Triad Roof Cleaners LLC Report post Posted January 30, 2015 I'm looking for a reasonably priced air compressor to get full potential out of a 1/2 pump. Most specs I see seem to indicate you will need a minimum 9 HP unit to get the desired CFM. Northern Tool has a Compressor they claim delivers 13.7 CFM @ 90 PSI but if you look at the specs the GX160 Honda it's equip with is rated at 4.8 HP. I like the fact that it has a 20 gal single tank for reserve but do you guys think this compressor will get the full potential out of a 1/2 pump. I tried to insert the URL so you could take a look at it but it said I was not allowed to upload that type file Share this post Link to post Share on other sites
Shingle Brite Report post Posted January 31, 2015 I'm looking for a reasonably priced air compressor to get full potential out of a 1/2 pump. Most specs I see seem to indicate you will need a minimum 9 HP unit to get the desired CFM. Northern Tool has a Compressor they claim delivers 13.7 CFM @ 90 PSI but if you look at the specs the GX160 Honda it's equip with is rated at 4.8 HP. I like the fact that it has a 20 gal single tank for reserve but do you guys think this compressor will get the full potential out of a 1/2 pump. I tried to insert the URL so you could take a look at it but it said I was not allowed to upload that type file I am no expert but I would study the unit below pretty hard before I pulled the trigger on the one from Northern Tool. http://www.eatoncompressor.com/catalog/item/537473/283705.htm Share this post Link to post Share on other sites
ReNew Roof & Exterior cleaning Report post Posted January 31, 2015 If you are going to spend 1k on a compressor, check this one out. It will leave you room for upgrading to a larger roof cleaning pump if you ever wanted to. http://www.harborfreight.com/30-gal-420cc-truck-bed-air-compressor-epa-iii-69784.html Share this post Link to post Share on other sites
PeakOfPerfection Report post Posted January 31, 2015 If you don't have the room for the big HF compressor, but you want something that will max out the 1/2" pump and run a bigger pump up the line, take a look at this one... http://www.eatoncompressor.com/catalog/item/537473/191127.htm Slightly larger tank. Eaton is also fairly honest with their CFM ratings. Many compressors rate the theoretical CFM of the pump which is simply a measure of the cylinder size but NOT what the compressor will actually deliver. Eaton will tell you, as an example, one compressor might have a 20 CFM *displacement* pump but with that engine you will only get 14 CFM in the real world. The cheaper, Chinese built compressors will simply say it is a 20 CFM compressor. I've had crap luck with Northern Tool gear and guys in the power wash community avoid their stuff like the plague. Share this post Link to post Share on other sites
Triad Roof Cleaners LLC Report post Posted January 31, 2015 Thanks for the feedback Clayton, Gene and Peak. Your info gives me choices I hadn't considered in that price range for what appears to be superior to the Northern Tool unit. Share this post Link to post Share on other sites
garyw Report post Posted January 31, 2015 Take a look at this. Good buy for the price .http://www.govdeals.com/index.cfm?fa=Main.Item&itemid=1926&acctid=658 Share this post Link to post Share on other sites
Shingle Brite Report post Posted January 31, 2015 If you don't have the room for the big HF compressor, but you want something that will max out the 1/2" pump and run a bigger pump up the line, take a look at this one...http://www.eatoncompressor.com/catalog/item/537473/191127.htm Slightly larger tank. Eaton is also fairly honest with their CFM ratings. Many compressors rate the theoretical CFM of the pump which is simply a measure of the cylinder size but NOT what the compressor will actually deliver. Eaton will tell you, as an example, one compressor might have a 20 CFM *displacement* pump but with that engine you will only get 14 CFM in the real world. The cheaper, Chinese built compressors will simply say it is a 20 CFM compressor. I've had crap luck with Northern Tool gear and guys in the power wash community avoid their stuff like the plague. Share this post Link to post Share on other sites
Shingle Brite Report post Posted January 31, 2015 If that compressor will max out a 1/2" pump what kind of performance should I expect with my 1" pump? Will my pump perform the same, better or worse than the smaller one using the same compressor? Share this post Link to post Share on other sites
Shingle Brite Report post Posted January 31, 2015 So far as pumps and such is the following correct? I am assuming different pump size and hose sizes are reasonably similar and within the norm for roof cleaning. 1. 2 pumps of varying sizes will perform similarly with the same cfm but the smaller pump will work harder and more often. 2. A bigger hose will allow any pump to provide more flow due to less surface resistance. 3. Tank size matters on compressor because a smaller tank will lose pressure quicker and force the compressor to work harder. Also with too small a tank the compressor may not be able to maintain desired tank pressure or cfm. 4. Hp matters on a compressor because it relates to how fast the compressor can recover when under demand. 5. Cfm matters because more means more flow at more distance. Share this post Link to post Share on other sites
