat that boxy A/C unit. Here’s how to place it out of sight and out of mind

DECORATING GUIDES 10 Ways to Hide That Air Conditioner

By Mariana Pickering (Emu Building Science)

Feeling boxed in designing around your mini-split air conditioner? Try one of these clever disguises and distractions

GREAT HOME PROJECTS How to Add a Radiant Heat System

By Mariana Pickering (Emu Building Science)

Enjoy comfy, consistent temperatures and maybe even energy savings with hydronic heating and cooling

LIFE 6 Ways to Cool Off Without Air Conditioning

By Mariana Pickering (Emu Building Science)

These methods can reduce temperatures in the home and save on energy bills

EARTH DAY Grow a Beautiful Garden With Ecofriendly Greywater

By Greywater Corps

Reducing home water waste means lower bills and a healthier planet. Here's how to set up a greywater home irrigation system that can help

MONTHLY HOME CHECKLISTS To-Dos: Your April Home Checklist

By Laura Gaskill

Kick spring cleaning into high gear, and troubleshoot cooling and irrigation systems for the warmer months ahead

SAVING WATER 6 Reasons Why You Should Save Your Rainwater Now

By Falon Mihalic

Collect and store during the rainy season so you’ll have water ready for irrigation when you need it

GREEN BUILDING How to Harvest Rainwater for Your Garden

By Mariana Pickering (Emu Building Science)

Conserve a vital resource and save money by collecting stormwater for irrigation in a barrel or tank

LANDSCAPE DESIGN Ditch the Ordinary Ditch: Create a Realistic Dry Creek Bed

By Jay Sifford Garden Design

Here’s how to turn your water runoff system into an eye-catching accent for your landscape

GARDENING GUIDES Southwest Gardener's September Checklist

Arid desert gardens get welcome relief this month with cooler temperatures and moisture in the air. Here's how to make sure they thrive

0

Sponsored

More Discussions

Bower's Vine Leaves Limping

9

Renovating drip system-a question for those with experience

12

What threads does the Orbit B-hyve XD with 4 outputs have?

0

Your experinces with expandable garden hoses

0

Fertilizer injector on siphon valve turned to drip irrigation

1