Current Cost of Freon

[Joe Camper]

Great discussion we have going thanks for all the input.

I reckon no one has ever heard of the freon loss at the compressor shaft seal during periods of cold weather and nonuse or closing off the valves on the compressor to eliminate it. As explained to me yesterday this  is common in these compressors not too old. Had no replys here one way or the other???

I was told a compressor with a seal that holds fine in summer can leak as much as 75% of the freon out the shaft seal left to sit over the winter. He sucked out what I had so he could then put in exactly 24lb and when he only got 6 lb out of it I thought for sure I had some work to do but he told me no.........the shaft seal.  This compressor was rebuilt with new seals on both ends 3 yrs ago too.

He runs the shop at Central States Charter they are a prevo authorized shop here in Chicago and they still run H-3s with r-12 in them and this is how he services them too.

He also noticed the high side needle bouncing slightly, it shouldn't, and it looks like I'm gonna pull the heads and check the valves  again all this stuff is 3 yr old. Defiantly gonna take some photos along the way. He thinks I have a cracked reed or a plugged orifice or a bad unloader.

What kind of compressor oil does propane require

[luvrbus]

I see where that might would work sitting for long periods for a rv but a charter bus I have my doubts the AC is part of the dehumidifier function on a H series I don't have any ideas about your system.
On a H series if the system is not in good shape that function does not work but no problems here we use the AC about every day year round lol 


good luck

[Joe Camper]

Your right.

On ours in the winter when heat is needed the defrost works way way better if we continue to select a/c over heat, and then turn more heat in with the thermostat to get the desired temp. If you try to defrost in heat mode it totally sucks.


Good trick for prevo with OTR A/C

How in the heck do folks without otr a/c deal with this. Or buses with the dash air not functioning?

Lots of towels up at the dash LOL

I do believe he practices what he told me thou dumb drivers probably dont know any different.

[belfert]

Dina never had any way to get air conditioned air to the defroster.  To date, just heated air has worked out okay.  The one time in winter weather we really needed the defrost it wouldn't work at all.  It turned out that a wire had come loose from the switch.

[norules]

sorry - my mistake

here's the data on Freeze 12 - (non propane)

http://reviews.ebay.com/Freeze-12-Refrigerant-R134a_W0QQugidZ10000000005615895

[Flatspot]

It is a good idea to 'valve off' the compressor for extended times of non-use, isolating the compressor from the rest of the system. That said if you are sure that the rest of the system is leak free. The shaft seal is partially made with the refrigerant oil in the seal. If it sits gravity takes over with the oil and the refrigerant can leak past the seal. You need to make sure that the compressor isn't operated with the service valves closed (front seated). I'd disconnect the clutch to make sure that the compressor doesn't operate. Another approach would be to pump the refrigerant into a receiver. I don't know if your bus is equipped with one. If it is, there is a procedure to do that.
I am an opponent of propane in a mobile application. That said I have over 200# R-12 but I am an EPA certified tech as well for mobile A/C. I will sell you R-12 installed in your rig, after is is deemed leak free, for $19/lb. Industry list is quite a bit more than that.
R-409 is a drop in refrigerant for R-12 and I've used it successfully adding it to the existing R-12 in a system. Not much loss of efficiency.
As far as the needle bounce, discharge pulsation is normal. Are you having performance problems?

[luvrbus]

Jones I am sure glad you are my personal AC guy now I know were to get R-12 lol


good luck

[Joe Camper]

Yes, seems like last time we got recharged it was blowing colder and the ambient temps were higher too.

Another month and some warmer temps and I will know for sure.

I very much like my OTR A/C but I need to pick up as much as I can if I had to pay every time I needed repairs I could not afford it.

Pulling the heads seemed like something I could do, and wanted to, even if they check out O/K I will have learned more in the process.


Picked up a r-12 recovery recycling machine and a digital scale off of Craigs list for 200 bucks last year already had a vac pump and guages.

Learned a bunch already reading and listening and watching and experimenting.

How long is the class to certify and can it be done over the computer at home?

[Busted Knuckle]

Dina never had any way to get air conditioned air to the defroster.  To date, just heated air has worked out okay.  The one time in winter weather we really needed the defrost it wouldn't work at all.  It turned out that a wire had come loose from the switch.

