Figure 11-2 Temperature-Pressure Chart (R-22); Figure 11-3 Adjusting Nut For Suction Pressure - Gardner Denver EBB BB-7.5 HP Operating And Service Manual

Temperature
F
28
30
32
34
36
38
40
45
50
55
60
button, "MOTOR RUN" indicator and an "ALARM" indi-
cator light.
The compressor fan motor is directly controlled by
pressure switch S2 when the dryer is in the "MOTOR
RUN" mode. Pressure switch S2 will close to activate
the fan motor when the dryer compressor discharge
pressure reaches 195 PSI. The fan motor will continue
to operate until the dryer compressor discharge pres-
sure decreases to 150 PSI causing pressure switch S2
to open.
The "ALARM" circuit in the EBB integrated dryer is con-
trolled by pressure switch S1 which will open if the dryer
compressor discharge pressure reaches 375 PSI. This
condition will cause the dryer unit to shutdown and the
"ALARM" indicator to be lit. The unit cannot be re-
started until the dryer compressor discharge pressure
decreases below 300 PSI causing pressure switch S1
to close and the "ALARM" indicator to be extinguished.
Refer to the troubleshooting guide in the event of an
"ALARM" condition.
The EBB integrated dryer must be manually restarted
in the event of a power failure.
The noncycling operation of the refrigerated dryer is
controlled by two modulating valves. The hot gas by-
pass valve is used in conjunction with the capillary tube.
This valve automatically opens and closes depending
on the amount of cooling required, thus maintaining the
design pressure dew point. The hot gas by–pass is
preset at the factory. The suction pressure gauge
TEMPERATURE–PRESSURE CHART (R–22)
Pressure
psig
52.4
54.9
57.5
60.1
62.8
65.6
68.5
76.0
84.0
92.6
101.6
FIGURE 11–2 – TEMPERATURE–PRESSURE CHART (R–22)
13–8–612
Temperature
F
65
70
75
80
85
90
95
100
105
110
should indicate 65 psig for R–22. If adjustment is nec-
essary, refer to FIGURE 11–3.
Increasing the suction pressure will
raise the evaporator temperature.
Decreasing the suction pressure will
lower the evaporator temperature.
FIGURE 11–3 – ADJUSTING NUT FOR SUCTION PRESSURE
Page 61
Pressure
psig
111.2
121.4
132.2
143.6
155.7
168.4
181.8
195.9
210.8
226.4