D860MGB rev04
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If there are losses in the valve, pressure decreases rapidly, more than 5/6 bar during the first 3/4
minutes and goes on decreasing up to the static pressure value;
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The valve components which can be involved in possible losses are the following:
a)
Hand pump.
The hand pump sealing is assured by a ball. Activate the hand pump, leave the lever against the valve and
wait for some minutes to check the sealing. In case of losses, the lever goes back automatically.
Repeat the test for some times to be sure that the loss is not caused by dirt particles laying between seat
and ball. If necessary, replace the hand pump.
Figure 19 - Part of the valve remaining under pressure when the installation is still (in black)
b)
Hand emergency valve VEM.
The sealing of the hand pump is also assured by a ball whose working can be jeopardized by dirt laying
between seat and ball. Carry out a first check by removing the moving half-cover of the tank and look under
the valve. Every time the emergency button is activated, an oil outflow will be noted.
This outflow has to stop when the button is left. In case this does not happen, there can be losses from the
emergency valves or losses from the electro-valve EVD which has the same discharge point.
The following checks must be carried out with pressure inside the valve. It shall be therefore
necessary to act with due caution. In order to check the sealing of the emergency valve (see Figure 20), it
will be necessary to remove the coil, unscrew the mechanical part of the coil, remove the pin, carefully dry
the residual oil left inside the seat and make sure that no other oil leaks out.
If oil losses are noticed it shall be necessary to replace the whole downward travel block or carry out a
repair as described as follows.
