Takeuchi Hydraulic Excavator TB175W (S/N 17540001~). WORKSHOP MANUAL

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

III-65

TB175W

These readings at the vents will be higher and temperature swing slow-
er  and  not  as  obvious. Also  blower  speed  will  cause  the  temperature,
levels  to  read  higher  (high  air  speed)  or  lower  (low  air  speed)  at  the
same  thermostat  setting.  When  you  measure  air  temperature,  an  elec-
tronic  thermometer/pyrometer  is  a  great  tool  to  have.  You  can  easily
measure cab air temperature at several locations quickly.

Swing temperatures vary depending on where you measure tem-

perature, and on outside temperature, humidity and altitude. The chart
in Figure 7-6, shows some examples of typical temperature variables.
Don’t forget that cab and sleeper area temperatures can vary within the
same vehicle. Also, electronic controls used in newer HVAC systems
often keep the temperature spread within a narrower range.

2. Check Clutch Cycling Under Load

The following operating inspections, visual and by feel, are done outside the
cab while you wait for the system to stabilize.

A. Lift hood – With the hood up (or cab tilted) observe the clutch cy-
cling under load.

Note: If the condenser is hood mounted you may not have adequate

air flow through it.

B. Touch suction and discharge lines – Soon after system start up you
can safely feel the suction and discharge lines and note their change in
temperature. The discharge line will get hot (after a while it may be to
hot to touch) and the suction line will get cooler.

3. Check Sight Glass

The sight glass is the only point where you can actually see inside the air
conditioner during operation. Check the sight glass through the window on
the top of the receiver-drier (or the separate in-line sight glass). If the sys-
tem is functioning properly and cooling the cab adequately, the sight glass
should be clear (you will not see anything in it). If it is not clear when the

system is first turned on, wait a few minutes for the system to stabilize, then

look again. Figure 7-7 illustrates and explains what you may observe in the
sight glass. Roof mounted condenser fans may run continuously or cycle on
and off. If you can’t tell by sound you may have to climb a ladder and ob-
serve the fan blades.

Inspection & Maintenance

Figure 7-6

The chart of AC system and
cab temperature range shows
you typical variables.

AIr tEMp.

dEgrEES f.

AIr quAlIty

CEntEr OutlEt

AIr tEMp.

dEgrEES f.

OutlEt AIr tEMp.

rAngE dEgrEES f.

huMId

70°

80°

90°

100°

dry

43°

47°

lEfT & RIghT AIR OUTlET TEMPERATURE wIll VARY

40°

41°

lEft

rIght

lEft

rIght

lEft

rIght

lEft

rIght

huMId

dry

huMId

dry

huMId

dry

40°

44°

48°

40°

44°

47°

51°

40°

44°

52°

56°

41°

45°

41°

44°

41°

45°

43°

47°

46°

52°

47°

54°

48°

55°

50°

56°

III-66

TB175W

Note: A roof mounted condenser or AC unit assembly often in-

cludes a roof mounted receiver-drier (and sight glass) close to
the condenser.

Heater System Inspection

A heater system inspection is really a combination engine cooling system and
heater inspection. All heater/cooling system rubber parts deteriorate due to the
air (ozone), heat, coolant and oils. They should be replaced at regular intervals to
prevent breakdown on the road. Metal parts and gaskets are subject to malfunc-
tion or breakdown due to fatigue and corrosion.

Coolant has a limited life and should be replaced regularly. If it is dirty, the

cooling system should be drained and flushed or back flushed (using special

equipment) before refilling with clean water and anti-freeze. Coolant must be hot

when using the hydrometer to check protection (freeze-up) level. The following
inspection procedures are explained in more detail below:

1. Check Heater Control Valve Function

2. Inspect Other Functions

1. Check Heater Control Valve Function

Many air conditioner/heater systems depend on the heater control valve for
temperature control and positive closure. You can easily check heater con-
trol valve function as follows.

