# I have 2 pumps which would you use (maybe I am missing something in CFM/PSI)



## Deadbolt Don (May 23, 2020)

I had the pleasure of my current 3 cyl single stage pump seize up on me last night. 
So I headed over to Princess auto (Temp. off work $$$ is everything at moment). I picked up a pump almost exactly like the one I had. It is what they use on their 60gal. High pressure unit.

Boasting 155 PSI and they mention 16.1 CFM @ 40 PSI/14.0 CFM @ 90 PSI.









4.7 HP Single-Stage Air Compressor Pump | Princess Auto


4.7 HP Single-Stage Air Compressor Pump




www.princessauto.com





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The second pump is also a 3 cyl single stage but the specs mention 18.5 CFM @ 135 PSI. <---- This one was on sale got the last one on the shelf!!









5 HP Single-Stage Air Compressor Pump | Princess Auto


5 HP Single-Stage Air Compressor Pump




www.princessauto.com





Am I wrong to assume the second unit is the better preforming pump? (for me at least) The rest of my specs are below.

My tank is a older Coleman powermate 60 gallon. The label says 135 max, (don't know if that is tank or original 1 cyl pump spec)? So is the 155 PSI pump even any use to me "safely"?

To be honest My motor is the weak link as it was under powered for the 4.7-5hp pumps. Also I found out I had wrong pulleys and was over revving the pump by about 300-400 rpm. I am surprised the motor didn't go first.
I have a 5hp motor on order so either of these pump should be happy as long as I speed match the pulleys. I am learning as I go. 
One stays on goes... You decide..!


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## iowagold (Jan 22, 2020)

well the big thing is what are you running??
large cfm is better for 2 da's or thunder guns...
but then again you have a small tank..
i would setup at least 100 gal tank and then use a larger dia line system for the shop.
that also helps as a reserve.
i like this system
*RapidAir 3/4in. MaxLine 100ft. Master Kit, Model# M7500*
RapidAir 3/4in. MaxLine 100ft. Master Kit, Model# M7500 | Northern Tool 
it will help store more air..
and they also have longer systems too or you can add on.
make sure you have large fittings at the tank or tanks...
if you are running super large impacts like over 3/4 drive then you need both high pressure and large cfm to keep up with the gun!
for a medium shop with a few guys working 100-200 cfm at 160 psi is nice with 400 gallons reserve.
and make sure you have regulators and gauge and at the outlets where it can be turned down at the point of use.
oh yea they make auto water drains now for the tanks!!
those are a cool add on for any shop!!
and make sure you have large air filters for the air inlets too.


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## iowagold (Jan 22, 2020)

i like this one way more bucks and you need a real tank
16.2 CFM @ 175 PSI. 
but you can turn down the main pressure regulator....
and change the tank to a real tank at a later date...
go with a tank rated at 300 psi or more at 100 gallons and add more tanks when money allows.








5 HP 2-Stage Air Compressor Pump | Princess Auto


5 HP 2-Stage Air Compressor Pump




www.princessauto.com





the higher the cfm the faster the recovery time when you run the tools...
and if you get a higher pressure pump and run it at lower pressure that is a good thing!!
it does not have to work as hard to get to 150 psi on a 175 psi rated pump!!


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## Deadbolt Don (May 23, 2020)

