Harbor freight air dryer.

[joeyjudge]

Hello, I have a HF air dryer that was installed on a 5hp 60 gallon compressor that is strictly used for my booth. Installed in 2018 and other than replacing the drain it has been great.
Has anyone ever used it on a 7.5 HP with a 80 gallon tank?

Just not sure how it would perform with the larger compressor.

Located in Tampa....always hot and humid.

Thank you.

 

[MJM]

I don't see why it wouldn't work. I know SPI member DHutton and Shine have a HF air dryer, just not sure of their compressor capacity. I also have a HF air dyer that is used for my 80 gallon 175 psi 5hp continuous duty air compressor. I've had no problems with my air dryer. As you are probably aware, HF states the air dryer should have a regulator installed between the air compressor and air dryer. This is done to maintain HF's recommended 145psi inlet pressure to the air dryer from the compressor. I have followed that recommendation but, I have read on HF's reviews concerning the air dryer that several people have ran the air dryer at 175 psi inlet pressure with no issues. I do believe that's true because the units are calibrated to handle 200 to 220 psi inlet pressure, at least mine was, I checked.

Here's my set up......

 

[MP&C]

One thing I did when installing my dryer was to remove the copper line going from the compressor head to the tank and route the air line through my Pneumatech refrigerant dryer. Air gets dried before it hits the tank. Also added cutoff valves and a bypass at the dryer for contingency of a dryer failure.

 

[Treeslayer]

I don't see why it wouldn't work. I know SPI member DHutton and Shine have a HF air dryer, just not sure of their compressor capacity. I also have a HF air dyer that is used for my 80 gallon 175 psi 5hp continuous duty air compressor. I've had no problems with my air dryer. As you are probably aware, HF states the air dryer should have a regulator installed between the air compressor and air dryer. This is done to maintain HF's recommended 145psi inlet pressure to the air dryer from the compressor. I have followed that recommendation but, I have read on HF's reviews concerning the air dryer that several people have ran the air dryer at 175 psi inlet pressure with no issues. I do believe that's true because the units are calibrated to handle 200 to 220 psi inlet pressure, at least mine was, I checked.

Here's my set up......
View attachment 27630

i see your cooler valves are all open. i was wondering if that may be a good idea when not in use to dry out the system?

 

[MJM]

One thing I did when installing my dryer was to remove the copper line going from the compressor head to the tank and route the air line through my Pneumatech refrigerant dryer. Air gets dried before it hits the tank. Also added cutoff valves and a bypass at the dryer for contingency of a dryer failure.

View attachment 27631

View attachment 27632

For my own edification on your set-up. How are the lines hooked up to the air dryer from the compressor?

I'm assuming from compressor cylinder head to "inlet" of air dryer, then "outlet" of air dryer to compressor tank?

Is this correct?

 

[MJM]

i see your cooler valves are all open. i was wondering if that may be a good idea when not in use to dry out the system?

I can't see it hurting having them open to dry out any moisture that might be in there. That picture was taken the day I finished installing the air dryer. I had opened the valves a few days before installing the air dryer so the copper lines had some time to dry out any moisture.

 

[MP&C]

For my own edification on your set-up. How are the lines hooked up to the air dryer from the compressor?

I'm assuming from compressor cylinder head to "inlet" of air dryer, then "outlet" of air dryer to compressor tank?

Is this correct?

Yes, exactly. When I initially installed it, I had countless internet experts tell me the heat from the compressor head was too hot for the input of the Pneumatech dryer. 20 years and counting, knock on wood.

 

[MJM]

Yes, exactly. When I initially installed it, I had countless internet experts tell me the heat from the compressor head was too hot for the input of the Pneumatech dryer. 20 years and counting, knock on wood.

That heat concern would not have occurred to me. Good to know it hasn't caused you any issues.

I recently installed a mini fan blowing air at the cylinderhead. That alone has reduced stored heat within the cylinderhead which has to be helping some with moisture.

 

[Treeslayer]

how hot is hot? you have what? three or four feet at least? i would think it would cool quite a bit in that distance. on a truck compressor, normally the braided line coming off that is only three feet. it gets pretty hot but after that you can put your hand on it.

