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Prevost OTR air charge fittings
What is the industry designation for the charge fittings on the compressor/lines on my 2000 Prevost chassis with “full” OTR Air? I have all the AC charging gauges, hoses, vacuum pump, etc. but the connections on the hoses are the residential R-22 and old automotive R-12 1/4″ or whatever size its called taper seat type. I also have adapters for the quick connect on the new R-134 automotive AC’s. However the big fittings on my coach are like nothing I have encountered so far.
Are they ACME fittings? If so what size? What adapters do I order? I ordered some “ACME AC R134 Brass Adapter Freon Fitting 1/4″ Male to 1/2″ Female w/ valve core”
on Amazon, but upon receipt they obviously are not what I need. The female end is even smaller ID than the male end which looks right for my charge hoses. Either these are the wrong thing, or they sent me the wrong thing vs wat the listing describes.
What do I need to get?
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6 Replies
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On amazon put in these search words “r12 to r134a quick connect” and there will be hundreds of the R12 to R134 quick connect fittings you need. The followinjg are pictures of my setup which is like yours.
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I have those quick connect adapters, they are what my current cars and trucks use. But the fittings on the compressor/lines on the coach are not quick connect, they are threaded and have caps on them that come off and expose threads. I’m a little fuzzy on this because it was a few months ago when I checked them out for possible future maintenance needs to be sure I had the right stuff. I’ll check them again when I get the coach back back on 4 June from Prevost in Fort Worth who is replacing a side window broken by a weed trimmer (not by me).
Found a photo, here is what I have with the cap on it.
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Your not holding your mouth right of something?Yours are like mine, std 134 quik connect. Low side/Blue is the easy to get to fitting, Red/Hi side is the hard to get to back side fitting. They clip/snap on just like your car and truck, no difference. Don’t let the internal threads fool you, they’re for the cap only.
There are o-rings in all the caps, make sure they are there and in good shape and you’ll find you won’t loose as much freon yr to yr.
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Hmmmm, what you are saying and showing makes sense. The low side fitting looks just like mine with the cap on it. I don’t remember taking the cap off the low side fitting when I was checking it out. I remember I took the cap off the high side fitting and I thought it had external threads. Will have to check when I get the coach back. Maybe it was a bad dream.
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I hope you know that the hi/low service ports aren’t active/alive until the king valve next to each is opened by turning it IN/clockwise at least 1 turn. Then, after servicing is complete, they each need to be back seated/closed by turning it out counter clockwise fully. Then put the caps back on the service ports and king valves w/good O-rings.
Another tip: on an hasn’t been run or driven today ambient temperature coach, before you start the engine, take note of the low side pressure reading when you first hook up the gauges. Then look at the R134 chart I posted here in the HVAC area on 5/10/17 to see what it should be in a perfect world. Example: if it’s 70 degrees outside, then pressure should be about 71 psi. If there’s a difference of more that about 5 psi difference high or low you’ll know it’s either under serviced(low), over serviced(high), or about right. -
Stopped by the coach this weekend to say Hi. Another mystery solved. Operator error. My coach does indeed have standard R134 quick connect fittings. The cap I took off a few months ago was the cap covering the access to the king valve shaft. I totally missed the small cap covering the standard R-134 port. It must of been dark or I had my sunglasses on indoors, uuhhmmmgghhh. Or more likely I was just having a stupid moment.
Thanks to Lonestar and others for all the advice. Yes, I am familiar with king valves but for some reason at the moment, maybe because they were in a different configuration than I have worked with before on home ac units, I did not recognize what I was looking at. Here again I invoke the possiblity of a stupid moment.
I do have an Infinicon electronic refrigerant leak detector and offer to help any one local track down a pesky leak that they can not find otherwise. The thing is very sensitive and works great and helped me more than once on home and auto ac issues.
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