Returns to Manufacturer
If the dryer or a component of the dryer must be returned
to the manufacturer, first call your local distributor for a
return authorization number and shipping address. Your
distributor will inform you whether the dryer or only a
component must be returned. Mark the package with the
return authorization number and ship freight prepaid as
directed by your local distributor.
FIELD SERVICE GUIDE
Problems most frequently encountered with refrigerated
dryers are water downstream of the dryer and excessive
pressure drop. Most causes can be identified and reme-
died by following this guide.
PROBLEM
SYMPTOM(S)
No discharge from
separator drain trap. Failure of separator.
Dryer inlet air tem-
perature too high.
Water down-
stream of
dryer
Refrigerant compres-
sor stopped.
Low outlet pressure.
High pressure
drop
Lowest process air
temperature below
32°F (check at sepa-
rator).
Indicator in
red zone
Indicator in
blue zone
SDR Series (Bulletin 546)
POSSIBLE CAUSE
Dismantle and clean, repair or replace separator.
Aftercooler malfunc-
Check aftercooler discharge temperature and reduce to dryer de-
tion.
sign condition (120°F max.).
1. Leak in refrigera-
1. Consult your local distributor.
tion system.
2. Compressor over-
2. Turn dryer off. Wait 30 minutes; turn dryer on. (Motor thermostat
heated.
self-starting.)
3. Compressor
3. Consult your local distributor.
burned out.
1. Dryer undersized
(may also cause wa-
1. Check airflow and dryer capacity. Reduce airflow or resize and
ter downstream of
replace dryer.
dryer)
2. Blocked separator 2. Dismantle and clean or replace separator.
Dryer icing up.
Consult your local distributor.
1. Adjust valve.
Models SDR7 – 25: the valve can be adjusted through the access
area. Using a nut driver, turn the nut counterclockwise until the
gauge is in the green zone.
Models SDR35 – 50: remove the cover on the end of the valve to
gain access for adjustment. Using an allen wrench, turn the nut
counterclockwise until the gauge is in the green zone. Replace
cover.
1. Adjust valve.
Models SDR7 – 25: the valve can be adjusted through the access
area. Using a nut driver, turn the nut clockwise until the gauge is in
the green zone.
Models SDR35 – 50: remove the cover on the end of the valve to
gain access for adjustment. Using an allen wrench, turn the nut
clockwise until the gauge is in the green zone. Replace cover.
2. Reduce ventilation. Move dryer out of breezes.
DANGER
Closed refrigeration systems are potentially
dangerous. Work on the refrigeration system
must be done only by a competent refrigeration
mechanic.
Do not release fluorocarbon refrigerants to the
atmosphere. All refrigerants must be recovered
per EPA requirements.
Do not smoke when a refrigeration leak is
suspected. Burning materials may decompose
refrigerants, forming a toxic gas or acids that
may cause serious injury and property damage.
Before working on any part of the dryer or
compressed air system, completely vent the
internal pressure to the atmosphere.
REMEDY
1-5