Specifications

Maintenance, troubleshooting, spares and dismantling
DRYPOINT RA 80 – 720 33
6.2. Troubleshooting
Only qualified personnel should perform troubleshooting and or maintenance operations.
Prior to performing any maintenance or service, be sure that:
• no part of the machine is powered and that it cannot be connected to the mains supply.
• no part of the machine is under pressure and that it cannot be connected to the compressed air
system.
• Maintenance personnel have read and understand the safety and operation instructions in this
manual.
Before attempting any maintenance operation on the dryer, shut it down and wait at least 30 minutes.
Some components can reach high temperature during operation. Avoid contact until system or component
has dissipated heat
SYMPTOM POSSIBLE CAUSE - SUGGESTED ACTION
 The dryer doesn't
start.
 Verify that the system is powered.
 Verify the electric wiring.
 Intervention of the electric protection (see Q3/Q4 on the electric diagram) of the
auxiliary circuit - restore it and check the proper operation of the dryer.
 DRYPOINT RA400-720/AC - The back panel of the dryer is open (SD door interlock
safety-switch has been activated) - make sure the back panel is correctly closed and
the SD switch restored.
 DMC14- The “alarm” led is ON - see specific point.
 DMC20- The “alarm” led is ON - see specific point.
 The compressor
doesn’t work.
 Activation of the compressor internal thermal protection - wait for 30 minutes, then
retry.
 Verify the electric wiring.
 The high pressure switch PA has been activated - see specific point.
 The low pressure switch PB has been activated - see specific point.
 The safety thermo-switch TS has been activated - see specific point.
 DMC14- The “alarm” led is ON - see specific point.
 DMC20- Internal delay device – wait at least 4 min from last shut-off.
 DMC20- The “alarm” led is ON - see specific point.
 If the compressor still doesn’t work, replace it.
 The fan of the
condenser doesn’t
work (Air-Cooled).
 Verify the electric wiring.
 DRYPOINT RA 80-360- PV pressure switch is faulty - contact a refrigeration engineer.
 DRYPOINT RA 400-720- PV1-PV2 pressure switches are faulty - contact a
refrigeration engineer.
 The fan power contactor (see V / V1 / V2 on the electric diagram) is faulty - replace it.
 DMC14- The “alarm” led is ON - see specific point.
 DMC20- The “alarm” led is ON - see specific point.
 There is a leak in the refrigerating fluid circuit - contact a refrigeration engineer.
 If the fan still doesn't work, replace it.
 DewPoint too high.
 The dryer doesn't start - see specific point.
 The T1 DewPoint probe doesn’t correctly detect the temperature - ensure the sensor is
pushed into the bottom of copper tube immersion well.
 The Compressor doesn’t work - see specific point.
 The ambient temperature is too high or the room aeration is insufficient - provide
proper ventilation (Air-Cooled).
 The inlet air is too hot - restore the nominal conditions.
 The inlet air pressure is too low - restore the nominal conditions.
 The inlet air flow rate is higher than the rate of the dryer - reduce the flow rate - restore
the normal conditions.
 The condenser is dirty - clean it (Air-Cooled).
 The condenser fan doesn’t work - see specific point (Air-Cooled).
 The cooling water is too hot - restore the nominal condition (Water-Cooled).
 The cooling water flow is insufficient - restore the nominal condition (Water-Cooled).
 The dryer doesn’t drain the condensate - see specific point.
 The Hot Gas By-pass Valve is out of setting - contact a refrigeration engineer to restore
the nominal setting.
 There is a leak in the refrigerating fluid circuit - contact a refrigeration engineer.