38
SAFIR 5L
OPERATION AND ATTENDANCE MANUAL
PG 01-31
4.8.9.
Flushing of the Oil Pump Relief Valve
If foreign matter gets under the seat of the relief valve or between the piston and the regulation casing,
81130.01 oil pump does not deliver the required oil pressure to the APU. It is necessary to flush the relief valve
according to the procedure described below either directly on the APU without dismounting of the oil pump
(according to Article 4.8.9.1), or on a dismounted oil pump - i.e. outside the APU (according to Article 4.8.9.2).
(The description is related to Fig. 9)
4.8.9.1.
Flush the relief valve without dismounting the pump from the APU:
a)
Dismount the suction piping from the oil pump;
b)
Unseal and screw off four bolts (5);
Dismantle the cap (6) with adjusting screw (7), and bolts(5) with washers (8)
Remove spring support (3), spring (2) and piston (4), and concurrently check, if the piston does not rub in
the regulation casing and the spring is floating on the piston and spring support.
Wash the removed component parts and rinse regulation casing with clean petrol.
Mount the removed component parts back into the pump, lock the screws by binding wire and seal the
cap (6)
c)
Mount the suction piping on the pump and secure it with binding wire.
Before APU actuation, perform the actuation preparation according to the Instructions for Operation;
After 5 minutes of APU operation, check the oil pressure behind the pump, which must reach the
following values for the individual modes:
idling min. 170± 10 kPa
100 % min 210± 10 kPa
The measuring of pressure is performed using test piping with pressure gauge, which is mounted in place of the
piping between the oil pump and the oil filter.
d)
Record the flushing of the oil pump into the oil pump certificate and into the APU Engine log book.
4.8.9.2.
Flush the relief valve with dismounting the oil pump from the APU:
a)
Dismount the pump from the APU. The dismounting will be performed by unsealing and screwing off four
bolts and unscrewing the input and output piping;
b)
Unseal and screw off four bolts (9), detach the plug (10).
c)
Flush the seat of the relief valve so that the piston (4) in the casing gets pressed in the axial direction to release
the foreign matter in the seat of the relief valve. Concurrently rinse the seat with clean petrol, while the pump
is tilted into such position, so that any foreign matter can rinse out. Be careful during the flushing, so that the
seat of the relief valve would not get damaged.
d)
After the flush, mount back the removed parts, secure the bolts with binding wire and seal them.
e)
Mount the oil pump back on the producer, secure the bolts holding the pump with binding wire and seal them.
Connect the input and output piping and secure it with binding wire.
f)
Before the APU actuation perform the actuation preparation according to the Instructions for Operation. Check
the oil pressure according to Article 4.8.9.1;
g)
If the defect of the pump is not corrected by this procedure, it is necessary to perform the flush of the relief
valve according to Article 4.8.9.1;
h)
Record the flush into the certificate of the oil pump and to the APU Engine log book.
NOTE:
When flashing and handling the oil pump parts, you must be careful not to damage them, namely
the seat of the relief valve and the piston.
The listed work can be performed by a serviceman or by an authorized specialist of the user.