Wednesday, August 30, 2017

10 Worst Things You Can Do To Your Air Compressor

By Peter Rhoten

Over the 35 plus years in the business I’ve seen a number of bizarre things that are done to a compressor and the components in the system. People often wonder why their system does not run well, they have high power costs, or have numerous OSHA issues. I've previously shared this list awhile back in my eNewsletter and received a lot of feedback, so, I decided to post it again via blog.

Here is my "Worst Things You Can Do To Your Air Compressor" Top Ten
Worst Offenders List:

#10 - Duct tape should not really be used to repair leaking air tank

#9 - Shipping pallets are not really meant to be the permanent base for your new compressor

#8 - Oil changes are not an every 5-year event

#7 - PVC schedule 40/80 piping should really not be used for compressed air - stand back here it comes

#6 - Just because the air filter is dirty you really should not leave it off

#5 - Using an old baseboard radiator for aftercooler is not a great idea

#4 - If your air tank still has rivets holding it together it's probably a good idea not to use it anymore

#3 - It's not really okay to wire the safety valve together because it is noisy and annoying

#2 - No problem just piping all the oily water down the outside of the building - nobody will notice just because it's near the entrance

#1 - You really shouldn't let employees sleep inside the 400 HP compressor cabinet just because it's warm - really happened

So that's my short recap of things that I saw that I didn't believe. Many of them are still occurring, not as much in the US, but in other parts of the world.

I would love to hear about any unusual air system observations that you may. Of course, all information will remain anonymous.

Be aware and be safe. Visit our Compressor Service Page.

If you need some help with your system, call Frank at 508-351-1817 or email:

Friday, July 21, 2017

Oil and Water Are Not Your Friend

Is There a Rainstorm
Inside Your Compressor?
Be Legal, Be Green

Water is unavoidable in a compressed air system. Think about it: When you are compressing seven cubic feet of atmospheric air into one cubic foot inside the compressor, this cubic foot of air now contains seven times as much moisture as what existed in the atmosphere. The cubic foot of compressed air in the system is at 100 percent humidity at least 190° Fahrenheit or more, so it literally rains anytime the temperature goes below 190° F in the separators/filters/dryer. The key is how to dispose of it legally and to be conscious of our environment.

In winter conditions, a 200 CFM compressor with 70°F inlet air with 50% relative humidity makes ¾ of a gallon of condensate per hour, or 60 gallons per week in a 2-shift operation. In summer conditions, a 200 CFM compressor with 85°F inlet air with 80% relative humidity makes two gallons of condensate per hour, or 160 gallons per week in a 2-shift operation. (
Calculate how much condensate your systems)

Water condenses out of the airstream in the system, as it flows through the wet tank, pre-filter, refrigerated dryer and after-filter. These components remove approximately 95% of the moisture in the system when everything is operating properly.

The remaining water vapor that is condensed inside the compressor is not the real issue, it’s the oil that is carried along with this condensate. The compressor’s lubrication oil contaminates the water being removed and creates hazardous waste that cannot be discharged to ground or most waste removal systems.
The question then becomes: How do you deal with the oily condensate as it is collected from the drains each of these components? (For suggestions to answer this question, read the Four Ways to Deal with Compressor Condensate to Keep Your Company Legal and Green on our website)

Wednesday, June 28, 2017

The Dryer Light is On...Why Do I Still Have Wet Air

We all assume that if a light is on, then it must be working.

When we take a look at the refrigerated dryer in our compressor room we assume that everything is okay when the light is on. Then later that day or the next morning, someone tells us that water is showing up in the production equipment.

Due to the complexity of an air compressor system, there are a number of reasons why a working air dryer won't dry. So now what? Well, even though the dryer may be working and there are 6 simple checks that you should perform to see what is really going on in your system.

