BAC Forum
General Boards => Technical Support => Topic started by: Bill Sprague on May 22, 2013, 04:09:07 AM
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My dash air has gradually become less cold. The motorhome is 10 years old with 100,000 miles so I suspect it needs a little boost of refrigerant. I bought a can with a pressure gauge attached that should snap on to a fill port. On our cars it is easy to spot the port. I can't find it on our 2004 Monterey.
Any advice on where to look?
Thanks.
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Bil, alot changed between our Pat and your Monty. Just for the example, ours is under the hood, right of the heater box and lower than the evaperator cylinder. This is from memory but I believe itto be correct.
I seem to recall that the fill vlave is just a schrader valve with a grey cap.
Let e know if this works as we need to do the same thing to ours.
Best
Keith
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Bill,
We will probably have to wait for a fellow Monterey owner with the same year coach to get a exact answer to your question. However I can give you the three most common places that charging ports were installed from the factory.
The first an most logical location is at the compressor, but that was seldom the location selected by the factory. Next is an in line location as the refrigerant lines are leaving the engine compartment. This location is accessible from under the coach. The last and most difficult location to access is under the front cap, by the evaporator case. Unfortunately, the location under the front cap seems to have been the favorite location for the design crew.
Gerald
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Hi Bill
It is up under the front cap. With the generator racked out you will find it about 6 inches up from the edge of the opening toward your left when looking at the coach.
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Thank you Keith, Gerald and Harvey. It is not at the compressor. That's where I expected to be and it is not. I took a quick look up front by the genset and didn't see it. I will take a more serious look there. Today or tomorrow. As Harvey has a 04 Monterery with a Cummins, I suspect we have similar systems.
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First, I admit, until Keith mentioned it in his post, I have never heard of a schrader valve. I Googled it and discovered its similar to an air valve for tires. Since I was under the generator today, I looked to see if I could find an air conditioniing service port. These pictures are the closest thing I found. One is with a rubber cap on, and the other is with it off. For some reason, my iPhone takes crappy pictures. I suspect its the operator.
Is this what Bill is looking for?
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Stan,
No, the picture that you posted was of the electric air compressor for your air leveling system.
Gerald
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I have a 2004 Montery with the Cummins engine.
My refrigerant service ports are very near where refrigerant lines enter the A/C compressor in the engine compartment.
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Hi Bill
It is up under the front cap. With the generator racked out you will find it about 6 inches up from the edge of the opening toward your left when looking at the coach.
It was about 6 inches up but almost in the center, maybe slightly to the passenger side. I bought the refrigerant can with the longest hose because it was on sale. The long hose made it easier.
The can had a built in gauge and instructions. The engine needs to run with the A/C set to full cold on high fan. The quick connector on the can clips to the fill port, you watch the gauge and pull the trigger. When the needle moves to the right range, you quit. The dash air got noticeably colder.
The truth is, I really didn't have to do anything because we are camping with the Schencks. With Marty helping, there was little I had to do! Thank you Marty.
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You are welcome Bill. Thats what Beaver buddies are for. By the way, what three projects are set for today?
Marty
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You are welcome Bill. Thats what Beaver buddies are for. By the way, what three projects are set for today?
Marty
Going for a scenic drive with ice-cream, going out to dinner and having a bonfire!
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Hi Bill,
I'm still looking for it...is this it possibly?
Stan
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Bill: where are you camping? We'll be back north the first week of June( coming down the homestretch!) Maybe when we have pho you can show me how to recharge my a/c.
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Bill: where are you camping? We'll be back north the first week of June( coming down the homestretch!) Maybe when we have pho you can show me how to recharge my a/c.
We are camping at Wine Country RV in Prosser for the long weekend. Is that a pho recharge that's needed? Or, A/C recharge?
I had always thought A/C charging to be some sort of mystical challenge. It was surprisingly easy once Marty found the port.
Bill
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Hi Bill,
I'm still looking for it...is this it possibly?
Stan
Stan,
Mine is 6 or 8 inches above the middle of the genset with it pulled out. I'll try to take a picture today.
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Update:
After finally finding the service ports for the air conditioning on my C-9. I went to O'Relley's and bought the AC Pro that Bill Sprague used. They gave me a tutorial on how to recognize the correct schrader valve no matter what color the cap. The high pressure one is shorter and fatter than the low pressure (the one I wanted) which is taller and skinnier. Also, the fill nozzle will not fit on the wrong valve. Turns out my high pressure one had a red cap, and was pretty visible on the top of the engine just above the compressor clutch/pulley assembly. There are a plethora of hoses and lines going across that area, so I finally got a little step stool and stood on it while I searched among them for a second cap which everyone said had to be close to the red one. After forcing some lines out of the way (careful not to break or disconnect anything) I finally felt another cap like the red one. I unscrewed it and it was black. However, it WAS from the low pressure port. The guy at O'Reilley's said it likely had been replaced at some point.