Brian first off the defrost system on a DINA SUCKS on a charter bus loaded with passengers! I've been the driver of more than one that had problems clearing the windshield. Also it's not the air conditioned air on the windshield that clears it. The A/C sucks the moisture out of the air and helps the defroster do it's job.
 BK  

[Lin]

Can propane mix with R134 or would the system need to be purged first?

[Nick Badame Refrig/ACC]

Hi Joe,

Flatspot is correct that discharge pulsation is normal in a vehicle. You have alot of variables in idol speed that can contribute to this.

We also use 409-A as a direct replacement for R-12 and have since the early 90's with no issues at all. Yes, compressor seals do dry

out but, remember that there are usually 10 to 18 other seals in the system too.. Not as large as the compressor seal but just as

capable of leaking refrigerant. Don't forget all the rubber hoses too..

As far as LP in the system, I wouldn't trust it with discharge presures upwards of 400psi in certain conditions.

Good Luck
Nick-

[buswarrior]

Yes, there are lots of northern fleets that used to isolate the compressor or pump it into the receiver for the winter.

But, the defroster needs outside air in order to keep the windows from fogging up.

Works just fine on an old coach, but the newer coaches have issues.

We haven't been able to get R-12 in Canada for many years? What happened to the phase out?

happy coaching!
buswarrior

[artvonne]

We haven't been able to get R-12 in Canada for many years? What happened to the phase out?

buswarrior

  My understanding is its being smuggled in and the EPA is looking the other way. It is not manufactured here anymore and likely China are the only ones left making it.

  As far as LP/Propane/R290 in an AC system, 134a uses a different oil than R-12/R-22. Propane is compatible with R-12/R-22 oil and o-rings, 134a is not.

  While I understand the initial fears of Propane in an AC system, if you research the net and honestly read about it, you quickly learn 134a is just as explosive, in fact more explosive as its been known to autodetonate within the system, and form deadly toxic gases when burned. Propane will not autodetonate unless there is considerable air in the system (oxygen), and propane does not form toxic deadly gases when it burns.

  IOW, once you are forced to move away from R-12/R-22, if you can accept 134a, you shouldnt be any more fearful of Propane. The reality is that it is very rare to see an escape of refrigerant into the cabin of any motor vehicle, rare that it would find an ignition source, and rare that it would reach the correct mixing ratio of gas to oxygen to support ignition. Propane is one of those gases that has a very narrow range of ignitability, too much or too little Oxy and it wont ignite.

  And even if it did, if the worst happened, say your sleeping, the Bus fills with gas from an evaporator leak, it somehow reaches the proper mixing ratio, and miraculously something sets it off. KaBoom. It would likely blow all the windows and drapes out. It might cause some minor flash burns to any exposed skin. Its unlikely any further fire or damage would occur. Personally I am more afraid of the junky cheapo RV propane appliances like Suburban LP furnaces, LP water heaters, LP refrigerators and LP stoves. Of those, I probably have more confidence in the stove.

[luvrbus]

R-12 is still made they make it in India and export still available in Mexico I paid 25 bucks for a can last year.
I never could get my arms around the EPA deal and freon the stuff leaks out or there would not be replacement how do capture something leaking at 70 mph or on a home AC when it gets low where does that go in the air is all I can figure lol
I have a 90 model Jeep that uses R-12 and I don't plan on changing to 134 leaks out about pound every 2 or 3 years

[artvonne]

  No one ever knew the ozone hole even existed until 1979, but of course once found, it HAD to be man doing it, so companies like DuPont, who now had 134a they wanted to manufacture and sell patent rights of, funneled money under the table to PACS and funded University projects to find a way to prove it and ban R-12. Now a report from NASA says the hole may have more to do with solar wind, that at higher solar energies which cause faster solar wind, it strips away ozone in the upper atmoshere over the poles, and at low speed periods, like we are seeing with the Sun today, the hole is virtually closed up. In fact now they are saying our efforts to reduce GW may actually be making the effects worse and may lead to GC. We'll never win, lol, just shoot us.