A. Cool engine – Start with the engine cool, set the temperature to cold
and leave the fan off. As the engine warms up, feel the heater return
hose. If the hose feels warm or hot, the heater control valve is leaking
internally. This type of leak can seriously reduce air conditioning per-
formance.

performance Inspection

Figure 7-7

These drawings illustrate
conditions you may observe
in the sight glass window.

III-67

TB175W

B. Warm up engine – Next, let the engine warm up to normal operat-
ing temperature and set both fan and temperature on high. Feel both
heater supply and return hoses. If there is a noticeable difference in

their temperature, it indicates a low flow of coolant through the heater

core (a partially closed or blocked heater control valve). This could re-
sult in poor heating performance during cold weather conditions.

2. Inspect Other Functions

There are some things you can’t see or feel when you inspect the thermostat,
heater core, radiator pressure cap, electrical switch and control valve func-
tions. Some of these can be checked with the pressure and thermostat testers
as described in Chapter 6. A hand pump pressure tester can also be used to
check for coolant leaks. This is done by using the pump to raise the pressure
inside the system above normal operating pressure to force small suspected
leaks to show up.

Heater/cooling electrical and valve component inspection is the same as

air conditioner inspection. The controls are operated to see if they function

correctly to maintain or vary cab temperature and air flow.

Preventive Maintenance Worksheet

Please feel free to modify or copy the worksheet in Figure 7-9. Actual vehicle

use, mileage, operating conditions and maintenance budget may influence service

frequency.

Inspection & Maintenance

Figure 7-8

Heater/cooling system
potential problem areas and
checks are indicated in this
drawing.

III-68

TB175W

Chapter Review

The purpose of these brief inspection procedures is for vehicle system mainte-
nance and to determine if further, more detailed service is required. The uses of

a manifold gauge set, system troubleshooting, recovery, flushing, evacuating and

charging are explained in the next chapter.
  High  usage  and  operating  condition  variations  are  tough  on  air  conditioning
and  heater  components. You  should  establish  and  follow  regular  inspection  and
maintenance procedures to improve overall system function and component ser-
vice life.
  The typical inspection should not take more than 15 to 20 minutes unless com-
ponent  replacement  and/or  complete  system  evacuation  and  recharging  is  war-
ranted. The survey results shown in Figure 7-1, indicate belts, compressor clutch
assembly,  condenser  and  the  refrigerant  lines  are  the  most  frequent  problem  ar-
eas. However, your own experience with service and maintenance may vary from
survey results.

Inspection should first be visual and by feel. Some of your electrical system

inspection will be done as you inspect other components (checking leads, connec-
tions and for loose wires). When you check the electrical circuit, begin with the
engine off but ignition on. A system performance inspection with the engine run-
ning and system on really combines electrical and AC or heater system function.

Chapter review

III-70

TB175W

Troubleshooting
& Service Procedures

• Troubleshooting Overview

• Understanding System Function

• A Troubleshooting Example

• Manifold Gauge Set Installation

• Troubleshooting by Manifold Gauge Set Readings

• Review of Frequent Problem Areas

• Conclusion

Can you fix an air conditioner or heater system without finding and correcting

the cause of the problem? You bet you can!

It happens every day and it’s not good

for business. Here is an example. A truck pulls in off the road and the operator asks
to have his rig serviced in a hurry. He tells you the air conditioner isn’t cooling like
it should and dashes into the restaurant for lunch.

You tip the hood, and check the sight glass on top of the receiver-drier. You see

bubbles, not a lot but a fairly constant stream of them. It is obvious the system is
low on refrigerant so you hook up the manifold gauge set, purge the gauge set hoses
of air, and add refrigerant until the sight glass clears. Then you check evaporator
temperature and it’s OK.

The air conditioner is repaired right?

Wrong! What you

did is add refrigerant and the problem went away. You did not find and fix the cause

of the problem.

Component failure in an air conditioning system may be the result of a problem

elsewhere in the system. For example, a belt or clutch failure might be caused by a

dirty condenser restricting air flow and increasing head pressures. High head pres

sures commonly create problems with other system components.

