Industrial air dryer service
Air dryer service for refrigerated compressed air dryers: we measure the pressure dew point, repair the refrigerant circuit, clean heat exchangers and restore the condensate drains, so that no water reaches your production air network.
F-gas company certificate. A report with measurements after every visit. Mobile service in Poland and the EU.
What a refrigerated dryer does
Compressed air leaving an aftercooler is saturated with water vapour. A refrigerated dryer cools it to about +3 °C, the water condenses and is separated and drained, and the air is reheated in an air to air exchanger before it enters the network. The result is a pressure dew point of +3 °C to +7 °C, which corresponds to classes 4 and 5 for humidity in ISO 8573-1. When the dryer fails, water appears in pneumatic valves, cylinders, paint lines and packaging machines within hours. Air dryer service is therefore preventive work as much as repair.
Main components
- Air to air heat exchanger, which precools incoming air and reheats outgoing air.
- Air to refrigerant exchanger (evaporator), where the air reaches the dew point.
- Water separator and condensate drain: timed solenoid drain or level-controlled zero air loss drain.
- Refrigerant circuit with compressor, condenser (air or water cooled), capillary or expansion valve and hot gas bypass valve.
- Controller with dew point indicator and alarms.
Dew point measurement
The dew point indicator on many dryers shows the evaporator temperature, not the real humidity of the air. We measure the pressure dew point with a calibrated hygrometer probe at the dryer outlet under actual load. The comparison often explains complaints about water in the network: the display shows +3 °C while the air leaving the dryer has a dew point of +12 °C because water is carried over past a flooded separator.
Typical faults
| Symptom | Possible causes |
|---|---|
| High dew point, dryer running | Dryer overloaded (flow, inlet temperature or ambient above rating), dirty condenser, low refrigerant charge |
| Water in the network, normal display | Blocked or failed condensate drain, water carry-over, bypass valve open |
| Evaporator freezing, pressure drop rising | Hot gas bypass valve out of adjustment, very low air flow at night |
| High pressure trip | Condenser blocked with dust, fan failure, cooling water too warm or too little |
| High pressure drop across the dryer | Fouled exchangers, ice, blocked inlet filter |
Overload is the most common cause
Dryer capacity is rated at reference conditions, usually 35 °C inlet air, 25 °C ambient and 7 bar. With 45 °C inlet air from a poorly maintained aftercooler and a 35 °C compressor room, the same dryer can handle only around half of its nominal flow. Before repairing anything, we measure inlet temperature, ambient temperature and pressure and compare them with the correction factors of the manufacturer.
Drains
Timed drains with blocked strainers and level drains with dirty sensors are responsible for a large share of “dryer failures”. We clean or replace the drains, check the drain line and test the function under load.
Refrigerant circuit
Dryers use R134a, R407C, R410A or, in newer models, R513A and other lower-GWP refrigerants. We measure suction pressure (which directly sets the dew point), superheat, the hot gas bypass setting and compressor current. Leaks are repaired by brazing, followed by evacuation and charging by weight. Many small dryers fall below the leak check threshold: 1.5 kg of R134a equals 2.1 t CO2 eq. Larger units do not; 3 kg of R407C (GWP 1774) gives 5.3 t CO2 eq. and a 12-month leak check interval under Regulation (EU) 2024/573.
Heat exchangers and cleaning
Oil aerosols and pipe scale from the compressor side build up in the air to air exchanger and the evaporator, raising the pressure drop. Every 0.1 bar of extra pressure drop has to be compensated by the compressor, which costs energy all year. We measure the pressure drop across the dryer and, where needed, clean the exchangers. Air-cooled condensers in compressor rooms collect dust quickly and are cleaned at every visit.
Scope of an inspection
- Measurement of pressure dew point, inlet and ambient temperatures and pressure.
- Check of the condensate drains and the separator.
- Cleaning of the condenser and check of the fan.
- Refrigerant circuit measurements and leak check.
- Pressure drop across the dryer and the filters.
- Electrical checks and test of alarms.
Dryers are often installed next to process coolers and oil coolers in the same plant; see industrial coolers. All of them can be included in one schedule of planned maintenance. A broader assessment of all refrigerating equipment on site is offered as a refrigeration system audit.
Questions from maintenance teams
Do you service the compressors too?
Our scope is the dryer and its refrigeration circuit. Air compressors themselves are usually serviced by compressor specialists, and we coordinate with them where the aftercooler affects the dryer.
Can a dryer be repaired in your workshop?
Yes, smaller dryers can be repaired in Wałsnów, pressure tested and run before return.
Why is there water in the network after a new dryer was installed?
Often because water had already collected in the pipes before, or because of a bypass, a missing drain or an overloaded dryer. A dew point measurement at several points finds the source.
Which dew point do we need?
For most production air indoors, +3 °C is sufficient. Air for pipes running outdoors in winter or for sensitive processes needs a lower dew point, which requires adsorption dryers.
Water in your compressed air?
Send the dryer nameplate and a description of the problem, and we will plan a measurement and repair.