Sullair SD-1050 Series, User Manual

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USER MANUAL
Models SD-820 to SD-1710 with DDS
Rev 04 – October 2005
APPENDIX A OPERATING SEQUENCE
A-1
APPENDIX A – DRYER OPERATING SEQUENCE
This dryer uses a printed circuit board (PCB) as its standard controller. In the event of a
power failure, the inlet valves will open and the dryer will pressurize both chambers.
Since this control panel uses retentive programming, the dryer will return to the step in
the cycle where dryer was before power was removed.
NOTE: If power failure occurs to the dryer or unit is turned off, both exhaust
valves will close. Both inlet valves will remain open.
Set switch to DRYER ON. The electrical circuit is energized. Table A-1 presents the
dryer operating logic.
TABLE A-1 DRYER STEP SEQUENCE
STEP FUNCTION PROCESS
1
SELECT LEFT
CHAMBER DRYING
De-energize solenoid EV-1R.
Energize solenoid EV-1L.
Inlet valve positioned for left chamber drying.
When 3 seconds have passed, go to next step.
2
DEPRESSURIZE
RIGHT CHAMBER
Keep EV-1L energized.
If in DRYER ON mode:

Energize EV-2R opening right chamber
dump/exhaust valve.
If in DDS ON mode and dew point is better than
hygrometer set point:

EV-2R does not energize.
When regeneration time has passed, go next step.
3
REPRESSURIZE
RIGHT CHAMBER
Keep EV-1L energized.
De-energize EV-2R: close right chamber dump/exhaust
valve.
The repressurization timer begins a countdown of 40
seconds.
Inlet valve remains in current position.
When repressurization time has passed, go to next step
NOTE: EV-3 and repressurization valves may be used if dryer is operating at
pressure above 125 psig and/or dryer is operating on a timing cycle other
than the 10-minute cycle. Refer to paragraph 1.4 in this manual or to
section 7, the flow schematic.
4
SELECT RIGHT
CHAMBER DRYING
De-energize solenoid EV-1L.
Energize solenoid EV-1R.
Position inlet valve for right chamber drying.
When 3 seconds have passed, go to next step.