Take time to look

beyond the obvious for a potential hidden problem

Troubleshooting Overview

Troubleshooting includes collecting enough information to locate the cause of the
problem, then correcting the problem and its cause by replacement, adjustment, and/
or repairing. You begin by gathering information from the most to the least impor-
tant sources.

Starting with the most important:

1. Your personal knowledge and experience with AC systems.
2. The vehicle operator's knowledge and experience—question him or her.
3. The work order.
4. Good test equipment and the HVAC system

The routine you follow when troubleshooting should proceed from the most to least

productive way of locating the problem and fixing the cause.

Click on any of these

subject headings to go

directly to the page

III-71

TB175W

Experienced troubleshooters talk to the operator if they can, then personally verify

the symptoms of the problem whenever possible. They attempt quick fixes on the

basis of their knowledge of common system problems and causes when appropriate.
They know where components are located, and make repairs when they have a good

idea of what the problem is. They fix the cause or causes as well as the problem.

They are confident of their knowledge and ability.

Note:

The best troubleshooters all know who to call when they get

stuck.

They know someone who knows more than they do and

are not too proud to ask for help or suggestions when needed.
The key—understanding system function

The Key–Understanding System Function

Your complete understanding of AC and heater systems and how they work,

plus what can go wrong, is the key to troubleshooting and repair.

We have talked

about components and system function before. Now let’s take a little different ap-
proach in describing what happens when the air conditioner is turned on. In Figure
8-1 we have used numbers on the illustration to track normal air conditioner func-
tion.

Troubleshooting & Service Procedures

Figure 8-1

An illustration of the typical
HVAC system. The numbers
follow the action when the
AC part of the system is
working properly (moving
heat out of the cab and into
the outside air).

III-72

TB175W

When you turn on the air conditioner at the control panel (1), the thermostat (2),
is supposed to sense a warm temperature at the evaporator. A circuit in the ther-

mostat should close, allowing current to flow through the thermostat to the com

pressor clutch field coil (3). When this happens, the clutch field coil becomes an

electromagnet and pulls the clutch drive plate (4) tight against the clutch pulley (5).

Note:

The same AC switch (1) may also turn on the fan or blower

motor (2a) to circulate air in the cab. The air feels warm at

first but will cool quickly.

A belt connects the clutch pulley to a drive pulley (6) on the engine. The engine
provides the power to turn the clutch pulley and drive the compressor (7) when
the clutch is engaged. When operating, the compressor compresses and pushes
refrigerant gas to the condenser (8), through the receiver-drier (9), and to the ex-

pansion valve (10) orifice. When it does, it puts a lot of pressure on the gas. The

compressor raises the temperature and pressure of the refrigerant inside the high
side of the system.

At the same time, the compressor is also sucking in low pressure refrigerant

gas from the expansion valve orifice, evaporator and through the low side of the

system. The movement of the refrigerant inside the system transfers heat energy
from the cab to the outside air for occupant comfort.

The automatic functions of the thermostat (or the pressure valve on some ac-

cumulators), and the expansion valve, help maintain pressures and temperatures

inside the system at safe and efficient operating levels. Pressure and tempera

ture are constantly changing due to compressor and expansion valve action, the
amount of heat energy being moved and the environment or weather conditions.

The engine cooling system fan and clutch (11), and the evaporator blower mo-

tor (2a), move a sufficient amount of air through the condenser and evaporator.

On the road, vehicle speed provides most of the (ram) air required for the con-
denser to work right. In a parked or slow moving vehicle the engine fan (or roof

or remote mounted condenser and fans) moves sufficient air through the condens

er fins.

Note:

Clean refrigerant and refrigeration oil should be inside the

system in the amount specified by the manufacturer. Mois

ture, sludge (moisture combined with refrigerant oil or desic-
cant), or desiccant particles will prevent the correct perfor-
mance of the system and may cause component damage.

