still very important responsibilities. The procedures for
methods you can use to identify failure of these
cleaning and lubricating CPP pump couplings are the
same as those we described earlier in this chapter for the
MAIN RELIEF VALVE. A faulty main relief
FO and LO pump couplings.
valve can be identified by a low-pressure alarm at the
console, but the actual answers can be found at the
Alignments and Adjustments
HOPM. This component failure can be easily identified
by the operator. The operator simply looks at the HOPM
pressure gauges and notes that all pressures are
You will routinely make alignments and
extremely low or nonexistent.
adjustments to couplings and other components. You
will usually perform these tasks after you have cleaned
SEQUENCING VALVE. You may suspect that a
and lubricated the components. Alignments and
sequencing valve is faulty by detecting a loss of pitch
control as well as a loss of hydraulic oil pressure,
adjustments are either scheduled or conditional. During
depending on how the valve fails. For instance, if the
the cleaning process, for example, you may discover that
valve fails in the open position, then all the oil would
a coupling requires an alignment check or adjustment.
become high-pressure oil and the low-pressure alarm
To Perform an alignment check you can follow the same
would not sound. In this case, the auxiliary servo supply
guidelines you would use for checking the alignment of
(control oil) pressure would be drastically low and
a FO or LO pump. These guidelines were described
system control would fade. On the other hand, if the
earlier in this chapter.
sequencing valve were to fail in the closed position, a
low-pressure alarm would sound and alert the operator.
The CPP system is one of the few systems that you
In this instance, the operator would also be able to see
as a technician will be required to check for proper
an extremely sluggish pitch response time.
operating pressures. You will also be required to make
some of the necessary mechanical adjustments. You will
MAJOR LEAK. A major leak can provide the
periodically perform these procedures through your
same symptoms as a loss of hydraulic oil pressure,
ship's PMS. Remember, you must first monitor the
depending on the location of the leak.
operation of the CPP system as a whole, and then isolate
We have just told you about some of the components
individual components (one at a time) to ensure they are
you should check for failure when you detect a loss of
functioning properly. Let's take a look at some of the
pitch control or a loss of hydraulic oil pressure. Now,
components you may be required to adjust and the
let's talk about some of the most common maintenance
functions they are designed to perform when the system
procedures you will be expected to perform.
is operating properly.
Cleaning and Lubrication
UNLOADING VALVE. The unloading valve
unloads the pressure of the attached pump back to the
sump if the electric pump is operating and functioning
Cleaning is an continuous task. As a GS, you are
likely already aware that good housekeeping practices
must be maintained at all times. Your responsibilities for
SEQUENCING VALVE. The sequencing valve
cleaning and lubricating the components of the
serves two purposes: (1) It maintains a back pressure
CRP/CPPsystems are very similar to those we discussed
on the system to ensure that a minimum of 400 psi is
for the MRG LO system. This is because the majority
supplied to the inlet side of the reducing valve, and
of the components that require cleaning in both the
(2) it provides high-pressure oil to the OD box.
MRG LO system and the CRP/CPP systems are valves.
In cleaning the valves of the CRP/CPP systems, you
REDUCING VALVE. The reducing valve
must pay close attention to detail. This is because most
provides control oil to the OD box.
of the valves and piping of the CRP/CPP systems are
AUXILIARY SERVO RELIEF VALVE. The
located in the bilge area. Being in this area, these valves
auxiliary servo relief valve relieves excess control oil
are constantly exposed to corrosive elements.
pressure back to the sump.
Other components that require cleaning and
MAIN RELIEF VALVE. The main relief valve
lubrication are the two CPP pump couplings. Even
relieves excessive pump pressure, either from the
though the couplings are not cleaned and lubricated as
electric pump or attached pump, back to the sump.
frequently as the valves, cleaning and lubricating are