Even with the long hose on the fill nozzle of the refrigerant can, it took me a long time to connect it to the schrader valve. There were just so many things in the way, and at no time could I actually see it. It was all by feel. So, I followed the instructions, turning the air on the dash to full blast. I dialed in the ambient temperature as instructed.
Not good after that point.
The clutch on the a/c never engaged. Could it be because the ambient temperature was only 54 degrees? The lowest temperature to dial on the gauge was 75. I squeezed the trigger once to see what happened, and the gauge immediately went into the red. I unplugged everything, and am back to square one. Could there be a problem with the a/c clutch? I don't recall it not coming on before. Is there a chance it will work better if the temperature is above 75?
It appears that my serpentine belt is okay. No cracks that I could see.
Any ideas would be appreciated.
Stan
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Stan,
Usually when the clutch won't come on it is because the pressure is below where the pressure sensor allows the compressor to run due to low refrigerant. As long as the pressure started out below the recommended level you should be fine. You need to get a temp for charging that is on the scale so that you have a calibrated charge. If it is 54 degrees and you use 74 degrees on the scale you will have over charged.
It is normal for the gauge to go high as you add some charge given the compressor is not pulling in the R134a and is stopped. It is a slow process but you can hit the trigger intermittently and then let the pressure decrease a bit and then hit it again and the compressor should eventually come on once enough pressure is in the system. The low side pressure will equalize with the high side pressure with the compressor off but it is a slow process due to a small orifice in the path. Once the compressor comes on you will still see increases on the gauge as you add but the reading will settle to the true system operating value in a few seconds with the trigger released.
With the compressor off you are basically trying to fill the system through a very small hole until the compressor engages.
Later Ed
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Thank you so much, Ed. I'm doggedly determined to learn these things, but I will never, at my age - 66, learn what you and others on this forum seemingly have at your fingertips. I salute all of you. I spent my entire working career as a pencil pusher, and although when I was younger I changed my own oil and filters, that is the extent of my knowledge over the years. I do understand the principal of an internal combustion engine but have little practical hands on experience.
I will be back at it as soon as it gets warmer! We're leaving Thursday for a leisurely trip to Gillette by the 14th.
Thanks again!
Stan
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Stan,
From the existing gauge calibration you should be able to rough estimate where 55-60 degree needle location would be and that would be close enough if you wanted to give it another try before Gillette. At Gillette you could probably get a hand from someone if you do not get to it before then...we only learn by doing and I was a pencil pusher also but I always liked working with my hands. I'm 64 and things do not stay with me like they used to...
Determination is a good thing, just be careful and you should be fine.
Later Ed
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Good info, Ed. Thanks.
I'm having a problem with my dash air also: I have a set of dual gauges and know where to connect them. The low side port at the compressor has a defective Schrader valve so that I cannot fill there. AHA!!, but Beaver added another low side port at the evaporator housing behind the removable panel in the nose of the coach, so I fill from there.
However, here's the issue: the low pressure switch will not let the compressor start. With the compressor jumped straight to the batt and running I cannot get the high-side pressure anywhere near the 220psi (or so) level, and the low side pressure goes up a bit then settles back down to around 15-20psi no matter how much R134 I add. Then when I shut the system down, the low and high sides take about 3hours to equalize. I've been told this is not normal and both symptoms could be caused by a partially plugged orifice (the small one you metioned).
What say you?
Andy
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Andy,
There is usually a screen leading to the expansion valve that may be plugged. Most likely source is a bag of desiccant in the receiver dryer might have broke. This is really a guess. The expansion valve may also be a culprit here. The fact that you cannot get the pressure up indicates that the compressor may be bad or a blockage keeps it from having available R134A at the suction side. You could talk to a local air shop and see what they would do if you brought it in. If you have to break into the system you would need some new Orings, a vacuum pump to evacuate the system, an new receiver drier, replace the Schrader valve, probably a new expansion valve and flush and clean the screen and piping from the drier if you have desiccant in the screen. This is deeper than I have had to go in repairs so I am offering a semi educated guess. As with all these things you have to decide where your skills end and a good shop's skills is required.
Later Ed
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Thanks, Ed. I have the equipment to pump down and fully charge the A/C system, but not what's required to pump out and collect the R-134 that's in there. I cannot, in good conscience, vent it to the air, even tho' it's less damaging to the environment than the old R-12, so, it looks like A/C shop time is in order.
Thanks again.
Andy
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Andy,
Good luck with it. You should be able to find a reputable shop near home. I like having things like this done near home in case the repair does not hold up. If you have collected that equipment then you are in good shape to provide the right info to the repair shop. Enjoy your summer and travels.
Later Ed