SKF SFD - Page 50

cycles pneumatically thereby cutting of continuous purge flow during compressor “off” or non-pumping
cycle.
When an SFD cycles, there will be a momentary burst of air from one SFD exhaust port (muffler). This is
normal and will occur each time dryer cycles. Four cartridge MLT systems will have two cartridges
regenerating one from each dryer unit, e.g., cartridges 1, 3 charge cycle, cartridges 2, 4 regeneration cycle
MLT (Micro Logic Timer)
refer to pg. 15
G
Regeneration Cutoff
Solenoid (RCS)
E
Air Control Valve 1
#619925
E
Air Control Valve #2
#619755
Connect Wires to Air Compressor
Pressure Control Switch
Possible Cause
Regen air does not stop when compressor pump is off
Cracked or broken pilot signal hose #1 to air control #2
Plug vents
Defective coil and/or air control valve
RCS and Air Control valve test procedures
Dryer does not cycle every two minutes when
compressor is on
RCS (Regeneration Cutoff Solenoid)
Refer to Micro Logic Timer (MLT) section: Dryer will not cycle
(switch) every two minutes w/Micro Logic Timer on pg. 15
Step 1: Disconnect coil from air compressor pressure
control switch.
Step 2:
With compressor pumping , manually cycle air
control valve by turning brass screw in air control valve to
2
o’clock (1
/4
turn right) and back to 12
o’clock position. If
regen stops flowing, replace coil assembly "G". If regen
does not stop flowing, proceed next step
Step 3: Replace air control valve "E", reinstall RCS onto air
contol vlave and reconnect electrical connections to
pressure control switch. Note: make sure brass screw is in
12 - 6 o'clock position for normal operation
E
G
Remedy
Check ekectrical connection on compressor pressure switch
Replace
¼″ hose
Remove vents, clean and reinstall
Brass Screw
Vents
G
E
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