Van Air Systems HL-200 - HL2000 - Manual (Page 14)

PAGE 14
USING THE STANDARD CONTROL SECTION 7
7.1 STANDARD CONTROL
The STANDARD CONTROL is a compact NEMA 4X control box. It has the
following features:
• Dryer Status LEDs
- POWER ON
- L/R TOWER DRYING
- RUN - L/R TOWER REGENERATING
- HOLD - DRYER PURGING
- SWITCHING FAILURE
The Dryer Status LEDs are located on the front panel of the control box.
Figure 7A shows the location of each. Note: There is a Red LED located
on the inside of the control box. This LED flashes on and off indicating
the timer is active.
Start the dryer per SECTION 5.1. When the Left tower is pressurized and on
line drying the process air, the corresponding LEFT TOWER DRYING LED is
illuminated. When the right tower is pressurized and on line drying the
process air, the corresponding RIGHT TOWER DRYING LED is illuminated.
The DRYER PURGING LED is illuminated when the corresponding purge
exhaust valve is open. During repressurization this LED will not be illumi-
nated. Repressurization occurs for approximately 20 seconds just before
tower changeover. The operation timing sequence of the dryer is shown in
Figure 7C TIMING CHART FOR STANDARD CONTROL.
FIGURE 7A CONTROL BOX FRONT PANEL
SWITCHING FAILURE:
When there is a switching failure, the LED will be lit. This will energize the
contacts shown in Figure 4C. The contacts can be wired for remote
annunciation. To reset the Switching Failure Alarm press the Run button
on the control box front panel.
HOLD FEATURE:
For Low load or Static pressure conditions, the hold contacts shown on
Figure 4C can be wired to an auxiliary set of normally closed contacts on
the compressor starter. This will stop the cycling of the dryer and
repressurize both towers of the dryer, until there is demand on the
compressor. The Hold LED will light, if the dryer is wired as described and
the compressor is not running.
IMPORTANT
Operating this dryer on the 4 minute cycle will more than
double the wear on the dryer components. To reduce wear on
the dryer, operate the dryer on the 10 minute cycle if the -40
O F
dew point is acceptable.
7.2 SETTING THE CYCLE TIME
Reference Figure 7B:
The setting for the time cycle is a 5 min/half cycle. For the half cycle
time setting, the switches indicated for DS1 (2, 5, 7, & 8) as shown in
the CYCLE TIME DETAIL have been factory set by pushing the
switches up. The values for these switches are (256, 32, 8, & 4) sec.,
so when added together equal 300 sec or 5 min. WE DO NOT
RECOMMEND a time cycle setting below 2 min/half cycle. For this
half cycle time setting, the switches that need to be pushed up are DS1
(4, 5, 6, & 7) their values are (64, 32, 16, & 8) sec. so when added
together equal 120 sec or 2 min.
The setting for the pressurization time is 20 sec. For the pressuriza-
tion time setting, the switches indicated for DS2 (2 & 4) as shown in
the CYCLE TIME DETAIL have been factory set by pushing the
switches up. The values for these switches are (16 & 4) sec., so when
added together equal 20sec. WE DO NOT RECOMMEND CHANG-
ING THIS SETTING.
The setting for the alarm time is 96 sec. For the alarm time setting,
the switches indicated for DS2 (5 & 6) as shown in the CYCLE TIME
DETAIL have been factory set by pushing the switches up. The values
for these switches are (64 & 32) sec., so when added together equal
96 sec. WE DO NOT RECOMMEND CHANGING THIS SETTING.
NOTE: THE ALARM TIME SETTING NEEDS TO BE LESS THAN
THE HALF CYCLE TIME SETTING OR THIS WILL NEGATE
THE ALARM FUNCTION.
FIGURE 7C TIMING CHART FOR STANDARD CONTROL
FIGURE 7B CYCLE TIME DETAIL
LEFT RIGHT
POWER ON STOP RUN RUN
TOWER DRYING
HOLD SWITCHING FAILURE
TOWER REGENERATING
DRYER PURGING
5 6
FTS
ALARM