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Old 07-06-2020, 03:36 PM   #1
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Some Questions Regar ding disconnecting AC Refrigerant Lines

I am getting ready to take down the big air conditioner evaporator unit at the back of my bus. I am concerned about disconnecting the refrigerant lines. It appears that the refrigerant lines are hoses that have crimped-on band clamps holding them on to some barbed nipples. I don’t see any way to disconnect the lines without either cutting the hoses or undoing the crimped bands

I am pretty sure that the refrigerant is R-134. Can I just open the lines and let the refrigerant escape into the atmosphere? Once the evaporator is disconnected from the lines is it enough just to cap off the lines and the fittings with some plastic or rubber caps.

Also, I am willing to invest in a vacuum pump and a charging manifold and even a scale to weigh my refrigerant. Should I expect that I can vacuum out and recharge this A/C myself?

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Old 07-06-2020, 04:03 PM   #2
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Most of what you propose doing is actually against the law for very good environmental reasons.
(yes it IS a federal crime to knowingly vent refrigerant to atmosphere)

There are safety reasons as well...

Ideally, if you're sure you need to remove the system at all, take the bus to an automotive hvac place where they can safely, legally, responsibly remove the R134a for you.

That said: the lines are disconnected at the fittings shown in your pic.
After opening the lines its best practice to cap the lines to keep dirt & excess moisture out of them.

In the future you can (with deposit) borrow a vacuum pump and gauges from most of the auto parts chain stores if you wish to evacuate/recharge the system.

Please read up on a/c systems before you do any damage to you, your bus, or the environment.
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Old 07-06-2020, 04:11 PM   #3
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Maybe I could use a kit like this to re-clamp those A/C refrigerant hoses?

https://www.amazon.com/Proster-Singl.../dp/B07KPGW9X8
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Old 07-06-2020, 04:15 PM   #4
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Originally Posted by wrenchtech View Post
Maybe I could use a kit like this to re-clamp those A/C refrigerant hoses?

https://www.amazon.com/Proster-Singl.../dp/B07KPGW9X8
If refrigerant gets in your eyes you will be blind -- you're welcome!
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Old 07-06-2020, 04:16 PM   #5
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Most of what you propose doing is actually against the law for very good environmental reasons.
(yes it IS a federal crime to knowingly vent refrigerant to atmosphere)

There are safety reasons as well...

Ideally, if you're sure you need to remove the system at all, take the bus to an automotive hvac place where they can safely, legally, responsibly remove the R134a for you.

That said: the lines are disconnected at the fittings shown in your pic.
After opening the lines its best practice to cap the lines to keep dirt & excess moisture out of them.

In the future you can (with deposit) borrow a vacuum pump and gauges from most of the auto parts chain stores if you wish to evacuate/recharge the system.

Please read up on a/c systems before you do any damage to you, your bus, or the environment.

"Most" of what I'm proposing to do is illegal?

I know that venting R-12 is illegal. For the sake of this discussion let's assume that venting 134A is it illegal, what else is it that I'm proposing that you think is illegal?
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Old 07-06-2020, 04:45 PM   #6
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The air-conditioning unit that I am proposing to open is not running at the present time due to low refrigerant. If I can rent a vacuum pump at the auto parts store and buy the refrigerant from any number of suppliers, I find it pretty hard to believe that what I propose to do will be breaking the law.

Additionally, rules that the EPA put in place extending the regulation of ozone depleting refrigerants to substitute refrigerants, like R-134a, was deemed to be an overreach and has been repealed effective March 2020.

https://www.govinfo.gov/content/pkg/...2020-04773.pdf
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Old 07-06-2020, 04:53 PM   #7
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If refrigerant gets in your eyes you will be blind -- you're welcome!
Thanks for the warning. I will be sure to wear personal protective gear.

Are you also opposed to amateur builders doing their own propane piping? I'm fixin' to do that as well.
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Old 07-06-2020, 05:02 PM   #8
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Knowingly venting ANY refrigerant is illegal, regardless of which one. There's is a license issued by the EPA to allow someone to work on AC systems and recover them correctly.

It's not hard to get, but the equipment is costly. Will you get caught? Well... unlikely, but you did post on the internet your intentions. lol j/k

It's basically the same as DEF deletes.... they tend to go for the big fish. Am I not condoning venting it though, that's just bad practice.
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Old 07-06-2020, 08:32 PM   #9
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Knowingly venting ANY refrigerant is illegal, regardless of which one. There's is a license issued by the EPA to allow someone to work on AC systems and recover them correctly.