 

[64avanti]

I don't know if the Harbor Freight dryer will work on a larger compressor. I recently added a dryer to mine, and the HF dryer wasn't rated for the 20 CFM that my compressor puts out. I didn't want to waste the time and money installing an undersized dryer, so I bought a larger one.

I have no regrets, as it works perfectly. I used to have to drain my regulators at least once a day, and I haven't had to drain a single one since. I don't know if this would be true with the HF dryer.

P.S. it's been 2 months since I added the dryer. It was a hot and humid summer here and I still haven't drained a separator.

 

[MP&C]

how hot is hot? you have what? three or four feet at least? i would think it would cool quite a bit in that distance. on a truck compressor, normally the braided line coming off that is only three feet. it gets pretty hot but after that you can put your hand on it.

The black pipe out of the compressor head gets hot enough you can’t keep your hand on it where it crosses there in front of the tank. The one out of the dryer going into the tank is colder than ambient room temp.

 

[Jim C]

there are hot air dryers. they are no different but designed to handle much hotter input temps and still bring the dew point down under 40deg f. alot of the mfg's have all their dryers in either std or hot versions.

for the hf dryer handling a 7.5...well hp and tanks size dont matter. its how hard you are working the machine and what you get that input temp up to. even a 5hp which its rated for could overpower it if its 100 deg out and the compressor is going to have to run at 100% duty cycle. for a 7.5hp compressor that is kicking on and off once every 3 min your going to be fine. if you blasting with it then no way

 

[joeyjudge]

thank you for your responses!

 

[Whitesnake]

there are hot air dryers. they are no different but designed to handle much hotter input temps and still bring the dew point down under 40deg f. alot of the mfg's have all their dryers in either std or hot versions.

for the hf dryer handling a 7.5...well hp and tanks size dont matter. its how hard you are working the machine and what you get that input temp up to. even a 5hp which its rated for could overpower it if its 100 deg out and the compressor is going to have to run at 100% duty cycle. for a 7.5hp compressor that is kicking on and off once every 3 min your going to be fine. if you blasting with it then no way

I agree with all of this. Something to possibly consider is adding a cooler in line between your pump and tank. I have a trans cooler plumbed in between with soft copper and a moisture trap with auto drain before it goes in the tank. That alone cools the air going into the tank significantly.

 

[Jim C]

Yes, quincy and some other better compressors have an option for something like this right from the factory.

 

[D.A.T.]

there are hot air dryers. they are no different but designed to handle much hotter input temps and still bring the dew point down under 40deg f. alot of the mfg's have all their dryers in either std or hot versions.

for the hf dryer handling a 7.5...well hp and tanks size dont matter. its how hard you are working the machine and what you get that input temp up to. even a 5hp which its rated for could overpower it if its 100 deg out and the compressor is going to have to run at 100% duty cycle. for a 7.5hp compressor that is kicking on and off once every 3 min your going to be fine. if you blasting with it then no way

Tank size absolutely does matter--it is the foundation and corner stone of what you want to achieve in eventually getting the least moisture in your delivered air in the first phase of water drop out in using compressed air. By condensing out the bulk of the moisture in the storage tank--you will avoid one loss of CFM as in distribution piping runs and choking down in dryer coils and their restrictions after this first drop out. Unless you put an anemometer at the end of your air hose--you won't know what you are pulling out of your tank in CFM at some set pressure on the wall and more important where to set at the tank tap regulator pressure. CFM output and pressure loss between two piping points--inlet and outlet are directly influenced by piping ID, number of directional changes and returns and length of piping.


The smaller the diameter of the tank and shorter the shell--the less the weight of the tank and greater the problem. All use 2:1 semi-ellipsoidal heads for end caps now and the common 24" OD 80 gallon tanks barely weight 325 lbs. Most barely have 3/16" thick shells and heads. Very meager for heat dissipation, but fine for a 25 year life span or so of internal pressure containment at 175psi with a 350% safety factor built in. I hydrotested a pair of 400 gallon 42" diameter tanks this this morning that weigh 3300 lbs each. I rated them for 250psi at 400F. A customer in Texas will use these in a critical application and use minimal delivery piping and one dryer at the end of the piping run right before the load. They have 900% more heat absorbing mass than a typical commodity tank to condense out the moisture first by making a massive heat sink. I purposely designed them this way for that function. For people at home or a light business--the best is to add in a second commodity tank another 80 or better a 120 gallon on in series to that on your compressor to get the air storage up and the time in the tank up to help condense out in another storage phase.