Thanks Iowagold, 
I seen the 2 stage pump there and thought about it for a minute. I am temp off work so I just can't make the plunge that deep. 
I ended up keeping the 18.5CFM @ 135 pump. But I realize my 3hp motor isn't going to like this pump, (even slowing it down is not going to cut it duty cycle wise). I have a 5hp 4 pole motor on order. So I have used any extra cash on the motor, and this should have been done long time ago.
I figured that the higher CFM is a better option since my "used" tank was originally labeled for 135 working pressure. I don't think I should go higher than than, so the higher PSI pump with less CFM really wouldn't benefit me much. 
As far as my need for air? 
I am slowly expanding my tools and skills. I have started to sandblast and powder coat some items. I realize that a 60 gallon isn't much for sandblasting, Hence why I am looking for a higher CFM pump.
I only have a small workshop about 16' long and its usually just me running air, but I have had 2 sanders running on a car once so it can happen. 
I made a rough sketch last night of my plumbing and finally getting around to installing my electric auto drains.
I have 1/2' lines run already so they will have to do for now. 
I do have a question based on the sketch below. Could I use a 3 or 4 way manifold and have all the drop legs drain into one (or 2) auto drain? My thought is this will "burp" any moisture from the main lines and the tank simultaneously? I don't have a real problem having a dedicated "dry air" auto drain as it is on the other end on the shop. 
I may need to set the duration of the purge a little longer, set to purge every 10 min. or so?









I have a MASSIVE auto propane tank that was thought to add into the system. My plan was to run it in a external covered area next to my shop. 
I don't know the "SAFE" pressure the tanks okay to, so I have been told 100 is usually okay. I think I could plumb a regulated line to the aux tank?
Or is there a better way? 
Am I wrong to assume I can pull sandblaster air from the "aux" tank. and the motor will kick in when the aux tank and main tank are at the 85-90 PSI start point?


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## stevon (Mar 5, 2019)

Don,

Using a 2 stage pump on a tank rated for single stage use is not a good idea. There should be at metal tag on the tank showing it's rating and WP air pressure should never be exceeded, especially if it is used tank. A compressor tank used and rated for single stage use should has a lower "WP" or rated working pressure. Either pump would work as long as the WP pressure is 150 or more. Just make sure your pressure safety release valve is the right range.







.The larger CFM pump is almost always the better choice, lower RPM and cooler running. Pump efficiency varies between manufactures slightly but physics never changes. If your 5HP motor only draws 15 amps then it is in reality a 3HP output motor. A motor that produces actual 5HP output at 230 volts will draw at least 19 amps or more listed on the motor as "full load amps". Using the propane tank may be OK, check the metal ASME tag on the tank and don't go past it's rating WP pressure.

Stephen


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## stevon (Mar 5, 2019)

Don,








I did a motor upgrade on my compressor too. got a great deal on a WEG 5HP for my Sanborn 2 stage. It draws 20.3 FL amps at 230 volt with a 5HP load on it.


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## Deadbolt Don (May 23, 2020)

The motor is here! 
What a beast!! To fat to fit right onto the mounting plate with out touching the pump cyl fins. Turns out it is a 184TC frame so I just ran to the metal shop picked up a 1/4" plate so I can make a sliding adapter plate since the new frame does not have slotted mounting holes. (Just realized as I was typing this, NO air for plasma cutter to blast the slots *%$#%..... well I filled the tank before I pulled motor but don't think will go to far)
Old motor is off I have a funny feeling I may be at this for a couple days, I don't have a hoist to lift that B*tch up there and off to mark and measure. Of coarse it is tucked into a corner and the PTO side is towards the walls. 
I never felt comfortable taking that tank any more than the sticker working pressure @ 135. So no worries there. I will check the metal tag,I think I seen one in near the back of tank..... 
Once I can get a good look at the propane tank I will see what is on it for tags/labels. That won't be for month or so since this opens up more work the wife will find for me to do (not compressor related).
The 3hp spinning it at 975-1000 RPM was so much quieter than when I over ran the last pump LOL. Can I expect this 1735 RPM to actually be quieter yet? I guess time will tell.


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## Deadbolt Don (May 23, 2020)

What do you guys think about plumbing all the drop leg drains to a manifold and auto drain the whole mess at once? See my air line drawing above.


