Van Air Systems HL-2500 - Manual (Page 9)

PAGE 9
START UP SECTION 5
5.1 START UP
WARNING
BEFORE STARTING THIS DRYER, FOLLOW THE INSTALLATION
INSTRUCTIONS AND PROCEDURES COMPLETELY. SERIOUS
PERSONAL INJURY CAN RESULT IF INSTRUCTIONS ARE NOT
CAREFULLY AND COMPLETELY FOLLOWED.
DO NOT REMOVE, REPAIR, OR REPLACE ANY ITEM ON THIS
DRYER WHILE IT IS PRESSURIZED.
For the Standard Control Box, make sure the Stop button is pressed.
For the Cycle Saver and Emcon II Control Boxes, make sure that the
Power switch is in the OFF position.
If the dryer is being started up for the first time or after the
desiccant has been changed, the purge mufflers must be removed.
The dryer should be operated until no desiccant dust is visible at
the purge valves. Then the mufflers can be reinstalled. See
Section 2.2 for safety precautions concerning the desiccant dust.
WARNING
WHEN OPERATING THIS DRYER WITHOUT THE MUFFLERS
INSTALLED, USE HEARING PROTECTION.
If bypass piping was installed on this dryer as outlined in SECTION 4.2,
close the inlet and outlet isolation valves. Open the bypass valve.
Pressurize the air system. Once the air system is pressurized, slowly
open the inlet isolation valve. DO NOT open the outlet isolation valve.
To start the dryer with a Standard Control Box, press the Run button
which will light the Run LED. For Cycle Saver and Emcon II Control
Boxes, place the Power switch in the ON position. One tower will
already be pressurized. The other tower will depressurize. The purge
valve on the tower that is not pressurized will be open, air should be
exhausting from the muffler.
Dryers equipped with CYCLE SAVER or EMCON II controls will begin a
20 minute start up cycle. While in the start up cycle the dryer will
operate for 5 minutes on each tower to allow the humistat(s) to reach
equilibrium. Any time the dryer is restarted after a loss of power or
pressure in both towers, it will restart in the start up cycle.
The dryer is equipped with a purge metering valve. The setting should
be checked before placing the dryer on stream.
5.2 ADJUSTING THE PURGE FLOW
IMPORTANT
NEVER OPERATE THE DRYER WITH THE PURGE METERING
VALVE CLOSED. IF THE VALVE IS CLOSED, THE TOWERS WILL
NOT REPRESSURIZE AND SWITCHING FAILURE WILL OCCUR.
DO NOT ADJUST THE PURGE METERING VALVE ABOVE OR
BELOW THE RECOMMENDED SETTING FOR THE OPERATING
CONDITIONS OF THIS INSTALLATION. IMPROPER SETTING MAY
CAUSE POOR DRYER PERFORMANCE AND/OR EXCESSIVE USE
OF PROCESS AIR.
The purge flow can be adjusted for the operating conditions. Standard
dryers are equipped with a micrometer type needle valve. The valve can
be adjusted to the desired setting.
This dryer was shipped with the purge flow set for the rated inlet flow at
100 PSIG. Reference Section 3.1 for rated flow. This setting should be
correct for most installations. Before placing the dryer on stream, check
the purge metering valve setting.
Figure 5B shows the purge flow required for each model. This flow is
required to properly regenerate the desiccant beds.
If the dryer is being operated at a pressure other than inlet rated
MODEL
HL-2500
60 PSIG
4.5 turns
80 PSIG
4.2 turns
FACTORY
SETTING
100 PSIG
4.0 turns
120 PSIG
3.5 turns
150 PSIG
3.2 turns
FIGURE 5A PURGE METERING VALVE SETTINGS
FIGURE 5B REQUIRED PURGE FLOW
DRYER
MODEL
HL-2500
5.3 CONDITIONING THE DESICCANT BED
To condition the desiccant bed, the dryer is operated without any outlet
flow, while the towers regenerate with purge air.
To start the dryer with a Standard Control Box, press the Run button,
which will light the Run LED. For Cycle Saver and Emcon II Control Boxes,
place the Power switch to the ON position.
Dryers equipped with the Standard Contol Box should be set on the 10
minute time cycle. Dryers equipped with Emcon II and Cycle Saver
should be set in the Fixed Mode. Observe the dryer for several cycles.
Make sure that it is operating properly.
At initial start up or after extended shutdowns (over one month), the dryer
may take 24 to 48 hours of continuous operation for the bed to be
conditioned. Moisture that has accumulated on the desiccant bed should
be removed before the dryer is placed on stream.
Once the moisture indicator on the dryer turns blue, the desiccant bed
is ready. Place the dryer on stream by opening the outlet isolation valve.
Make sure that the by-pass valve is closed.
PURGE
FLOW
450 SCFM
conditions, the purge metering valve must be adjusted to maintain the
required purge flow rate listed in Figure 5B.
Determine the dryer minimum operating pressure. Using the chart in
Figure 5A, find the valve setting for that pressure. The valve is equipped
with a set screw which must be loosened before the valve is adjusted.
Adjust the needle valve to the desired setting. Tighten the set screw to
prevent tampering.