It's not hard to get, but the equipment is costly. Will you get caught? Well... unlikely, but you did post on the internet your intentions. lol j/k

It's basically the same as DEF deletes.... they tend to go for the big fish. Am I not condoning venting it though, that's just bad practice.
It seems like you didnít read the linformation at the link that I posted two messages before yours. It is from the federal register. What you say about the laws was true up until March of this year,. Now, apparently, it is OK for a non-commercial entity to vent refrigerant into the atmosphere. And why not, the refrigerants in used for the last 30 years are no more harmful for the environment than cow flatulence.
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Old 07-06-2020, 09:00 PM   #10
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My initial statement may have been somewhat unclear. I talked about detaching some refrigerant lines from my evaporator coil assembly. And I talked about what to do with the refrigerant that remains in the system. I was not talking about detaching the lines while they are under pressure.Of course I would first attach a gauge and manifold set up to the system ports to find out what the status of the refrigerant is in terms of pressure. If there is pressure in the system, it can be safely vented with that device. Once the system is depressurized It would be as safe to work on anything else.

What I am looking for advice on, is how to deal with refrigerant hose connections made with barbed fitting’s and crimped band clamps. The existing hoses are at least 12 years old and the system is low on refrigerant, which indicates that there may be some minor leaks. Perhaps new hoses are in order, but I shudder to think of the cost as it is about 30 feet from the condenser to the evaporator. Although the high pressure Hose is probably much shorter.
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Old 07-06-2020, 09:26 PM   #11
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I just found out that it is possible to buy a good refrigerant leak detector for as little as $25!!
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Old 07-06-2020, 09:33 PM   #12
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I took my bus to a local mechanic shop, they charged me $100 for a "disposal" fee knowing full well they just get to keep it in their machine and resell it to the next customer that needs refrigerant


but yeah, don't let that stuff into the atmosphere, illegal or not.



also make sure you safely disconnect the electrical supply going to the AC system. The Transair system on my Bluebird had a dedicated breaker panel that got power from the batteries even with the ignition off. I almost got shocked when I was taking down the AC evaporators inside.
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Old 07-06-2020, 11:00 PM   #13
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It would be best to find a manual for your AC system. There may be isolation valves that will allow you service sections of your system without removing refrigerant from the entire system. You will also want to get a manifold gauge set to see how much refrigerant is in the system. If the system has no pressure you likely have a leak which should be repaired prior to recharging the refrigerant. It will often be oily where there is a leak. You can also get dye that can be injected into the system that will glow under UV light. Another common practice is to recover the refrigerant and then pressurize the system with nitrogen to find larger leaks. The manual should have all the test procedures for your system.

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Old 07-07-2020, 12:14 AM   #14
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It would be best to find a manual for your AC system. There may be isolation valves that will allow you service sections of your system without removing refrigerant from the entire system. You will also want to get a manifold gauge set to see how much refrigerant is in the system. If the system has no pressure you likely have a leak which should be repaired prior to recharging the refrigerant. It will often be oily where there is a leak. You can also get dye that can be injected into the system that will glow under UV light. Another common practice is to recover the refrigerant and then pressurize the system with nitrogen to find larger leaks. The manual should have all the test procedures for your system.

Ted
Thank you! Finally, some useful information for me to act on. The refrigerant hoses connect to some barbed fittings which screw into a block at the back of the evaporator unit. The copper lines from the evaporator coil enter the block from the other side. There are some hexagonal fittings on the block, not all of which are fasteners, I think. Perhaps one of these actuates a valve to close off the evaporator unit. The units are made by Carrier. If I can get a manual for this equipment I will be as happy as a pig in you-know-what.
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Old 07-07-2020, 07:38 AM   #15
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you can unscrew the fittings from the Block expansion valve, you dont need to cut or disconnect the bands on the lines. . those are male fittings so put a wrench on and take it off the nut should rotate without turning the line too once you get it loose it should swivel.. that way tyou dont destroy the hose or the fitting. . those are burgaclip or EZ-clip style fittings and are easy to re-crimp if you do happen to damage one by accident.



I dont know of any law that allows refrigerant to be vented, there should be a label someplace on the bus by the manufacturer of the A/C system that tells you how much refrigerant it holds.. i find thyem sometimes on thye battery box doors, the electrical panel door or sometimes affixed to each compressor.. that will tell you how much to charge back in when you go to bring the system back online..



sometimes I have to take an adjustable wrench opened wide on that block if its not secured well.. yours looks to be bolted to the evaporator frame so you should be fine.



if the system is a TransAir or ThermoKing the VIN number of the bus can be called into their customer service and they can tell you all about it as they are still in business..



Ive never seen isolation (king) valves on a school bus A/C uness it uses the 6 cylinder coach compressor vs the dual sanden compressors.. I have seen them on Coach A/C systems and they are common on commercial / residential systems.



you can have a shop recover the refrigerant out and tell you how much they pull out.. they can weigh it out.. then you can safely take it apart and yes tape or cap the lines and the ports on the evaporator.. you dont want dirt to get into that Block.. if your system has a receiver / dryer (blue or black small canister in line with the small pipe near the condensor) you will want to replace that when you get ready to put the ysstem back in service.. this helps to get rid of excess moisture from the system being un-sealed while you do your conversion.



here are some examples of what a reciver / dryer might look like



https://www.transairmfg.com/bus-air-...pe=pcs&id=1012


recharging it isnt too bad to do.. the best way is to weigh in the charge if you have the full charge info on how much to put in.. its tricky to weigh it in using the little cans you buy at auto-zone as you never can get all of it out of the can while charging.. most bus A/C systems hold 5-8 pounds of refrigerant unless its a large single-compressor coach-style system they can hold uo to 20.. I dont know your particular installation but im guessing you have 2 separate systems..



like banman said you'll want a vacuum pump, set of gauges and of course R-134a..



if you lived closer id help you take it apart and put it back together..



