Section 10
DRYER MAINTENANCE
AND TROUBLESHOOTING
40
10.4 TROUBLESHOOTING--DRYER (continued)
SYMPTOM PROBABLE CAUSE REMEDY
HEAD PRES SURE TOO LOW Low Ambient Temperature Increase ambient temperature.
Ifambient temperature is toolow, dryer freeze---up
can take place.
Add some type of head pressure control.
Refrigerant Shortage Checkf orleaksinsystem;repairandrecharg ewith
proper amount---see Section 3, Specifications.
Defective Fan Control Switch Replace. Fanshouldcut out at170 psig(11.7bar).
SUCTIONPRESSURETOOLOW HotGasBypassValveOutof Adjustorreplace.
Adjustment or Defective Turn clockwise to increase suction pressure; See
Section 8.5 for normal operating conditions.
Refrigerant Shortage AddenoughrefrigeranttomaintaindesIredsuction
pressure.
Also check amp erage draw.
Excessive Pressure Drop in High Side Check for any restriction (plugged filter dryer).
Suction pressureshouldbe steady and vary only 1
to 3 psig (0.07 to 0.2 bar) from high to low at this
condition.
Head Pressure Too Low Due to Replace.
Defective Fan Control Switch
SUCTION PRESSURE TOO HIGH Hot Gas Bypass V alve Out of Turncounterclockwise to lower suction pressure to
Adjustment or Defective desired reading.
Compressed air dewpoint will rise as the suction
pressure increases.
Refrigerant Overcharge Excessrefrigerant;checkunit’snameplatefortotal
system refrig erant charge.
Refrigerant overcharge may cause system not to
perform properly and efficiently.
WATER IN THE CO MPRES SED Drain Traps Clogged Disassemble and cleantrapstorestorefree flowof
AIR SYSTEM drainage.
Check drain lines.
Automatic drain traps are ballfloat type and do not
need priming. They should be disassembled and
cleaned after two weeks of operation.
Improperly Set or Malfunctioning Will be indicated by suction pressure being too
Hot Gas Bypass V alve, or Cycling high. Adjust or replace.
Switch
Ambient Temperature is Too High Reduce ambient or improve ventilation.
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