Gardner Denver EBB BB-7.5 HP Operating And Service Manual page 75

SYMPTOM
High suction pressure
(62 to 72 psig normal)
Low suction pressure
(62 to 72 psig normal)
Moisture in air system
downstream.
High pressure drop in
dryer air circuit.
POSSIBLE CAUSE
1. Excessive air load exceeding
the capacity of the dryer.
2. Hot gas by–pass valve setting
too high.
3. High ambient condition.
1. Low or no air load.
2. Fan not cycling at low load.
3. Hot gas by–pass valve setting
too low.
4. Refrigerant leak.
5. Low ambient temperature
and fan not cycling.
1. Dryer overloaded (air flow).
2. Separator drains not functioning. 2. Inspect automatic drain and verify
3. By–pass valve open.
4. Refrigeration system not
operating.
1. Dryer overloaded (air flow).
2. Heat exchanger clogged.
3. Frozen evaporator coil.
13–8–612 Page 65
REMEDY
1. Verify proper flow and load at dryer
inlet.
2. Follow instructions in manual
checking and setting hot gas by–
pass valve.
3. Verify ambient conditions as
specified in the manual.
1. Verify proper flow and load at dryer
inlet.
2. Check fan operation. Verify proper
operation of fan cycling control.
3. Follow instructions in manual for
checking and setting hot gas
by–pass valve.
4. Check unit for leaks using soap
bubbles or electronic leak
detector. Repair leak.
5. Check fan operation. Verify proper
operation of fan cycling control.
1. Verify proper flow and load at dryer
inlet.
proper operation. Follow instruc–
tions in maintenance manual.
3. Close by–pass.
4. See "Dryer not running, Motor light
is on" and "Dryer not running,
Motor light is off," page 64.
1. Verify proper flow and load at dryer
inlet.
2. Clean exchanger to remove debris
and restart unit.
3. Verify proper load and hot gas by–
pass valve settings. Follow instruc–
tions in manual to check and set
hot gas by–pass valve.