Troubleshoot Your Air Dryer in 6 Simple Steps

Step 1: Feel the cabinet opening

Do what I call the “cough test,” which is reaching to the cabinet opening in your dryer to find the condensate separator or the outlet line. It should feel very cold – around 38° F – and if it isn’t, then the dryer has a problem. Action Item: Have the refrigeration circuit checked and make sure the condenser is clean.

Step 2: Check the valves

Believe it or not, one of the most common issues is that the bypass valves are either left partially open or do not close completely. If they seem to be closed, that is good, but you might want to check further. Action Item: Check by closing all three valves and seeing if the air pressure after the last valve goes to zero - this may take a while if you can isolate system. If it doesn’t, then you need to replace the valve.

Step 3: Check the inlet temperature of the compressor

Inlet air temperatures to the dryer should be no more than 100° Fahrenheit.  If you can put your hand on the dryer inlet pipe and it doesn’t feel hot to you, then that is good. If it feels hot to the touch, that may be the problem – Action Item: Check the air-cooled or water-cooled aftercooler on the compressor to make sure it is clean and that the air temperature is no more than 15° F above room temperature . If it the aftercooler is too warm, you may have to remove it and clean it thoroughly.

Step 4: Check the ambient temperature of the compressor room

As mentioned above, your compressor room ideally should not be any hotter than the outside temperature, i.e. 90° F on a 90° F day. If the compressor room is more than 10° F above the outside temperature, you could have a problem for all of the equipment in the room since dryers are designed to run at 100° F ambient temperature. Action Item: Get your HVAC or compressor vendor to review your compressor room ventilation to keep the ambient temperature from reaching 100° Fahrenheit.

Step 5: Check for condensate in the dryer drain trap

If a sizable amount is not accumulating from the trap, it means the dryer may be working but is not removing the water. Action Item: Isolate the drain trap to clean or repair it. If you end up replacing it, REPLACE ONLY WITH A DEMAND TYPE TRAP.

Step 6: Check the low point in the piping system beyond the dryer

If there is any condensate that can be drained out, go back through the other steps. In the meantime, put a drain on this low point to help eliminate moisture in the system

If you’ve taken these six steps and everything checks out, then it’s time to call your compressed air vendor to find out what’s going on. If you can’t get the results you need, you may want to call Hope Air Systems and ask for Frank Lederer at 508-393-7660 or send him an email. (


Monday, June 19, 2017

Is Your Compressor Ready for the Summer?

Summer is a just around the corner and for those who work in a compressor room, they understand that high temperatures can affect the performance of the equipment. 

Most compressor manufacturers rate their equipment at 60° inlet and ambient room conditions. If you have 95° F ambient in the room, the compressor should run okay if properly ventilated, but will lose approximately 8% of its capacity. As the temperature increases beyond 95° F, you lose even more capacity and could start damaging the compressor.

If the coolers are not cleaned, the inlet filter has not been changed, and/or the condensers on the refrigerated air dryers are dirty, you may have operational problems and possible shutdown when the outside thermometer reaches 85° F.

Here is some advice on what you can do:

  • Prepare your compressor for the summer by reading the operator’s manual and perform the indicated service needed for high temperatures.
  • Put a thermometer in your compressor room to monitor the room temperatures. (Anything above 100° F could be damaging for your equipment).
  • Take a look at current room temperatures and compare it to the operating temperatures of the compressor and the refrigerated air dryer. (If there is more than a 15° F difference from the room temperature on the air dryer inlet air you have a problem with the coolers).
  • Increase the room ventilation to make sure that you can match outside air temperatures even in the hottest weather. You should move air through the room at least one time every 2 minutes. 

Key Temperatures to Watch: 
  • The room temperature should be no greater than 10° F more than the outdoor temperature.
  • Rotary screw compressors should not operate above 210° F
    (Most shutdown at 215/220° F. Normal operating temp in a 70° F room is 190° F).
  • The dryer inlet should be no more than 15° above room temperature.
    (95° F room = 110° dryer inlet air). 

