SECTION 7 DHL HEATLESS REGENERATIVE DRYER
 45
Dryer does not 
perform the 
switching cycles.
• Solenoid valve PVA and/or PVB are never activated - see specific point.
• Inlet and/or outlet shuttle spool valve is blocked – carry out maintenance
• operations.
All the inlet air is 
discharged through 
the silencers.
• The dryer does not perform the switching cycles—see specific point. 
• The solenoid valve PVA and/or PVB is blocked—open and clean it.
• The membrane of solenoid valve PVA and/or PVB is broken—carry out mainte-
nance operations.
• The SHDC-2100 Electronic controller always supplies solenoid valve PVA and/or
• PVB – verify the electric wiring and if necessary replace.
• The cycle times on the SHDC-2100 electronic controller have been changed—
restore nominal conditions. 
• Regeneration nozzle is clogged—open and clean it.
Liquid comes out of 
the silencers.
• Humidity in outlet air – see specific point.
LED  
“HI PDP” of the 
SHDC-2100 device 
flashes or is on.
The probe of the DewPoint Meter (optional) detects a high DewPoint, for one of the following 
reasons: 
• Humidity at dryer outlet—see specific point.
• The air flow adjuster setting has been changed (see Section 6.14)—reset
nominal value.
• The selector valve of the operating tower (see Section 6.14) is blocked—
replace it.
• Verify the electric connection of the probe.
• The probe is not calibrated—contact the dealer.
• The probe is broken—replace it.
• There is an air leak on the pipes and/or joints that connect the equip-
ment— verify the connections and replace the damaged parts.
• A pipe or a joint which connects the equipment is clogged—replace it.
The LED   
“FAIL TO SWITCH” 
of the SHDC-2100 
device flashes or is 
on.
The pressureswitches(optional)forthe“FAILTOSWITCH”function,show an anomalous condi-
tions during the tower switching process, for one of the following reasons:
• The dryer does not run the switching cycle – see specific point. 
• All the inlet air is purged through the silencers – see specific point.
• The solenoid valve PVA and/or PVB is never enabled – see specific point.
• The pressure switches are not calibrated – reset the default settings (see
Section 6.17). 
• There is an air leak on the pipes and/or joints that connect the equipment
–verify the connections and replace the damaged parts. 
• A pipe or a joint which connects the equipment is clogged – replace it.
PROBLEM POSSIBLE CAUSE - SUGGESTED ACTION