Vetus OB175 Instructions D'installation page 9

Oil Expansion Tank
A part of the manual steering pump should serve as an oil
expansion tank. The expansion space required depends on the
quantity of oil in the steering system and the expected minimum
and maximum ambient temperatures.
If the expansion space is too small, oil will escape via the air
relief hole in the filler cap of the top steering pump.
So, install an extra oil expansion tank when:
- A steering system consists of two manual steering pumps
and an electro-hydraulic pump.
- The total length of the piping is very large.
- Very considerable temperature changes are expected during
operation.
- An extra oil expansion tank is also recommended if it is
expected that the boat will undergo violent movement during
operation.
Furthermore, an extra oil expansion tank simplifies filling the
system and checking the oil level.
Fit the oil expansion tank above the (top) steering pump.
Seal closed the air relief hole in the filler cap of the top steering
pump.
Connect the oil expansion tank to the steering pump's top con-
necting pipe using a hose and a hose pillar.
N.B.: This section of the steering system has virtually no pres-
sure (the pressure is related to the height of the fluid column
between the expansion tank and the steering pump).
The Vetus oil expansion tank cap has an air relief hole; when fit-
ting another tank, ensure that this air relief is present.
Connections
Never use Teflon tape for sealing the screw connections; the
use of a fluid sealant should be done with great care; problems
could be created if any sealant enters the hydraulic system.
Steering Pump:
Steering pump
(lower)
The pipe connections for the cylinder are already fitted.
If a balance pipe has to be connected, the connectors (G 1/4)
should be fitted with aluminium or copper sealing washers.
Cylinder:
The pipe connections for the steering pump are already fitted.
Hydraulic Steering Systems OB175, OB300
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Installing the Hoses
The separate parts of the hydraulic steering system are con-
nected together with nylon hose (8 mm. (0.31") internal, 12 mm.
(0.47") external diameter).
Hydraulic Steering with Double Operation:
Connect the hoses from both pumps to the cylinder using T-
pieces.
Consult Diagrams '1', '2', '3', '4'.
To reduce internal resistance always keep the connecting hoses
as short as possible.
With reference to bleeding the system, it is recommended that
the horizontal hose sections should be fitted with a slope of
3 cm. per metre (3/8" per ft); the pump side higher than the
cylinder side.
Install the hoses in such a way that the risk of external damage
or attack by chemicals or high temperature is reduced to a min-
imum.
Protect hoses which pass through a bulkhead with grommets or
use bulkhead couplings.
Bends must be absolutely free of kinks; any kink in the system
restricts the free flow of the hydraulic oil.
After installation, blow through the hoses with nitrogen, or com-
pressed air, for example, (never use water!) to check for any
blockages and remove any pollutants.
The minimum bend radius for the nylon hose is 90 mm (3.5").
Always fit the hose with brackets; distance between brackets
about 60 cm.
The hose is shortened by
cutting.
Never cut the hose with a
saw (sawdust
hydraulic system will cre-
ate problems) or by clip-
ping (this deforms the
hose).
Steering pump
(upper)
ENGLISH
in the
7
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