A Troubleshooting Example

Remember the story at the beginning of this chapter? The vehicle operator pulled
in off the road and asked you to repair the rig. He was in such a hurry he didn’t
tell you anything except that the air conditioner wasn’t cooling. Here is the best
way to handle that kind of situation.

Understanding System Function

III-73

TB175W

Use your knowledge and experience. Ask yourself what could have caused a lack
of cooling in that rig! Did the compressor drive belt break? Did a pressure switch
or relief valve cutout the compressor because of high or low system pressure?
Does the switch or valve in this type of system reset itself? Could there be a su-
perheat switch and thermal limiter with a melted fuse. Did someone else service
the system recently and put in too much refrigerant?

Could there be contaminants in the system blocking the expansion valve (ex-

pansion tube)? If there is a leak, why and how did refrigerant get out of the sys-
tem? You know if refrigerant can get out, air and moisture may get inside as well,
especially if the leak is on the suction side of the system. Could there be a restric-

tion to refrigerant flow in one of the high pressure lines because of a kink? From

your knowledge and experience, you already know about these possibilities and
others when you talk to the operator (before he has the chance to leave).

The right kind of questions can speed up troubleshooting and your service

work by pinpointing the problem(s) that needs fixing. Your conversation with the

operator might be as follows:

• How long ago did the AC system stop cooling?

Answer:

About an hour ago.

• What steps did you take when you noticed the lack of cooling?

Answer:

I put it on maximum cool.

• Then what did you do?

Answer:

When it wouldn’t cool, I opened the window and

turned the air conditioner off.

• Is this problem new or has it happened before, and when?

Answer:

In the last few days I’ve had problems with cool-

ing off and on—this is the first time it’s happened when I was

close to a place that did AC service.

• Do you get any cooling at all?

Answer:

Yes but it seems to quit after a while.

• Do you still get air flow at the vents from the blower?

Answer:

Yes.

• When was your air conditioner checked thoroughly?

Answer:

Before I bought the rig last May (a year ago).

• Has the heater been used recently and did it work OK?

Answer:

Yes.

Troubleshooting & Service Procedures

III-74

TB175W

• Have you had other service problems in the last few months?

Answer:

No.

• (If the answer was yes, you should ask—When? Where?

What was fixed or replaced?).

• Finally, ask the operator if he or she has a wiring diagram for

the system.

Now let’s look at the information you have gathered from the operator and what
you know from experience. He believes the problem is that the AC system quits
cooling after it has been on for a while! You know that the AC system has not
been maintained since the rig was purchased a year ago. Because of that, there
could be several causes for the problem (lack of cooling) and there may be other
potential problems about to develop.

It is possible that some refrigerant has leaked. Moisture and other contamina

tion may be inside the system. You have been told there are no heater problems,
but that doesn’t mean there are none that might affect AC system operation. The
AC system has quit cooling several times in the last few days. The problem may

have become more severe than when it quit cooling the first time.

If enough refrigerant or oil has leaked out, a low pressure cutout switch may

have cut the circuit to the clutch, protecting the compressor. Because the system
has not been maintained in a year, there may be other components that should be

serviced. You could fix the probable causes, and the system might work and then

break down again as the rig drives out of your place. From your knowledge and

what the operator has just told you, you know this may not be a quick fix prob

lem.

It’s up to you to describe the service situation to the operator. Tell him you

need to do a complete system maintenance inspection to find and correct the

problem or other potential problems. He can give you the go ahead for full ser-
vice and repair now, wait till you have inspected the system to determine cause
and cost, or delay repair until he has some down time available.

Normally when the operator can tell you what the problem is, you would first

operate the system to verify the problem. In this situation your troubleshooting (your
own knowledge added to what the operator told you), indicates the next step.

You need to do a complete maintenance inspection instead! Proceed as described

in Chapter 7. Correct any obvious problems and check carefully for leaks. Leak
testing should be visual, by feel and with a leak detector. Next, do your perfor-
mance test with the engine running and the AC system on.