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## stevon (Mar 5, 2019)

Don,

When I had shops in the past and even in some of my homes, went to the scrap yard and got 1" NTP pieces. bolted them on an angle and had traps with bleed valves to release captured water. There never was a drop in pressure using any tap along the line and the steel pipe cooled the air as it passed through. Just an idea

Stephen


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## stevon (Mar 5, 2019)

Don here is a cool calc for pulley and speed calculations:





Pulley Calculator. RPM, Belt Length, Speed, Animated Diagrams - Inch







www.blocklayer.com


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## Deadbolt Don (May 23, 2020)

Thanks Stephen,
The traps with bleed valves? Are these pressure release valves? Will they burp everytime the system hits a certain pressure? I have ball valves on them now. But I notice if I am working the compressor hard, (keeping in mind my incorrect previous setup) There was moisture in the traps often during use, and honestly I don't get to the traps as much as I should.
I have 2 Electric auto drains that we used in the old upholstery shop I worked in. They worked well to drain the impossible to get to tank drain. And now I have one plumbed to the tank drain here at home. During frequent use I set it to burp every 10 min for 1-2 seconds the pressure drop is almost nil. on the tank gauge, it has a test button that I can use to manually burp if needed. These can be set to be OFF for .5-45 min. and ON for .5 -10 seconds.
The 2nd drain was going to go on the air dryer drain since is also hard to get to.
I was hoping I could tie the drop legs into one or both of these. I noticed they have a 220v version. That would be nice to turn on compressor and have it power the auto drain as well, No forgetting to plug and unplug the drain power.
Automatic Drain Valve,G1/2 DN15 Automatic Electronic Timed Drain Valve for Air Compressor Condensate Management (AC110V): Amazon.ca: Home & Kitchen








If the bleed valve you mentioned does it with pressure that may work as well. Do you have a link for something similar?

I have had that block layer site up on both the computer and phone for the last week.... Great info there! This is how I realized that I was over running the dead pump.


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## stevon (Mar 5, 2019)

Don,
No these only operate if something goes wrong and electric motor keeps pumping beyond a safe air pressure for the tank:








High Pressure Relief Valve | Male NPT 1/4 in. @ 150 PSI - Brass / ASME


The ST25-A0### line of pressure relief saftey valve are brass constructed, have a threaded male NPT inlet connection with a stainless steel pull ring for manual pressure relief.




www.glaciertanks.com


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## stevon (Mar 5, 2019)

Don,
Draining the condensation automatically is only needed in a factory or 24/7 body shop. Manual draining once a week is more than enough. The 18 foot 1" pipes I got from the bone yard was to separate condensation in the air so it wouldn't get through my spray gun and ruin my paint jobs. It worked quite well along with a filter. The air tools required oil added to the fittings once in a while and didn't seem to mind water and air passing through them. I cut and threaded pipe as needed and added a tee facing up. The pipe was at an angle on the wall and collected condensate ran along the bottom to the end and collected on the drop pipe. putting drops at every fitting is overkill in my opinion, one drop and drain valve on each wall I ran the pipes was adequate for me.


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## chavenor (Nov 18, 2020)

stevon said:


> View attachment 7853
> Don,
> Draining the condensation automatically is only needed in a factory or 24/7 body shop. Manual draining once a week is more than enough. The 18 foot 1" pipes I got from the bone yard was to separate condensation in the air so it wouldn't get through my spray gun and ruin my paint jobs. It worked quite well along with a filter. The air tools required oil added to the fittings once in a while and didn't seem to mind water and air passing through them. I cut and threaded pipe as needed and added a tee facing up. The pipe was at an angle on the wall and collected condensate ran along the bottom to the end and collected on the drop pipe. putting drops at every fitting is overkill in my opinion, one drop and drain valve on each wall I ran the pipes was adequate for me.


I've got three compressors I'm putting together they are in the basement under the garage. So everything would be flowing back to the compressors is that ok? My pips have to go up?


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## stevon (Mar 5, 2019)

chavenor

I would only use one line going up 1" and in effect a manifold to collect and a manifold to distribute

Stephen











chavenor said:


> I've got three compressors I'm putting together they are in the basement under the garage. So everything would be flowing back to the compressors is that ok? My pips have to go up?


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