Compressor to winterize sprinkler system

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IamAllThumbs

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It always chafes at me to pay someone to do stuff unless it requires skills or specialized tools I don't have.
Blowing out sprinkler lines doesn't require much in ways of skills but I don't own a compressor (I've got a tiny pancake one for painting my fence).

In my area, I now need to pay someone anywhere between $100-$150 to get the sprinkler done, and the scheduling is a pain.

Are three reasonably priced compressors that might be worth buying for me to recoup the price over a handful of years?

It seems I need a 20-50 CFM at 50.PSI for 5 minutes. I'm compressor terms that seems quite beefy although I know very little about them. What I found was in the $3500 range, probably an order.of magnitude of what I'd like to spend ($300-$500) or I will rather stick with rh guy that currently does it for me.

Am I overspecing the compressor needs?

Residential sprinkler system, 5 zones over relatively short distances (small front and back yard). I think the pipes are 3/4" but can't swear to it. Rainbird residential sprinkler heads.
 

bud16415

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I would give the pancake a try. If you had a larger tank you could pump up to add a little more volume that wouldn’t hurt. I have a used propane bottle I converted to a extra air storage tank that some people thought I was nuts doing but it worked well when my main compressor was smaller than what I have now. I believe the propane tanks are rated to 300psi. The one I used I went to get it filled and was told it was out of date as there is some law they can only fill them based on the date code. The guy wanted me to leave it and buy a new one. I bought a new one but kept the old tank.



Harbor Freight has some not to bad mid sized units for about 300 bucks that are ok compressors. Or keep your eye out for a used one.



I have outside water lines that amount to about 150’ of .5 garden hoses hooked together with some T connectors and about this time every fall I switch the Ts to make one long path and disconnect it from the house and blow it clear of water with my compressor. I also blow out my pressure washer for winter.
 

Sparky617

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I would give the pancake a try. If you had a larger tank you could pump up to add a little more volume that wouldn’t hurt. I have a used propane bottle I converted to a extra air storage tank that some people thought I was nuts doing but it worked well when my main compressor was smaller than what I have now. I believe the propane tanks are rated to 300psi. The one I used I went to get it filled and was told it was out of date as there is some law they can only fill them based on the date code. The guy wanted me to leave it and buy a new one. I bought a new one but kept the old tank.



Harbor Freight has some not to bad mid sized units for about 300 bucks that are ok compressors. Or keep your eye out for a used one.



I have outside water lines that amount to about 150’ of .5 garden hoses hooked together with some T connectors and about this time every fall I switch the Ts to make one long path and disconnect it from the house and blow it clear of water with my compressor. I also blow out my pressure washer for winter.
This site (a seller of compressors) says home units don't have the air volume to handle it. No experience with sprinklers, and I think around here people just pull the check valves off and let it go. If the lines are placed over a foot down they are past the frost line in this part of the state (NC).

 

bud16415

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I believe there is PEX line made to and oval or football shape that is designed to take the expansion of static water freeze. I remember reading about it a long while back. Around here some kind of a blowout would be required our frost line is below 4 ft and cemeteries used to have buildings to hold burials over until spring in the days of hand dug graves because it was just imposable to dig. The county I live in I don’t even trust the 4’ depth and one reason I built my deck free standing. My mud room is at the 4’ depth and every few winters the door starts sticking with some movement.



I don’t know how fragile the yard tubing and sprinkler heads are when I worked at a golf course many years ago we used to blow out the entire course each fall with a huge truck mounted compressor. Like I said I blow out my coiled and laid out garden hoses and I don’t even use a fitting I just jam my blow gun in the end figuring that is a good back pressure measure. When I do it I’m blowing out 50’ coiled then 50’ straight then a two way splitter and then 50’ coiled. Then I have another 50’ run that goes into the garage and up to the ceiling and back down the other side to get water to the garden. It mostly self drains but I give it a shot as well. I thought about burying PEX and doing it correctly but all of these runs are hidden in gardens and it is a lot easier to find a leak when above ground and hose is cheap.



IMO it doesn’t take a lot of air or much pressure to get most of the water out. In my case I don’t care if a little stays in as long as if it freezes it can expand.
 

