Manitowoc 2250 Service And Maintenance Manual

Reference Only
HYDRAULIC AND AIR SYSTEMS 2250 SERVICE/MAINTENANCE MANUAL
2-36
Published 11-06-15, Control # 040-13
Table 2-14 Air Dryer Troubleshooting
Trouble Probable Cause Remedy
A. Unloader valve
discharges too long.
Faulty check valve (in air dryer).
Discharge should last only a few seconds. A
faulty check valve allows a longer discharge
period and compressor cycles constantly (30
to 50 seconds between cut-in and cut-out).
Replace check valve.
B. Air dryer unloader valve
does not discharge
when compressor
cuts-out.
Faulty unloader valve. Repair or replace air dryer unloader valve.
Faulty heater (moisture freezing in unloader
valve).
Replace faulty heater.
C. Air dryer unloader valve
does not close when
compressor cuts-in (air
system pressure does
not rise to normal
operating range).
Faulty compressor unloader valve, or faulty
air dryer unloader valve.
Perform the following check:
Disconnect pilot line at air dryer unloader
valve. If air dryer unloader valve closes,
compressor unloader valve is faulty. If air
dryer unloader valve remains open, it is
faulty.
Repair or replace faulty unloader valve.
D. Air system pressure
does not rise to normal
operating range.
Strainer plates and filter plugged with dirt
and oil.
Clean (see Maintenance).
CAUTION
If it is necessary to operate crane before air dryer
unloader valve can be replaced due to Trouble B,
manually drain air dryer several times daily,
otherwise water level will rise in sump, possibly
damaging air dryer baffle.
CAUTION
If it is necessary to operate crane before air dryer
unloader valve can be replaced due to Trouble C,
install “Emergency Pipe Plug” (Figure 2-37
) in
discharge hole of faulty unloader valve. Manually
drain air dryer several times daily, or water level will
rise in sump, possibly damaging air dryer baffle.
FIGURE 2-37
P302P303
1
2
3
4
5
6
8
7
9
10
12
11
7
Item Description Item Description
1 Air Dryer Unloader Valve 7 Spring
2 Emergency Pipe Plug (installed) 8 Filter
3 Manual Drain Valve 9 Bolts
4 Heater 10 Check Valve
5 Emergency Pipe Plug (stored) 11 Head
6 Body 12 Strainer Plates

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English