Note:

Don’t forget to check the heater system too! If the water valve

is not closed, then hot engine coolant flowing through the

heater core would warm the air at the same time the evapora-
tor was trying to cool it. The result would be the appearance
of an AC problem.

A Troubleshooting Example

III-75

TB175W

If your AC and heater visual, electrical and leak inspections don’t turn up any
problems, save time by hooking up the manifold gauge set before you make the

performance test. If you find a leak and can correct it easily by tightening a con

nection, do so. But if too much refrigerant leaked out, you may have to add some
refrigerant to the system for an effective performance test. We will get into detail
on troubleshooting with gauges after we explain manifold gauge set installation
and adding refrigerant.

Manifold Gauge Set Installation

Never hook up the gauge set when the engine and air con-
ditioner are running. Be sure all the valves on the manifold
are closed all the way (turn them clockwise). Check the
hose connections on the manifold for tightness.

Locate the low and high side system service fittings and remove their protective

caps. Position or hang the manifold gauge set in a convenient location. Figure 8-2

illustrates a good example of manifold gauge set hookup in one service situation.

The manifold gauge set is a necessary tool in troubleshooting AC system prob-
lems. The following steps are performed during and after installing the manifold
gauge set:

1. Purging Air from the Gauge Set Hoses

2. Adding Refrigerant to the System

3. Stabilizing the AC System.

Troubleshooting & Service Procedures

CAUTION

Figure 8-2

A typical manifold gauge
set hookup is shown in this
illustration. The center hose
on the gauge set is connected
to the vacuum pump.

III-76

TB175W

1. Purging Air From Gauge Set Hoses

Environmental regulations require that all service hoses have a shutoff valve
within 12 inches of the service end. These valves are required to ensure only
a minimal amount of refrigerant is lost to the atmosphere. R-12 gauge set

hoses have a valve near the end of all three hoses. R-134a gauge sets have a

combination quick disconnect and shutoff valve on the high and low sides.
The utility (center) hose also requires a valve.

The initial purging is best accomplished when connected to recovery or

recycle equipment. Figure 8-3 illustrates the gauge set connections for purg

ing and refrigeration recovery.

Note:

The manifold gauges read system pressure when the hand

valves are closed if the hose end valves, and the stem type
service valves (if included) are open.

2. Adding Refrigerant to the System

Now that the gauges are connected, you may need to add some refrigerant to
the AC system before you can do an effective performance inspection. How-
ever, if leaks are obvious they should be repaired prior to adding refrigerant.

Note:

Loss of some refrigerant is not unusual over an extended pe-

riod of time. Adding refrigerant is a typical procedure when
the AC system is maintained on a regular basis.

When adding refrigerant to the system, connect the center hose from the
manifold gauge set to the refrigerant dispensing valve on the container. Fig-
ure 8-4 illustrates this connection.

Manifold Gauge Set Installation

Figure 8-3

The purging setup for mani-
fold gauge set and compres-
sor service valves are shown
here.

III-77

TB175W

Before adding refrigerant to the system you should study the sight glass
while the engine is running and the air conditioner is on. Even if you found
a leak during the system inspection and corrected it, you have no way of
knowing how much refrigerant has leaked. You will not be able to tell how
much refrigerant is in there, but you can see if bubbles are present.

Then check the gauges for unusually high or low readings, or a lack of

pressure. Following this procedure, and using your knowledge and experi-
ence, decide if it is safe and makes sense to add refrigerant in order to make
your full performance inspection.

You are now ready to add refrigerant to the system. For your safety and to

prevent system damage use the following procedure.

Turn on the engine and set the idle at 1200 to 1500 RPM and

then turn on the air conditioner.

Do not open the high pressure hand valve on the manifold
gauge set. The compressor could pump refrigerant into
the container and cause it to BURST. Be sure to keep the
refrigerant container upright to prevent liquid refrigerant
from entering the compressor.