Sparky617

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I believe PEX can withstand freezing, the fittings maybe not. They seem to use CPVC here for sprinkers.

For blowing out your hose by mouth, try doing it uphill. I run mine down hill and unhook them from the hose bib and let them flow out when storing for the winter. I bring the hoses in for the winter, so I can on a nice day wash my car in the driveway. A frozen hose tends to stay frozen here during a warmish winter day, don't ask me how I know... It isn't unusual for us to have a 40 degree F temperature swing in the winter. From 20 to 60 isn't unusual. Long hard freezes are rare, but can happen.
 

guest2

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Where do you live and how deep are you water lines? I put a self drain / automatic drain on the low side of the zone and they drain every time so no winterizing is needed.
 

IamAllThumbs

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Colorado. I don't know how deep the lines are, I've only dealt with replacing heads off the "stems" off the buried line, but the valve box is less than 2 feet deep. There isn't a drain line that I'm aware of, so even if I were to open the lower head on each line, some water would remain in the stem and the line below it. the property doesn't have a ton of slope so I'm picturing the line and stem at the lowest point being full, even if there is airspace further up the line.
 

68bucks

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Maybe you could rent a medium size compressor? Would only take a couple hours probably. Maybe borrow one? I'm with bud I would try the pancake compressor first.
 

bud16415

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Was thinking about this thread yesterday when i stuck my air nozzle into my connected 150' of 5/8, 3/4 hose and blew it out. it had 50' laying straight and 50' on each end coiled hanging down. after about a minute it started blowing air and after another minute went back to a full stream of water. I let it go about 5 minutes and it was all bone dry. I didn't screw on a fitting so I had a good amount of air blowing back at me. My compressor is a good sized 1HP.
 

IamAllThumbs

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I may have found a compressor to borrow. I will try the pancake, then the borrowed compressor on the same line to see if it flushes more.
 

sadavis80

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The only problem with the small pancakes is that they have no 'reserve'. The CFM is quite low and it won't be able to keep up. since the CFM is low, it can't keep up enough pressure to blow a line clear if it's more than about 10 feet long. If your valve box is accessible, I'd bet you can open up the input line and back drain the entire system with just gravity. Of course, I COULD be wrong and it might be expensive to find out.. but .. if it LOOKS like the valve box is at the lowest point of the system, then it SHOULD drain out .. although it might take a day or so. If you can open it up there, then just let everything drain out that will drain out and see how much water that is. If it seems to be enough... it probably is.

I would HOPE that a professionally installed system in COLD areas would make sure it had a low point drain for winter.
If there is any MFR or Installer info visible in the valve box, CALL them and ask.
YMMV,
Steve
 

IamAllThumbs

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The valve box is next to the house and basically at the highest point in the system.
I think the installers assumed it would be blown out every winter.
 

IamAllThumbs

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Ok a final update. The person that said they would let.me borrow their compressor changes their mind, but I got to see what they use, and it's one of the smallish "hotdog" compressors with like 3-5 CFM, not a major muti-thousands dollars model, and they say they have used it for over 10 years to blow their system, which is similar to mine (same neighbourhood, same builder).

So I put the pancake compressor for sales on the local social media and decided to buy something bigger. I wanted to get it done so ended up buying an oil-free Husky compressor from Home Depot. 8 gallon tank, up to 150 PSI for less than $200. Add in a hose and a couple fittings (of course the ones the home Depot employee told me I needed were wrong and I had to do a second trip), I'm at a out $250 with tax.

PXL_20221105_222422518.jpg

"They" tell you not to hook into the pressure vaccum breaker thingy, but my system has not other access point to insert pressured air. I checked the manifold and no way to hook into it either. I've watched the landscaping guy I've used for years hook up into the breaker thingy for years, so I figured I'd keep doing the same.

PXL_20221105_222831638.MP.jpg

As far as I can tell it worked like a charm. I let the tank get to fill pressure (150 PSI) then when the motor stopped, turned the zone on, got the air going at 50 PSI and except for one zone the compressor was able to pump till water stopped coming out. The largest and furthest zone required repressurizing the tank before blowing a second round.

