WD Catalog 2018

904 / 1003

Chapter 8 – Troubleshooting & Service Procedures
8-4 - -
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 superheat 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
(expansion tube)? If there is a leak, why and how did refrigerant get out of the
system? 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
restriction 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
cooling 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.