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. (FLederer@HopeAir.com)


 

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. (FLederer@hopeair.com).