Compressor motor size and CFM output only refeed/replenish the energy withdrawal from the tank and are secondary to getting rid of heat since the compression ratio is fixed on piston type pumps. A temperature gain of 70-100F is not a bad estimate for piston compressor I checked the 45hp rotary screw this morning and the air draw in is 60F and the output is 147F. Whether it is 20F or 106F outside--that compressor gives about the same gain--+85F or so.

My little 4 stage HVLP turbine is consistently +80F increase in temp no matter what the air intake temp is. So that is pretty consistent with that attained by a rotary screw compressor I use. The difference there is the output is 62-70CFM @ 6pis and It took one hell of a lot more heat sink that I thought to get it back to ambient coming out the gun. I lost 26% of my flow in CFM in just 20Ft of 1" copper tube through a mass of 45 gallons of 60F water. I got it to spray SPI Production like a dream. Not enough moxey to do high solids on that one alone. A touch of nitrogen assist work well out of one of my old plasma cylinders.

Any dryer with aluminum tube and brazed fins (the cheapies), whether refrigerated or not, will only be another 15-30ft of length of heat transfer potential with a fairly fast airflow through it. The less the inlet temperature going in the better the efficiency. Most of the non-refrigerated ones work marginally as the last drop out. All will do something--higher CFM flows and closer to the compressor is not ideal for a rated one of lesser CFMs' and the idea is to get to some artificially low dew point. You need to know by measurement what is coming out the end of your air-hose in CFM to size a dryer size for being optimum--not your compressor pump output to size anything.

Inner-coolers are a poor idea. The factory Ingersol Rand on a 80 gallon 7.5 hp one I use failed after 10 years from cycling and fatigue between the secondary outlet and the tank. 8 week wait time during COVID and 1/3 the cost of the compressor. Aluminum fin transmission coolers for liquids are really susceptible for tubing and brazing joint failure due to fatigue in a compressed air pumps turning on and off and their expansion issues in warm weather and how they might be mounted.

 

[Treeslayer]

DAT, my old tank came from an OLD service station, i dont even know how old it is but is very heavy. is this good or bad?
it does not leak, thats about as much as i know other than its older than me. new pump, motor, check valves and all that good stuff of course.

 

[Jim C]

while all that may be true, what i am getting at is it comes down to the heat load on the refer dryer, not the size of the compressor. a dryer can only get rid of "X" amt of heat for its size. makes no difference if its 2hp or 100. its more about how the compressor will be used. of course most of us at some point use our compressor at 100%. if your dryer is not rated to handle that cfm at whatever temp the inlet air is then dew point will go up. if the compressor never goes beyond 25% duty cycle even though the compressor is say 20 hp then the same dryer rated for a 5hp may work. with all that said, why purchase a dryer not rated for 100% of your compressors output? dont let the dryer be the limiting factor of your air system. imo it should be oversized just a little.

 

[Whitesnake]

Tank size absolutely does matter--it is the foundation and corner stone of what you want to achieve in eventually getting the least moisture in your delivered air in the first phase of water drop out in using compressed air. By condensing out the bulk of the moisture in the storage tank--you will avoid one loss of CFM as in distribution piping runs and choking down in dryer coils and their restrictions after this first drop out. Unless you put an anemometer at the end of your air hose--you won't know what you are pulling out of your tank in CFM at some set pressure on the wall and more important where to set at the tank tap regulator pressure. CFM output and pressure loss between two piping points--inlet and outlet are directly influenced by piping ID, number of directional changes and returns and length of piping.


The smaller the diameter of the tank and shorter the shell--the less the weight of the tank and greater the problem. All use 2:1 semi-ellipsoidal heads for end caps now and the common 24" OD 80 gallon tanks barely weight 325 lbs. Most barely have 3/16" thick shells and heads. Very meager for heat dissipation, but fine for a 25 year life span or so of internal pressure containment at 175psi with a 350% safety factor built in. I hydrotested a pair of 400 gallon 42" diameter tanks this this morning that weigh 3300 lbs each. I rated them for 250psi at 400F. A customer in Texas will use these in a critical application and use minimal delivery piping and one dryer at the end of the piping run right before the load. They have 900% more heat absorbing mass than a typical commodity tank to condense out the moisture first by making a massive heat sink. I purposely designed them this way for that function. For people at home or a light business--the best is to add in a second commodity tank another 80 or better a 120 gallon on in series to that on your compressor to get the air storage up and the time in the tank up to help condense out in another storage phase.

