Theory of Operation
PROPEL-BOOM DOWN SELECTOR VALVE OPERATION
However, in a propel and boom down combined
The function of propel-boom down selector valve (I) is
operations front pump supply oil is blocked by the right
to route the pilot controller pressure signal (F) to shift
propel valve (E) and does not flow to the boom I valve
the boom II valve (A) also when the combined propel
(B). To get supply oil to the rod end of boom cylinders,
and boom down functions are actuated.
the boom II valve (A) is shifted to route rear pump (H)
supply oil to the cylinders. When the right propel valve
When just the boom down function is actuated, the
(E) is actuated, the propel pilot pressure signal (D)
pilot controller pressure signal (F) flows to the pilot cap
increases shifting the propel-boom down selector valve
to shift the boom I valve only. Pilot oil to the boom II
spool (C). The pilot controller pressure signal can now
valve is blocked by the propel-boom down selector
flow through the selector valve and shift the boom II
valve spool (C). Front pump supply oil flows through
the right propel valve (E) neutral passage to the boom
I valve and out to the rod end of boom cylinders.
The return oil from the head end of boom cylinders still
Return oil from the head end flows through the boom I
flows through the boom I valve to return.
valve to return.