Takeuchi TB175W, Руководство по ремонту

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III-64 TB175W
Performance Inspection – Engine Running
The purpose of visual and electrical inspection is to detect obvious problems and
assure AC system function for an accurate performance inspection. If you do the
performance inspection first, you could be mislead. Problem areas discovered
during the performance inspection can give you false clues or symptoms, and re-
sult in repair errors and come-backs. The following performance inspection pro-
cedures are explained in more detail below:
1. Inspect System Component Cycling and
Cab Temperature Levels
2. Check Clutch Cycling Under Load
3. Check Sight Glass
The performance inspection does not cover pressure and temperature sensitive
safety devices (cutout switches, fan control, Trinary etc.). Testing these devices
requires the use of the manifold gauge set for observation of internal system pres-
sures during tests. These are explained in
Chapter 8.
Use the following procedures as a general rule in a performance inspection:
1. Inspect System Component Cycling and Cab
Temperature Levels
A. Turn On the Engine and Air Conditioner – Inspect for system
component cycling and cab temperature levels.
Note: System performance testing will be much faster if all
doors and windows in the cab are closed.
The cab air must cool down to thermostat control setting
levels before system components will cycle on and off, indi-
cating correct function. This is called ‘stabilizing the system’
and takes about five minutes of operation. In very hot weather
the system may not cycle.
B. Check Thermometer Readings
– In the cab you can use your ther-
mometer to measure air temperature at the vents. When the evaporator
is easy to reach with a thermometer probe without removing some of
the dash or duct work, use the probe to measure evaporator tempera-
ture. When the AC unit is on and working correctly, you can see the
thermometer dial needle move down to about 32 degrees, then rise six
to ten degrees and move back down again. The movement up and down
indicates that the cycling clutch and thermostat, or orifice tube and ac -
cumulator pressure switch (to the clutch) are functioning correctly. In
systems with a non-cycling clutch, this movement indicates correct
function of the refrigerant metering device.
The needle movement is called “temperature swing.” When you can
adjust the thermostat setting, the range of swing should change. For ex-
ample, from full cooling (cold) to moderate (between cold and warm),
the swing may change from 32-38 to 32-42 degrees.
Electrical System Inspection