garyw Report post Posted January 31, 2015 correct on all points. Share this post Link to post Share on other sites
PeakOfPerfection Report post Posted January 31, 2015 So far as pumps and such is the following correct? I am assuming different pump size and hose sizes are reasonably similar and within the norm for roof cleaning. distance. 1. 2 pumps of varying sizes will perform similarly with the same cfm but the smaller pump will work harder and more often.pp Close. A bigger pump will pump more with the same CFM due to the increase in volumetric efficiency, assuming the bigger pump is getting enough air to move the diaphragms. At a point in size, the pump is large enough there isn't enough air to physically force that much fluid in the chamber thru a stroke....say a 2" pump vs a 1/2" pump on a 10 CFM compressor. 2. A bigger hose will allow any pump to provide more flow due to less surface resistance. Correct, but with limitations. Makes no sense to put 3/4" hose on a 3/8" pump, nor try to use 2" hose on a 2" pump due to the weight of the fluid. You are essentially driving a vertical column of water so at some point the weight of that column will overcome the ability of the user to safely handle it on a roof or ladder. The weight cutoff for safe handling seems to be around 1". You have to balance efficiency with safety and the ability to handle the hose at heights. 1/2" hose for a 3/8" pump. 5/8" hose for a 1/2" pump. And 3/4" hose is the ideal size for a 3/4" or larger pump. 3. Tank size matters on compressor because a smaller tank will lose pressure quicker and force the compressor to work harder. Also with too small a tank the compressor may not be able to maintain desired tank pressure or CFM. Kind of. The tank acts as a buffer against demand. A small tank with a massive compressor capable of a ton of free flow air won't matter. Free flow is the rating of the pump to deliver air without a tank reserve. A 70 CFM VMAC under hood compressor with a 5 gal tank or a tankless air screw compressor like a Twister Diablo don't need big...or any tanks. With the smaller compressors, you are correct as they have small free flow ratings and thus depend on the tank for a reserve of air against demand. 4. Hp matters on a compressor because it relates to how fast the compressor can recover when under demand. Partially. Larger motors deliver more torque. Torque is the ability to drive the pump efficiently under load. Remember, you are compressing a gas and that takes a lot of force. Close the valve on a bicycle tire pump and then try to push it down, it takes a lot of force to squeeze the air. Same pump, two different motors. The higher horsepower motor with higher torque will keep the pump moving at an optimal speed to continue to deliver air at the max capability of the pump under load. A smaller, lower torque motor will struggle against the demand, particularly at higher PSI ranges. Wears the motor out faster and lowers the output of the pump since it will strain against the load and slow. This is why a smaller 10 HP Diesel engine is the equivalent of a 14-15 HP gas engine in compressor use and why electric horsepower tastings are so much lower in high CFM compressors....far more torque. 5. CFM matters because more means more flow at more distance. Think about how an air diaphragm pump works. As the piston....or in this case diaphragm, moves to the bottom of the stroke, the air valve opens and lets a volume of air into the chamber behind the diaphragm. This is what drives the piston up (or out) and forces the fluid on the other side of the piston to be compressed and exit the valve into the output manifold. The greater the volume of air that moves into the chamber as the air valve is open, the stronger the diaphragm will push against the fluid. That higher volume is where CFM comes into play. this is why a 1" pump will move double the fluid volume at 40 CFM vs 20 CFM at the same pressure. 1 JetBlueRacer reacted to this Share this post Link to post Share on other sites
Beacon Roof Cleaning Report post Posted February 1, 2015 If you are going to spend 1k on a compressor, check this one out. It will leave you room for upgrading to a larger roof cleaning pump if you ever wanted to. http://www.harborfreight.com/30-gal-420cc-truck-bed-air-compressor-epa-iii-69784.html We have this one and its awesome!!! 2 Apple Roof Cleaning (813) 655-8777 and ReNew Roof & Exterior cleaning reacted to this Share this post Link to post Share on other sites
Bryce Canfield Report post Posted April 10, 2015 Off topic but I love your website. I build sites on the side this is simple,clean,bright and user friend.. I dig it!... Nice job to your designers.. Bryce We have this one and its awesome!!! Share this post Link to post Share on other sites
Apple Roof Cleaning (813) 655-8777 Report post Posted April 12, 2015 We have this one and its awesome!!!We have this one too, and I agree! Share this post Link to post Share on other sites
