Case IH FARMALL 40C, Service Manual

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INTRODUCTION
Safety rules Service precautionary statements climate control
SERVICE PRECAUTIONARY STATEMENTS
Leak Testing
Recharging an air conditioning system that leaks simply allows more refrigerant to escape into the atmosphere and
ultimately leaves the system non-functioning and in need of additional charging.
Therefore, the proper service procedure is to locate and fix any leaks before putting any more refrigerant into the
system.
If a large amount of refrigerant has leaked out, the system pressure will be too low to identify all but the largest leaks.
In this case, partially recharge the system with no more than one pound of refrigerant to check for leaks.
NOTICE: • Any refrigerant introduced into the system for the purpose of finding leaks must also be recovered without
releasing it into the atmosphere.
• Always use the same type of refrigerant for checking leaks as was originally installed into the AC system by the
manufacturer.
• Never use compressed air to detect system leaks. The introduction of air into the system may create a fire or
explosion hazard, may overload the desiccant with moisture, and could contaminate the system with dirt and improper
oil.
All automotive type air conditioning systems leak to some extent. When servicing them it is important that leakage be
minimized. Much of the normal leakage comes from the slow seepage of refrigerant through the flexible hoses. Other
common sources of leaks are at joints between the flexible hose and metal tubing or at threaded hose connections.
These are usually much larger leaks than the natural seepage through the walls of the hose and are almost always
repairable.
Research by the EPA has found that leak detection can be difficult, but existing halogen leak detection systems are
adequate for the major task of finding and repairing leaks causing complaints. Dye stains are not very satisfactory for
finding small leaks.
Newer electronic leak detectors may offer even better leak detection capabilities. However, no single method can find
every leak. Electronic leak detectors may not detect leaks of all refrigerants. For example, older units designed to
detect R12 may not detect
R134
A
. Be sure that the leak detector you use is state-of-the-art and that it is designed to
detect the refrigerant in the system you are servicing.
Service professionals must be extremely diligent in their work to correct all possible leaks. Diligence is essential to
ensure that no small, difficult-to-find leaks go undetected.
Before leaving a job, make one last leak check. Catching a leak just after service will save an inconvenient and
expensive return visit.
Refilling
Refill the air conditioning system using the weight method. The lubricants used in R134a tend to layer onto the walls
of the refrigeration system. This layering obscures the view through the sight glass. Visual methods of refilling R134a
systems will result in improper system charging. For this reason, we do not recommend the old practice of topping
off a partially discharged air conditioning system using the sight glass. The Farmall 40C/50C cab tractors use
700 g
( 25 oz ) of R134
A
refrigerant.
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