Gardner Denver EBB BB-7.5 HP Operating And Service Manual page 47

SYMPTOM
Erroneous Pressure Readings
[135 – 150 psig constantly].
(9.3 – 10.3 Bars)
Oil leak at the bottom of
the seal housing.
Fuse on board blows.
Fuse on transformer blows.
Gardner Denver factory remanufactured replacement compressor air end units
are available from your authorized distributor, on an exchange basis, for all rotary
screw compressor units.
POSSIBLE CAUSE
1. Electrical noise creating
false readings.
2. Loose connector.
3. Bad transducer.
1. Gasket leaking.
2. Plug leak.
3. Capscrew leaking.
4. Shaft seal leaking.
1. Board damaged by
high voltage.
1. Shorted coils on hour
meter, starter coil,
or blowdown valve.
13–8–612 Page 37
REMEDY
1. Make sure transducer wires
are kept to a minimum length
and are twisted.
2. Measure the DC voltage
between the green and black
wires of the corresponding
transducer at the control
board with zero pressure on
the transducer. If .460 to
.540 volts, replace the plug–
gable connector that con–
nects transducers to the
board.
3. Measure the DC voltage
between the green and black
wires of the corresponding
transducer at the control
board with zero pressure on
the transducer. If below .450
or over .550 volts, replace the
transducer.
1. Replace the gasket.
2. Repair.
3. Repair.
4. Change seal.
1. Remove all power from the
unit by opening the main
disconnect, replace fuse,
energize main power. If fuse
blows – replace board.
1. If fuse does not blow, check
for shorted coils.