Chapter 7AUXILIARY MACHINERY
other light oils that vaporize easily and that, under
compression, form a highly explosive mixture.
4. Use only the minimum amount and the
proper grade of oil for cylinder lubrication.
5. Secure a compressor immediately if there
is an abnormal rise in the temperature of air
discharge from any stage.
6. Be sure a relief valve is installed between
a compressor and a stop valve, or a check valve
is installed between a compressor and the receiver.
If there is no relief valve and the compressor is
started against a closed valve or a deranged check
valve, the air will not be able to escape and an
explosion will result.
7. Do not leave a compressor station after
starting a compressor, especially a new com-
pressor or one that has been idle for some time,
until you are positive that the control, unloading,
and governing devices are working properly.
8. Do not disconnect any part of a com-
pressor if the system is under pressure. To avoid
serious accidents, the following precautions
should be taken before working on, or removing,
any part of a compressor:
a. Leave all pressure gages open.
b. Be sure the compressor is actually secured
and cannot be started automatically or
c. Be sure the compressor is completely
d. Be sure all valves, including the control
or unloading valves, between the compressor and
the receiver are closed.
9. Operate a compressor at recommended
speeds and maintain proper cooling water circula-
tion to prevent damage from excessive
Drain the circulating water system of a
compressor if it is to remain idle for an extended
period, or if it is to be exposed to freezing
maintenance, and safety regarding auxiliary
boilers in this chapter supplements that given in
Engineman 3 & 2, NAVEDTRA 10541 (current
edition). Detailed information on construction,
operation, and maintenance of auxiliary boilers
must be obtained from the manufacturers
The operation of auxiliary boilers used on
diesel-driven ships is under the supervision of an
ENC or EN1. You should ensure that personnel
charged with the operation and maintenance of
an auxiliary boiler are thoroughly familiar with
the boiler and its associated equipment. Satisfac-
tory operation of the boiler depends on proper
care and maintenance. Specific attention must be
paid to maintaining automatic regulating, control,
and safety devices in proper operating condition.
Failure of these devices may lead to a major
casualty, damage to equipment, and injury to per-
sonnel; therefore, continuous, alert watchstanding
should be maintained while the auxiliary boiler
is in semiautomatic or manual operation. An
operating auxiliary boiler should never be left
Faulty operation of auxiliary boilers is
indicated by various symptoms. These symptoms
may indicate one or more conditions in the boiler.
Each condition must be corrected. Consult the
manufacturers technical manual for detailed
information on troubleshooting a particular
boiler. Knowing the probable causes of a par-
ticular symptom can assist you in correcting any
trouble quickly and efficiently. Some of the
troubles encountered in the operation of auxiliary
boilers and their causes are listed in figure 7-2.
The auxiliary boiler feedwater is exposed to
the same contaminants as the propulsion boiler
feedwater. Auxiliary boilers are generally used for
hotel service loads, and shore water used for
feedwater is usually the prime source of con-
tamination. The shore water may contaminate the
feedwater system by leakage through malfunction-
ing galley mixing valves, laundry equipment, and