If you operate your compressor and dryer over the design temperature you will shorten the life substantially and create wet /oily air. If you have current issues with your compressor, it would be wise to have it serviced now because it will only get worse in the hot weather. If you need assistance please contact Frank Lederer at 508-351-1817 or by email. (

Wednesday, May 3, 2017

What is a Cycling Dryer and Why Would You Want One?

Most plants currently have a dryer that continuously runs and uses a component called a hot gas bypass valve to keep the unit above 38° F and prevent it from freezing up. But, there are many different types of cycling dryers that accomplish the same result without the dryer constantly running.

  • Cycling type with a thermal mass is cooled down to the required temperature and the compressor shuts off – this works much like your refrigerator – if no load, the unit does not come back on until required – very effective and the most reliable
  • VFD cycling uses a variable speed drive on the refrigeration compressor that varies the amount of power/refrigeration used based on the temperature of the air – operates much like a variable speed air compressor – most have a range of 100% to 30% – not good in low range applications – fairly complicated electronically
  • Load/unload cycling compressors – works much like larger refrigeration systems and can be effective when they are fairly steady medium loads – can short cycle with low loads – sometimes not as power cost effective as a true cycling dryer

With that being said, if you purchase a 500 CFM dryer ($8,000) for your plant and left it on while your compressor is running (or maybe you forget to shut it off at the end of the second shift), it would use 2.5 HP continuously. If you purchase the same 500 CFM thermal mass cycling dryer ($10,200) for the same application, it would require 2.7 HP. But, in an average plant it would be on only 20-25% of the time. The cost difference between the two is $2,200 and the savings is $1,490 for $6,000 a year at $.15 a KW. Using simple math, the ROI is 1.5 years.

Other advantages of using a cycling dryer are:

  • You do not have to remember to turn the dryer off when you turn the compressor off as it shuts down
  • Potential freeze up at low load conditions almost eliminated
  • It can be used with lower CFM compressors while maintaining the same dew point
  • It will tolerate higher ambient/higher inlet temperature conditions more readily over standard dryer.
Remember all dryers are rated at 100 PSI/100° F inlet air/100° F ambient temperature. If you increase the air pressure dryer performance gets better. If the ambient air temperature or the inlet air temperature gets above 115° F your dryer could be in big trouble and moisture will soon be invading your system.

If you would like to know more about how a cycling dryer would be a better fit for you than what you have we be happy to help or if you have any moisture issues let us know. Contact Frank Lederer:

Monday, April 17, 2017

Rotary Screw and Piston Compressors On Display at No. Haven Parker Store

Jeff Haynosch

Sales Engineer

It’s exciting that in addition to the fluid power products we have been representing at Connecticut Fluid Power over the years, our joining up with The Hope Group last year has meant that we have expanded our product offering to include fluid connectors, and now, compressed air systems and service.

At the Open House and Technology Seminars on May 10, 2017, at our new Parker Store in North Haven, we will have a display as part of the Trade Show of Kaeser rotary screw compressors and Hope Air Systems’ own brand of piston compressors. Our customers always need a power source, whether it’s a generator, a hydraulic power unit, or an air compressor, and so it’s great to introduce this new line of products to the North Haven area.

You can learn more about the Technology Seminars and the Open House by visiting the website.

Wednesday, March 29, 2017

Don’t Leave Fluid Analysis Until It’s Too Late

Henry St. John
Parts Mgr, Hope Air Systems

Without proper preventive maintenance, your system could experience failures ranging from small to fatal. Routine fluid analysis is important and should be conducted on a schedule to monitor wear, determine potential failures in process, and to schedule fluid changes accurately.

Fluid analysis should not be an optional procedure left to whenever you “get around to it”. It must be routinely conducted by engineers and technicians as a tool to measure and monitor principal fluid characteristics that include metal content, water content, and viscosity.

Hope Air Systems’ engineers and technicians are ready to help with a fluid analysis to prevent costly failures and breakdowns. If you have any questions, please contact me at 508-351-1827 or by email (