Anyone know much about Air Compressors and blowing out sprinkler systems? I have 5 houses that I am paying $65 a pop to blow out each year and I am finally ready to buy my own air compressor and save the money.
From my limited research, it appears that the PSI needed is only about 60 to 90 max. If I got a higher PSI rated unit, do they have the ability be toned down to a lower setting? Next it appears that the bigger the Gallon tank, the better? I have seen some tank in the $400 range that are 28 gallons, but is that over kill? What size should I target for residential uses?
Finally, I wouldn't mind getting one that could work for both blowing out sprinklers and hooking up a nail gun when needed. Also, I am noticing that stores like Home Depot & Lowes include a few air compressors in their Black Friday deals. I wonder if I might be able to snag a good deal?
I worked with/sold/designed compressed gas systems for 8-9 years. What do you need to know?
What is the typical ID of the sprinkler system?
What is the length of the system?
What is the pressure required to actually push the residue out of the system?
P1 x V1 = P2 x V2
P1 = Pressure of the tank (i.e. max pressure of the compressor)
V1 = Volume of tank
P2 = Pressure required to push out residue
V2 = pi x Length of Pipe X (ID / 2)^2
EDIT: Make sure your volumes have the same unit of measurement.
You will want to solve for V1.
That V1 will give you the total amount of compressed air you would want to store if you wanted to do the whole job without a compressor. (Assuming a fully compressed line does the job? You might need run time to keep the stuff pushing.)
Compressors are rated in Horepower and should give you a CFM rating. If you have trouble getting a CFM rating for your compressor, multiply the HP by 4 and it'll give you a ballpark number. Compressors are also rated with a maximum PSI. They also have an operating range. While the max pressure may be 125 psig, it might not be able to maintain 125PSIG at full blow, so keep that in mind. I usually would give it a 15psig range on it, unless you buy a compressor with controls to keep the pressure up. But then you run your motor a lot.
Once you have your CFM rating, you will be able to figure out how fast you can generate the volume of air necessary to maintain pressure and flow throughout the system.
The real real world concerns you'll come up against is leak rate. How fast is the air leaking out of the system at the end points/joints.
What you'll find at Home Depot are simple 1-5 gallon pancake compressors that might not have enough oomf for what you need to do.