expired Posted by maverick2007 • Nov 4, 2020
Nov 4, 2020 4:17 PM
Item 1 of 1
expired Posted by maverick2007 • Nov 4, 2020
Nov 4, 2020 4:17 PM
Porter Cable 24-Gallon Portable Air Compressor
+ Free Shipping$160
Tractor Supply Co
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Here's [northerntool.com] an example of a $1K compressor that can supposedly deliver 18 CFM at 90 PSI continuously.
This [harborfreight.com] Harbor Freight sander claims to require an average of 4 CFM at 90 PSI. The term average is a dead giveaway they are using a duty cycle, but they don't tell you what the duty cycle is. If they're using a 25% duty cycle, it would require 16 CFM to operate continuously, and the above 18-CFM compressor should barely be able to run it continuously. This [harborfreight.com] Harbor Freight sander claims to require an average of 2.5 CFM, but they also tell you it requires 16.9 SCFM. That seems to imply Harbor Freight is using a 15% duty cycle for the average CFM rating.
Northern Tool says this sander [northerntool.com] requires 1.6 CFM, but they don't tell you the duty cycle. Northern Tool says duty cycles are often 25% [northerntool.com] and recommends you multiply CFM requirements listed on their chart by 4 for continuous use. Does the 25% duty cycle rating apply to their 1.6-CFM sander? Who knows.
I would try to find out the continuous CFM requirement for the sander you want to use and then find an air compressor with a 100% duty cycle that exceeds that requirement by a reasonable margin. If you aren't happy with the cost of such an air compressor, maybe you can find a sander with a lower CFM requirement or compromise a bit on the duty cycle.
When you say, "air dryer," I am thinking after a water separator, such as a desiccant drier as the most basic on up to the refrigerated driers that will go deep into your pockets. If you are just wanting a water separator, they start at $10 and go up.... Start with Amazon or yes, even HF and work your way up. The cheapest ones are all going to be in China.
I've done what others mentioned here....blow them out zone by zone. Let the compressor refill again and blow out same zone again until mist is all but gone from all the heads in the zone.
I've done it this way....waiting for mist as that's the way the sprinkler company's do it. They have really big compressors that put out a lot of cfms. There's little waiting for them so they don't care.
Believe it's all overkill now. Neighbor who is a contractor never blows out his system and he's never had an issue. He simply opens a valve he installed by the lowest head in the zone. This way the water has somewhere to go as it expands rather than cracking the pipe or damage the head.
Seems to make sense. So as long as you get a decent amount of water out it should be totally fine. Your only issue is if the water expands enough to cause issues. Water expands roughly 10% when it freezes. So should be fine just cycling thru one time per zone, assuming that gets more than 10% of the water out of your zone.
I've used high psi—-like 110. The only issue I've ever had is getting a split in the supply line before the valve control box. I use a remote to electronically open the zone rather than bend and open the valve manually. Unfortunately, have had some loose wires and sometimes a zone wouldn't open. I didn't know and sent thru a lot of psi. That COULD be why the supply line has cracked. Could also be too much psi for it to handle. Wires all have new connections and I'm going to lower the psi this year. Just not sure how low to make it.
I see.
When unused do keep unused air in the tank or empty it to avoid rust buildup????
I attached a ball valve on the bottom of the tank to blow out any condensation. I also live in AZ so it doesn't build up much to begin with.
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Any idea? Suggestions? I don't have a garage right now so this is as large as I think I can go.
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