stertil SP Series - Insufficient Deck Elevation; Lip Extension Problems; Premature Lip Extension; Deck Lowering Issues

Operation Manual (Version: B) 39 Type SP
7.1.2 The deck does not rise (sufficiently) even though the motor is
running.
Cause Solution
There is a load on the deck. Remove the load from the deck.
There is an obstruction. Remove the obstruction.
Other cause. Contact your local service department.
7.1.3 The lip of the dock leveller does not (sufficiently) extend.
Cause Solution
There is an obstruction. Remove the obstruction.
The optional BDC is (still) switched on.
The lip does not extend completely.
Switch off BDC.
Other cause. Contact your local service department.
7.1.4 The lip is extended before the deck rises.
Cause Solution
There is a load on the deck. Remove the load from the deck.
There is an obstruction. Remove the obstruction.
Other cause. Contact your local service department.
7.1.5 The deck does not descend or does not descend sufficiently.
Cause Solution
There is an obstruction. Remove the obstruction.
The safety valve in the main cylinder is
blocked.
Briefly press [deck up] one or more
times.
Other cause. Contact your local service department.