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AC Gauge Port
I just want to make sure I’m not misunderstanding something…
In the OTR condenser bay, there is a black tank (accumulator I assume?), about a gallon volume maybe. On the side towards the rear of the bus, there is a valve like the ones on the 05G compressor. It has a square head that you can use to front or rear seat the valve to isolate parts of the system. That fitting also has a gauge port. After evacuating the refrigerant, I noticed that this area has an oily residue. I removed the cap on the gauge port and discovered that there is no valve stem or check valve inside. I’m not really sure what could have happened to it, but it’s not there. So I assume this needs to be replaced, right?
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15 Replies
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Here is what mine looks like. I hope this helps?
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See pages 2199 thru 2201 in the “Parts” manual for your bus.
Notice it takes 2 of the service valve assembly, item #4, part# 950228.
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The illustrations in the parts manual just show it with the cap on. Thanks for the part number.
I just can’t imagine why that valve stem or check valve wouldn’t be in the port… So only the plastic cap was holding the refrigerant in… or at least trying to as evident by the oily residue.
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I could be wrong, but it looks like the silver caps are covering the valve stem that allow you to isolate the port or to open it to the system. This is the way my Cruisairs are done.
Rick
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BDuplan:
Contact me at 2-ten-8-six-1-four-1-one-eight. And I’ll explain what is what.
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Thanks Don, I’ll give you a call a little later.
Maybe it’s not a gauge port but just a port to add refrigerant and that isolation valve should remain back-seated unless you have a tank hooked up. Either way, it’s leaking and needs replaced.
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Rick, you are correct, there is a valve under that cap that you can operate with a 1/4″ wrench or square-drive socket. I am just surprised that the port on the top (under the black plastic cap) does not have a spring-loaded valve stem/check ball in it as the gauge ports on the compressor do.
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BDuplan:
The plastic cap is not there to keep the freon in. The plastic cap is to keep debris out. Under that plastic cap is a normal R134a service valve with a schreider/check valve, like at the compressor, and on our daily drivers since 1995.
Maybe the service valve is not back seated (closed), or it leaking when its closed, allowing pressure at the schreider/check valve that is also leaking?
Service valve Prevost part# is 950228.
Because I don’t have the equipment to force 24 Lbs of R134a into the system, I service my OTR system at the R134a fittings on the O5G compressor and let it suck it in.
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Does anyone have an alternate source for this 950228? Prevost is showing only one available. I’m wondering if I can get by with an NPT to JIC 90* fitting for the time being until the parts become available and fill at the compressor as Don said.
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Mobil Climate Control https://www.mcc-hvac.com/?cont=NA
For a dealer see the map at the bottom of their home page.
Here’s their parts manual: https://www.mcc-hvac.com/wp-content/uploads/2014/11/T-370PL.pdf
See page 23
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Thanks! York PA is a short drive from us!
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Those valve should be shipping out later this week. In the meantime I bought a tank of nitrogen and put 50 psi in the system to check for leaks with Nu Blue solution. An ultrasonic leak detector didn’t find any leaks, even where I knew there was one. Both sight glasses on the accumulator are leaking at the threads. I’ll pick up some sealant and remove/clean/reinstall the sight glasses and then hope it holds pressure. I’m really hoping there’s not another leak buried somewhere.
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To find the leaks you need to pressurize to 250 psi or better.
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Mikee, do you use a welding regulator to pressurize the system? I don’t know if I can get 250 psi in through a regulator based on the way it works, and I don’t have the fittings to go from the tank straight to an R134a fitting. Once there is pressure on the outlet port of the regulator, it tries to start closing the poppet valve. I didn’t try cranking it all the way in, but I’ll give it a shot.
I repaired the leaks at the sight glasses and found a couple more at the compressor’s pressure sensors (I had been into the compressor previously.) I got those sealed up and let it sit overnight. It dropped from 50 psi at ~90F to 44.5 psi at ~70F. Ideal Gas Law says it should have been closer to 47F, which is about what was in the lineset before I opened the Schrader valve on the suction port. I’ll crank up the pressure today and see if I can locate the remaining leak(s). We are leaving tomorrow so I really hope I can get it working and not have to rely on the Cruise Airs going down the road…
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I use a gas regulator that goes to 400 psi. The outlet port has the correct fitting for the system. Easy to do, just remove the outlet fitting and use what you need or you can make a hose to connect to what is there now.
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