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CC OTR Woes
The compressor clutch on our CC OTR fail. It should have been an easy fix…NOT. I am providing the following information so that others may avoid the problems we had in reaching air conditioning nirvana.
The failed clutch was replaced. It burned up and had a failed bearing. No testing of the electrical circiut or system pressures was performed by the shop.
The replacement clutch burned up in 35 miles! Now the testing began. A relay on the CC HVAC circuit board was “fluttering” and allowing the clutch to short cycle which caused the failure. After a creative work around, it was discovered that the low pressure switch was defective. The replacement low pressure switch was also defective. After replacing the low pressure switch with one from Prevost it was discovered that one of the two condenser fans had failed. The fan being out could result in the head pressure exceeding the limits resulting in shut down and cycling as the pressure falls.
Bottom line, If you have a clutch fail insist that the shop test the electrical circuits activating the clutch and the pressures in the system to determine root cause of the clutch failure. After buying two clutches and much labor, we now have CC OTR air.
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8 Replies
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Good heads up John, thanks for posting.
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John, one of the most important things about the CC OTR is the condensors under the coach.
They stay filthy from road grime and will stop up very quickly. I clean mine almost every trip especially if I have been in the rain. That will make the head pressure climb.
My coach is a 98 so we share alot of the same components. The OTR card in the ECC cabinet down in the first bay can give you trouble leading to problems with the compressor malfunctioning.
I had to solder a wire to work around a burnt trace on the back of the card that would send power the the clutch.
The little traces made on the back of the card that go from point A to B were burnt in have just from age I guess.
All has been well now for about three years.
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Charles;
What do you clean your condensers with?
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Most of the time I use a garden hose sprayer filled with Simple Green degreaser or Greased Lightning.
I have also used a pump up sprayer like you spray weed killer with but it does not have the force the garden hose has.
You can also use a comercial air conditioning coil cleaner. I have some I use at home but haven’t tried it on the bus yet.
Good luck.
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Our OTR card was already patched wth the same wire. I wonder why the trace burned up. Sounds like a common problem.
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Yes, these cards are 14 years old and with the contents of the solder and flux and anything else they used to solder these cards back then lends to corrosion etc.
Nick Hessler tells me he has all the silk screens to make these cards today but trying to get some one to do it and what it would cost is probably out of the question. All the components and drawings are available but it would be some undertaking.
One reason I have considered up grading to a newer coach are these cards.
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I believe the go to guy for serious advice about dealing with CC issues is Miles Circo.
Perhaps someone can provide you with his email address or phone number. As Buddy says right now age is working against a lot of our coaches, and owners have to have a plan for how they will continue to maintain their coach in the future.
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A friend in the electronics business who does the board and system design work says he does short run projects that require circuit boards and there are job shops in the US that will do short run boards. I don’t suspect they are cheap. I think he has also mentioned shops that populate the little do-dads on the boards.
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