Compressor motor size and CFM output only refeed/replenish the energy withdrawal from the tank and are secondary to getting rid of heat since the compression ratio is fixed on piston type pumps. A temperature gain of 70-100F is not a bad estimate for piston compressor I checked the 45hp rotary screw this morning and the air draw in is 60F and the output is 147F. Whether it is 20F or 106F outside--that compressor gives about the same gain--+85F or so.

My little 4 stage HVLP turbine is consistently +80F increase in temp no matter what the air intake temp is. So that is pretty consistent with that attained by a rotary screw compressor I use. The difference there is the output is 62-70CFM @ 6pis and It took one hell of a lot more heat sink that I thought to get it back to ambient coming out the gun. I lost 26% of my flow in CFM in just 20Ft of 1" copper tube through a mass of 45 gallons of 60F water. I got it to spray SPI Production like a dream. Not enough moxey to do high solids on that one alone. A touch of nitrogen assist work well out of one of my old plasma cylinders.

Any dryer with aluminum tube and brazed fins (the cheapies), whether refrigerated or not, will only be another 15-30ft of length of heat transfer potential with a fairly fast airflow through it. The less the inlet temperature going in the better the efficiency. Most of the non-refrigerated ones work marginally as the last drop out. All will do something--higher CFM flows and closer to the compressor is not ideal for a rated one of lesser CFMs' and the idea is to get to some artificially low dew point. You need to know by measurement what is coming out the end of your air-hose in CFM to size a dryer size for being optimum--not your compressor pump output to size anything.

Inner-coolers are a poor idea. The factory Ingersol Rand on a 80 gallon 7.5 hp one I use failed after 10 years from cycling and fatigue between the secondary outlet and the tank. 8 week wait time during COVID and 1/3 the cost of the compressor. Aluminum fin transmission coolers for liquids are really susceptible for tubing and brazing joint failure due to fatigue in a compressed air pumps turning on and off and their expansion issues in warm weather and how they might be mounted.

Well…how about an ac condenser then. They see high pressures. Nothing is bullet proof. Everything has a life. Nothing last forever. Even the space shuttle blows up.

 

[D.A.T.]

DAT, my old tank came from an OLD service station, i dont even know how old it is but is very heavy. is this good or bad?
it does not leak, thats about as much as i know other than its older than me. new pump, motor, check valves and all that good stuff of course.

Likely the bulk of the weight on your old service station compressor was not the tank but the industrial pump itself and a very well made 5-7.5 single phase motor loaded with copper windings and a continuous duty cycle. Many were vertical tanks of 80-120 gallons with slow speed pumps that worked well for the pneumatic operated cylinders in-ground car lifts of the day.

All prepackaged air compressors (common names) sold use commodity tanks and they are thin to keep their costs lower. For the 33 years i have been involved in such things--all have an additional 1/16" of provided metal for internal corrosion allowance. I would encourage you to find someone to either ultrasonically test it to see what remains after all these years--some are like brand new--others are tissue paper thin--seen dozens both ways. Ingersoll Rand buries it in their owner's manuals to hydrotest (pressurized water test) every year. You can disconnect everything isolate the tank and do a 30 minute hydrotest @70F to what it is rated for in pressure on the nameplate.

Leaks are that--the danger is rupture down the long way of the shell cylinder when it is too thin and on a cold morning. An 80 gallon tank at 175 psi is about 2.5 sticks of 1"x 12" Dyno-Nobel dynamite when it ruptures. Farmers used to have a hard time believing a typical small 40 gallon air tank at 100 psi was about 1 stick of dynamite at rupture and one of the Ag publications a awhile back helped get that word out. More than a few have been obliterated with ruptures in the back of their farm service trucks in cold climates especially. Unless you have insurance policy for boiler and pressure vessel casualty--you are uninsured with respect to rupture and its consequences at your home/business.

I do all that--if I lived closer and was retired, I would come over and do it for you gladly.