8
Pub. No. 2200772355 — October 2006
START-UP AND OPERATION
PRELIMINARY CONTROLS
Before starting the dryer, check for:
1.
The correct connection to the compressed air piping:
remember to remove end caps on the dryer inlet and
outlet.
2.
The correct connection to the condensate drainage
system.
3.
The correct power supply.
STARTING AND STOPPING
Always start the dryer at least 5 minutes before the air
compressor starts running and stop it after the air
compressor has been stopped in order to keep the
compressed air piping free of condensate. The dryer must
be kept running while the air compressor is running.
PRESSURE DISCHARGE PROCEDURE
See Figure 13 on Page 10.
1.
Isolate the dryer from the air system (1).
2.
Release the pressure in the dryer by pressing the
condensate drain “TEST” pushbutton located on the
auto drain (2).
3.
Switch off the machine by turning the STOP button to
position “0 OFF” (3).
4.
Turn off the power supply by opening the circuit
breaker or fused disconnect switch (4).
CALIBRATIONS
HOT GAS BYPASS VALVE
These valves have already been calibrated and they do
not require any adjustment. A dew point different from the
rated one generally is caused by factors which are not
attributable to their operation. Figure 10 shows:
1.
Closing cap
2.
Adjusting screw
This valve maintains the
refrigerant suction pressure in
varying load conditions. The
dryer will run from no load to
full load conditions without
freeze-up. The operation of this
valve is automatic. If the valve
needs adjustment, turn the
adjusting stem clockwise to
raise the suction pressure, and
counterclockwise to lower the suction pressure. This
adjustment should be made under a no-load condition if
possible. When the adjustment is made, turn one quarter
of a turn at a time, and wait 3 to 5 minutes between
adjustments. Careful adjustment of this valve is necessary
for normal operation of the air dryer. Hot gas bypass
valve adjustment may be made by maintenance
personnel. (See Figure 10.)
Table 2 — WORKING PRESSURES AND
TEMPERATURES OF R134A
Before making any change to the machine,
ensure that the electric power supply has
been disconnected. Wait at least two hours
before starting up after any machine
movement (transport or handling).
The following procedure must be per-
formed by skilled personnel approved by
the manufacturer.
If the dryer is switched off, before starting
it again, wait at least 5 minutes to allow
for pressure balancing.
SUCTION SIDE OF
REFRIGERATION COMPRESSOR
Evaporating
Temperature
°F (°C)
Evaporating
Pressure
psi (bar)
RATED VALUES
AT AMBIENT
TEMPERATURE
+68 °F (+20 °C)
33.8 - 35.6
(1 - 2)
R134A
29 - 31
(2.1 - 2.3)
2
1
FIGURE 10 —
BYPASS VALVE
