Manitowoc 2250 Service And Maintenance Manual

Reference Only
Manitowoc Published 11-06-15, Control # 040-13 2-31
2250 SERVICE/MAINTENANCE MANUAL HYDRAULIC AND AIR SYSTEMS
2
AIR DRYER MAINTENANCE (CURRENT
PRODUCTION)
Description
The air dryer is a filtering unit that cleans and dries the air
delivered to the air system by the air compressor.
The air dryer consists of a desiccant cartridge and a die cast
aluminum end cover secured to a cylindrical steel outer shell.
The end cover contains a check valve, a safety valve, three
threaded air connections, and the purge valve. The
desiccant cartridge and discharge check valve are screw in
type. Servicing of the screw-in desiccant cartridge requires
removal of air dryer from the crane.
Operation and Leak Test
1. Test the outlet port check valve by building the air
system to governor cut-out and observing a test air
gauge installed on the reservoir. A rapid loss of pressure
could indicate a failed outlet port check valve. This can
be confirmed by bleeding the system down, removing
the check valve from the end cover, subject air pressure
to the unit and apply a soap solution to the check valve
side. Leakage should not exceed a
1 inch bubble in one
second.
2. Check for excessive leakage around the purge valve.
With the compressor in loaded mode (compressing air),
apply a soap solution to the purge valve housing
exhaust port and observe that leakage does not exceed
a 1 inch bubble in one second. If the leakage exceeds
the maximum specified, service purge valve.
3. Close all reservoir drain cocks. Build up system
pressure to governor cut-out and note that air dryer
purges with an audible escape of air. Fan the service
brakes to reduce system air pressure to governor cut-in.
System once again builds to full pressure and is followed
by an purge cycle.
4. Check the operation of the safety valve by pulling the
exposed stem while the compressor is loaded
(compressing air). There must be an exhaust of air while
the stem is held and the valve should re-seat when the
stem is released.
5.
Check all lines and fittings leading to and from the air dryer
for leakage and integrity.
6. Check the operation of the end cover heater and
thermostat during cold weather operation as follows:
7. Electric Power to the Dryer:
With the ignition or engine kill switch in the ON position,
check for voltage to the heater and thermostat using a
voltmeter or test light.
Unplug the electrical connector at the air dryer and place
the test leads on each of the pins of the male connector.
If there is no voltage, look for a blown fuse, broken wires,
or corrosion in the crane wiring harness. Check to see if
a good ground path exists.
8. Thermostat and Heater Operation:
Turn off the ignition switch and cool the end cover to
below 40°F (4°C). Using an ohmmeter, check the
resistance between the electrical pins in the female
connector. The resistance should be 1.5 to 3.0 ohms for
the 12 volt heater and 6.8 to 9.0 ohms for the 24 volt
heater.
Warm the end cover to over 90°F (32°C)and again
check the resistance. The resistance should exceed
1000 ohms. If the resistance values obtained are within
the stated limits, the thermostat and heater is operating
properly. If the resistance values obtained are outside
the stated limits, replace the purge valve housing, which
includes the heater and thermostat.
Disassembly
See Figure 2-34 for the following procedure.
1. Park the crane on a level surface and prevent movement
by means other than the brakes.
2. Drain all reservoirs to 0 psi (0 kPa).
3. Identify and disconnect the three air lines from the end
cover and note the position of end cover ports relative to
the crane.
4. Unplug wiring harness from the heater and thermostat
connector on the purge valve housing.
5.
Loosen the hex bolt securing the upper mounting strap.
6. Remove, retain and mark the two end cover cap screws
(18), lock nuts (19) and four special washers (17) that
retain the lower mounting bracket to the end cover, also
mark these two holes of the end cover. (These bolts are
longer than the other 6 bolts.)
7. Remove the air dryer from its mounting brackets on the
crane.
NOTE: Several replacement parts and maintenance kits
are available which do not require full disassembly.
The instructions provided with these parts and kits
should be followed.
8. Remove the delivery, check valve (15) and o-ring.
Remove the o-ring from the check valve.

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English