Finished by draining the pipe that goes into my basement, left all the valves half opened and I think I'm good for the winter.

Now I gotta figure out where to store the new compressor...
 

bud16415

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Don't store the new toy find it a place in the garage and put it to work.
 

Whatmeworry

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A little extra if needed?
The small compressor hasplenty of pressure, just thestorage of that compressed air is not enough to let it blow long enough to clear the lines. The motor has to cycle too much, too often to keep the pressure up.
The CFM rating ishowquickly the small compressor can fill the tank. That is okay we let it run long enough to fill a much larger tank. Okay for retired guys but no good for a pro who wants to blow and go!

So to get alargertank,one doesn't have to get a bigger compressor, just add a second larger tank to be filled with the first one!
How about just one of the cheap tanks and lines and fittings to add the second when needing to blow out the lines?

Yes, extra wear and tear on the small compressor but many of us will never use one enough to wear it out if we take care of it. The idea is that we can have the advantage of a small compressor to do most of the things we need, while also being able to do the "big tank" when we need it!

Just don't try to cut the corner too short and use something not made for pressure! No old rusty junk that has been rejected as no longer safe! Those laws on propane tanks are there to keep us from killing people!
 

IamAllThumbs

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Yeah there is a YouTube video about a guy using a pancake compressor and an extra tank made from a propane tank. Since I didn't have any of the supplies and wasn't quite sure I trusted the safety aspect, I decided I could afford the new compressor.

If storage hadn't been a concern, I might have gotten the Harbour Freight 21 gallon model, and it was my backup plan if this Home Depot model didn't work.

I've already had interest on my ads to sell the pancake, so I'm ok with the overall price of this project, I'll get full return I'm my investment the next time I use it, and now I don't have to worry about scheduling someone else to do it.
 

bud16415

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Yeah there is a YouTube video about a guy using a pancake compressor and an extra tank made from a propane tank. Since I didn't have any of the supplies and wasn't quite sure I trusted the safety aspect, I decided I could afford the new compressor.

If storage hadn't been a concern, I might have gotten the Harbour Freight 21 gallon model, and it was my backup plan if this Home Depot model didn't work.

I've already had interest on my ads to sell the pancake, so I'm ok with the overall price of this project, I'll get full return I'm my investment the next time I use it, and now I don't have to worry about scheduling someone else to do it.
I know in today’s world jury rigging a solution is not widely accepted and the society is so litigious that even offering advice to do such is frowned upon.



I will say I have had a 20# propane bottle in use for 40 years as an air tank volume expander and portable air supply. I went to get the bottle filled years ago and was told it was out of date and had to be turned in. I said no way it is in perfect shape I will take it home and bought a new tank for the grill. In asking around on how to get my old tank re-certified I was told it would cost more than a new tank and they pressure test them to something like 500PSI. I said well if it can take 500 it surely could handle 100 off my air compressor and the guy said oh ya lots of people do that we even have a conversion fitting. Mine was empty and I never purged it with soap and water or removed the pressure blow off valve just added the adapter and a 8’ hose with quick connects. My compressor had 3 outlet ports so I plugged it into one of them and tossed it under the workbench leaving it plugged in all the time adding extra volume and capacity to the smaller compressor I had at the time. If I needed air away from the compressor I just grabbed the tank and went with it. I did spray paint “AIR” on the side one time.



After having this thing hooked on my compressor for 40 years a neighbor was in my garage a while back and saw it and ran out the door screaming at me that I was a crazy maniac and was going to blow us both up. I asked him if he wanted his mower blade sharpened for free or not.



Personally I trust that tank and the welds in it way more than I trust the $30 harbor freight pancake tank I have that was welded in China likely never tested and made from steel with dubious specs. I bought the harbor freight unit for the rare times when I want some air inside the house and don’t feel like bringing the dirty old propane tank in and out.



Here is the guy you might have watched. He went way past what I did and turned a 5 minute job into an all day project. Not that there is anything wrong with that as now that I’m retired I find myself doing the same thing.



I’m not advising anyone do this just it is what I have also done.



 
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