Pub. No. OM-A-75 REV. 4 — March 2006
7
d. Hot gas line valve – Models AD(W)-2500 &
larger. Located on the hot gas line before the Hot
Gas Bypass Valve.
e. Liquid line valve on water-cooled condenser
outlet (water-cooled models only).
6.
Turn the power ON/OFF switch to the ON position.
7.
The suction pressure will gradually come down to the
blue or green range depending on the type of
refrigerant used in the air dryer. Check the
refrigerant suction pressure gauge reading. If the
suction pressure is above or below the suggested
color range, a hot gas bypass valve adjustment is
required. (Refer to the Hot Gas Bypass Valve section
of this manual.) For proper operating range and
control settings see listing below.
8.
The Expansion valve is factory set for the correct
superheat of 8-10°F and should not be re-adjusted. If
any malfunction is noticed on the expansion valve,
contact the factory or your Pneumatech distributor.
9.
Allow 10 to 15 minutes of cooldown time before
adding the compressed air load.
10. Keeping the dryer outlet isolation valve closed,
pressurize the dryer to the line pressure. See
Figure 1.
11. Check for any leaks in the system.
12. Slowly open the dryer outlet isolation valve to
pressurize the downstream system.
OPERATING RANGE AND CONTROL
SETTINGS
1.
Refrigerant Suction Pressure:
53 to 60 PSIG (Refrigerant-22)
(R-22 Green color range)
25 to 33 PSIG (Refrigerant-134a)
(R-134a Blue color range)
2.
Refrigerant Discharge Pressure (R-22):
135 to 275 PSIG (R-22) air-cooled units with fan
cycling; 190 to 210 PSIG (R-22) water-cooled units
3.
Refrigerant Discharge Pressure (R-134a):
75 to 170 PSIG (R-134a) air-cooled units;
115 to 135 PSIG (R-134a) water-cooled units
4.
Refrigerant Low Pressure Switch:
CUT OUT 20 PSIG (R-134a)
CUT IN 40 PSIG (R-134a)
CUT OUT 45 PSIG (R-22)
CUT IN 70 PSIG (R-22)
5.
Refrigerant High Pressure Switch:
250 PSIG (R-134a) air-cooled units
405 PSIG (R-22) air-cooled units
(375 PSIG*) (R-22) air-cooled units
(325 PSIG*) (R-22) water-cooled units
6.
Fan Control (R-134a):
CUT OUT 110 PSIG
CUT IN 150 PSIG
7.
Fan Control #1 (R-22):
CUT OUT 175 PSIG (180 PSIG*)
CUT IN 230 PSIG (220 PSIG*)
8.
Fan Control #2 (R-22):
CUT OUT 195 PSIG (190 PSIG*)
CUT IN 250 PSIG (230 PSIG*)
* Settings indicated in parentheses are for units equipped
with adjustable pressure switches.
Consult factory for pressure switch settings on dryers
equipped with optional Low Ambient Headmaster control.
DIGITAL DRY GUARD™ (DDG)
CONTROLLER OPERATION
(Available on some models as standard and others as an
option.)
The DDG Controller is capable of 4-channel temperature
display, drain control, and service due and alarm
indication.
Temperature Display
The DDG controller is capable of 4-channel temperature
display. The unit displays refrigerant suction temperature
(measured immediately downstream from the refrigerant/
air heat exchanger), incoming air temperature, ambient
air temperature (or incoming water temperature for units
with a water-cooled condenser), and dew point
temperature (optional). Only one temperature can be
displayed on the LCD screen at a time. In the normal
operational mode, pushing the UP (
↑
) or DOWN (
↓
)
arrow keys will cycle the temperature displayed, while
