Takeuchi TB175W, Руководство по ремонту

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III-92 TB175W
Technicians frequently add refrigerant to a system, replacing refrigerant
seepage through system connections or fittings. If the system has been main -
tained regularly (every three to six months), adding a small amount of re-
frigerant may result in normal system function. However, the best procedure
is to check all connections and look for, find and repair any leaks before
adding refrigerant.
When your leak detector indicates the presence of a leak, you can’t tell
how long the system has been leaking. Finding one leak doesn’t mean there
are not others. Until you have some AC system work experience, it will be
hard to guess how much refrigerant may have leaked. If you have to top a
system off with a half pound of refrigerant or more, adding refrigerant is not
the answer.
Find the leak. Recover all of the refrigerant and repair the system. The
moisture absorbing capacity of any desiccant material is limited and can-
not be measured. For that reason, replace the receiver-drier or accumulator.
Then evacuate the system for an hour and recharge with refrigerant.
When a compressor shaft seal has leaked oil and the refrigerant charge is
a little low, the shaft seal may have leaked because the air conditioner was
not used. The seal can get a little out of round from the weight of the crank-
shaft and leak above the shaft. Running the compressor may cause the seal
to swell and close up the leak. The shaft rotation exerts force all around the
seal and puts life back into it. To prevent this from happening, manufactur-
ers recommend regular AC system operation a minimum of every couple of
weeks even in cool weather.
Keep in mind that the compressor can cause a vacuum inside the system if
there is a restriction in the system. That means it can suck air and moisture
inside under some conditions. It will pull these contaminants in through the
same space where refrigerant and refrigerant oil has leaked out.
Conclusion
What could the air conditioning problem and it’s cause have been at the begin-
ning of this chapter? The operator was in a hurry, but you were able to start your
troubleshooting with the answers he gave you. Problems your inspection may
have turned up are a very low refrigerant charge, a contaminated system or defec-
tive compressor. Those are not quick fix jobs.
On the other hand, you might have found enough debris on the condenser fin
surface to boost high side pressures to an abnormal level during the hottest part of
the day. So the Trinary™ or high pressure switch would cut out from high pres-
sure—but reset itself. You cleaned the condenser, added a half pound of refriger-
ant and AC system pressures and function returned to normal. Service and repair
took a half hour. But there was no way to tell without using your knowledge and
experience. By now you are pretty familiar with AC system problems, the reasons
for some of them, troubleshooting and repair. In Chapter 9 we will describe com-
plete system purging, evacuation, flushing and recharging.
Conclusion