15
Fault Possible
Cause
Remedy
The vacuum pump does not reach the
usual pressure
The drive motor draws a too high current
(compare with initial value after
commissioning)
Evacuation of the system takes too long
The vacuum system or suction line is not leak-tight
Check the hose or pipe connections for possible leak
If installed with vacuum release valve/regulating
system, vacuum release valve/regulating system is
faulty or damaged
Adjust, repair or replace parts
Contaminated oil (the most common cause)
Drain the oil
(see “Maintenance” in page 8)
No or not enough oil in the reservoir
Top up oil
(see “Maintenance”in page 8)
The exhaust filters (120) are partly clogged
Replace the exhaust filters (120)
(see “Maintenance”in page 8)
The oil filter(100) is partly clogged
(the oil flows through the bypass only, the oil does
not get filtered any more)
Replace the oil filter (100)
(see “Maintenance”in page 8)
Mesh screen (261) on the suction connection (260)
is partly clogged
Clean the mesh screen (261)
If cleaning is required too frequently install a filter
upstream
In case an inlet filter is installed on the suction
connection (260):
The filter on the suction connection (260) is partly
clogged
Clean or replace the inlet filter, respectively
Partial clogging in the suction, discharge or
pressure line
Remove the clogging
Long suction, discharge or pressure line with too
small diameter
Use larger diameter
The valve disk of the inlet non-return valve is stuck
in closed or partially open position
Disassemble the inlet valve, clean the mesh screen (261)
and the valve (257) as required and reassemble
The oil tubing is defective or leaking
The oil return pipe (195) is broken
Tighten the connections
Replace the connections and/or the tubing (replace with
identically dimensioned parts only)
Version with float valve (200) and oil return pipe:
float ball of float valve (200) stuck at the outlet
Roll the float valve (200); replace it when necessary
(Check float valve in page 10)
A shaft seal is leaking
Replace the shaft sealing ring (Greenco service)
The exhaust valve (159) is not properly
seated or stuck in partially open position
Disassemble and reassemble the exhaust valve(159)
(Greenco service)
A vane(22) is blocked in the rotor or otherwise
damaged
Free the vanes (22) or replace with new ones (Greenco
service)
The radial clearance between the rotor (14) and the
cylinder (1) is no longer adequate
Readjust the vacuum pump (Greenco service)
Internal parts worn or damaged
Repair the vacuum pump (Greenco service)
The gas conveyed by the vacuum pump
smells displeasing
Process components evaporating under vacuum
readily volatile and thus gaseous components of
the oil, particularly right after an oil change.
Check the process, if applicable
Use a different type of oil, if applicable
Oil (Maintenance in page 8)
Oil not changed for a long time
Replace oil, including cleaning and replacing oil filter
(Maintenance in page 8)
Clogged exhaust filter (120) and oil turning black
Flush pump
Replace oil filter (100)
Replace exhaust filter (120)
Fill in fresh oil (Maintenance in page 8)
If the service life of oil is short, use oil of desirable
