Refrigerated dryer PM
Condenser clean, drain test, and dewpoint verification on a refrigerated dryer.
This guide is general field reference for trained, qualified service technicians. It is not a substitute for the original equipment manufacturer's service manual, applicable codes (NEC, OSHA, ASME, local), or the judgment of a licensed professional. Procedures, torque values, pressures, refrigerants, and safety requirements vary by make, model, jurisdiction, and revision. Always verify against current OEM documentation and follow your employer's safety program. Working on compressed-air, electrical, pressure-vessel, and refrigerant systems can cause serious injury or death. By using this guide you accept all risk; AirCompDX and its authors disclaim all warranties and are not liable for any damage, injury, loss, or code violation arising from its use.
LOTO and bleed dryer to 0 psi for drain service. R-410A and R-134a refrigerant work is EPA Section 608 only.
- Coil comb / fin brush
- Compressed air (low pressure)
- Calibrated dewpoint meter
- Auto drain rebuild kit
- Pre-filter and after-filter elements
- 1Clean condenser coil
Air-cooled dryers fail high-side first when the coil plugs. Brush and blow out fins; fix any bent fins with a comb.
- 2Test auto drain
Cycle the drain manually — full open, full close, no continuous bleed. Rebuild if the float sticks or the solenoid passes.
- 3Verify dewpoint
Insert dewpoint probe in the dryer outlet sample port. Target ≤38–50°F PDP per OEM rating. Higher = low refrigerant charge, hot ambient, or overload on flow.
- 4Check ΔP
Measure pre- and after-filter ΔP. Replace elements above 8–10 psi total ΔP across the filter set.
- 5Log
Record PDP, condenser inlet/outlet ambient, ΔP, and amp draw for trending.