2. Open the refrigerant dispensing valve on the container and then

the low pressure hand valve on the manifold. This allows refrig-
erant to enter the system as a gas on the low pressure or suction
side of the compressor. The compressor will pull refrigerant into
the system.

Troubleshooting & Service Procedures

CAUTION

Figure 8-4

In this illustration we have
noted how refrigerant is
added to the air conditioner.

III-78

TB175W

3. Add refrigerant until the gauges read in the normal range and the

sight glass appears clear. The sight glass may not be clear for a
moment just before or after the clutch cycles on and off but should

generally be clear. Gauge readings will fluctuate as the compres

sor cycles on and off.

Note:

Pressures within the air conditioning system vary with ambient

temperature. A normal pressure range is defined as follows:

Low side

15–30 PSIG

High side

150–280 PSIG

If R-134a is used in place of R-12 the high side readings will

be about 20 PSI higher. For this reason many OEMs are rec

ommending an increase in condenser capacity when retrofit

ting to the new refrigerant, R-134a.

If the gauges show any abnormally high or low pressures as
you are adding refrigerant, stop and investigate for probable
cause. Never add more than one pound of refrigerant. If the
system  is  low  enough  on  refrigerant  to  require  more  than
that amount you should stop and check again for leaks. Then
recover  all  of  the  refrigerant,  repair,  evacuate  and  recharge
the  air  conditioner.  (See  Chapter  9). You  may  want  to  add
dry  nitrogen  gas  to  the AC  system  instead  of  R-12  if  pres-
sures  are  below  normal  and  a  leak  is  suspected.  Nitrogen
gas  is  sold  in  cylinders  under  high  pressure,  1800  to  2000

PSI. Be sure the cylinder has a pressure regulating valve to

control the pressure when dispensing nitrogen gas. Dispose

the gas at no more than 200-250 psi, as this is sufficient

pressure to cause or indicate a leak point. See note under
Troubleshooting by Manifold Gauge Set Readings in this
chapter.

4. When the gauges show normal, close the hand valve on the mani-

fold, the hose end shutoff valve, and the valve on the refrigerant
container. You can now proceed with the performance inspection.

3. Stabilizing The AC System

For reliable gauge readings as an aid in troubleshooting, the AC system must
be stabilized.

Be sure your tools and test equipment are clear of all mov-
ing parts of the engine and air conditioner.

Manifold Gauge Set Installation

CAUTION

III-79

TB175W

Start the engine and set to a fast idle of 1200 to 1500 RPM. Turn on the air

conditioner. After a quick in-cab performance test of control function, blow-

er speeds and air flow, set the AC system controls to maximum cooling and

blower speed on high. All windows must be closed. If cab temperature is hot (rig
has been sitting in the sun with the windows closed), open the windows for
a minute or so to let the hot air out. Run the engine and air conditioner about

five minutes for the system to stabilize. In hot humid weather or where the

AC condenser can’t receive adequate air flow from the engine fan you may

have to use a floor mounted fan to force sufficient air flow through condens

er fins. This helps to stabilize the system by simulating ram air flow found

under normal operating conditions.

When a vehicle has a tilt cab or hood and the condenser is part of the

grill, you must use the floor fan to get air to the condenser. You could tilt the

cab or hood back to normal position, carefully routing the manifold gauge
set and hoses away from moving parts. Then place the gauges so you can
read system pressure.

Troubleshooting by Manifold Gauge Set Readings

The series of figures that follow (Figures 8-6 through 8-15) show gauges with

typical readings indicating AC system problems. Each figure is followed by trou

bleshooting tips, probable causes for the gauge readings shown, and appropriate
service and repair procedures.

Low Refrigerant Charge in the System

Tip:

You see bubbles in the sight glass. The air from vents in
the cab is only slightly cool.

Cause:

Insufficient refrigerant (charge) in the system.

Troubleshooting & Service Procedures

Figure 8-5

Gauge reading, low refriger-
ant charge in the system.

Takeuchi Hydraulic Excavator TB175W (S/N 17540001~). WORKSHOP MANUAL - page 7