-Christopher
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Old 07-07-2020, 09:25 AM   #16
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Thanks for the warning. I will be sure to wear personal protective gear.

Are you also opposed to amateur builders doing their own propane piping? I'm fixin' to do that as well.
Not at all opposed to any DIY done right...

Since you mis-identified the fittings you were looking at and asked about cutting perfectly good lines that can be removed with a wrench I concluded that you don't know what you're doing... yet...

As to the EPA reg. I suspect that you've misinterpreted it. If you can pull out of the actual reference to venting to atmosphere I'd like to see it.
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Old 07-07-2020, 09:39 AM   #17
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Yep...What Christopher said....


That said, if you want to replace the rubber hoses, I just did mine - I was also low on refrigerant and I didn't want to play whack-a-mole, especially with 2 hoses running next to the exhaust pipe, touching the exhaust bracket; I found Summit Racing to have the cheapest AC barrier hose I could find. They didn't have one of the sizes needed, and I got a Goodyear hose elsewhere (eBay). Both say "Galaxy" on them - like the "generic" one from Summit was actually made by Goodyear? They seem to be the same quality of rubber (neoprene I think). It is all new to me..... I know that I will never buy Gates automotive hoses again, even though the parts people tell me "They are premium, and the biggest hose manufacturer"; My low-pressure carburator fuel line lasted less than 2 years before it cracked and leaked gas. My radiator hoses were crunchy within a couple years, also. Goodyear! Good hoses (but lousy tires compared to BF Goodrich)



I didn't have the barbed fittings, I had crimp-on "bead-lock". I had to order all new ones from these guys (they take PayPal, but you won't see that option until you check out; I don't like to give just any website my card info...):


https://coldhose.com/



They had all but one of the fittings I needed. I got that one from a hydraulic hose manufacturing company that wanted 2-3 times as much to make the hose than the cost of making them myself. Where coldhose wanted about $7 per fitting, they wanted $20. But gotta have it so...


The cold-hose website also says:

If you have the barb style fittings with hose clamps it is recommended they are replaced with beadlock fittings.


I ordered a crimper tool on eBay:
https://www.ebay.com/itm/Hydraulic-H...72.m2749.l2649


There are some crimpers on eBay that are a bit cheaper, also.


My system is made by Rifled Air. They never returned any inquiries I had.


Attached is a spreadsheet I put together for the parts I needed. It may be a bit confusing at first - it makes sense to me, though...... Ignore the parts that say "tip length" or "tip ID / OD". I don't mean to suggest that it shows what you need, only to give you an idea of what goes into doing this, and baseline pricing. It shows OReilly's prices, but I did not use them, since they had to order the hoses, and it would be a while. eBay came though fast....


I got my receiver/drier (filter) from NAPA:


https://www.napaonline.com/en/p/TEM2...put=tem+208122


I found it by putting in the part number on the drier (33241) and doing an "interchage search" on NAPA's website.



TJones said:
Another common practice is to recover the refrigerant and then pressurize the system with nitrogen to find larger leaks.


At the u-tube college of technical engineering and fine arts, I learned people who have a gross leak (and currently no pressure/refrigerant) in the system charge it with compressed shop air to about 150psi to find the leak. Then you MUST replace the drier. Chances are, if you currently have some pressure in the system, the leak is at an o-ring on the tip of one of the fittings or a slight hard-to-find crack in a hose, so shop air is not really needed. Only for gross leaks.



I had a shop evac my system, then had them recharge it. I installed the new driers in their lot just before they evaced it to recharge it; they don't like being exposed to the atmosphere for long. Nice cold air now! Except for the power distribution conundrum with the battery isolator I'm having that won't power the AC system with the isolator connected. But that's another problem altogether...


In the end, it was maybe about $1000ish altogether to replace the hoses myself. (Note I have 2 separate systems) With the labor involved, I could see a shop charging $2000-$3000 including new hoses. They would use Pirtek to make the hoses, which would have been $1200-$1500 alone. I don't recommend Pirtek, besides the exuberant prices. Already had probs with them making me a custom hydraulic tranny-fluid hose.
Attached Files
File Type: pdf AC fittings.pdf (17.1 KB, 2 views)
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Old 07-07-2020, 09:42 AM   #18
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My understanding of EPA regs, is that you must be certified to CHARGE someone else $$$ to work on their system. If you work on your own system (and do it for yourself for free), then you are OK; but you still SHOULDN'T vent the refrigerant to the atmosphere....
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Old 07-07-2020, 09:51 AM   #19
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My understanding of EPA regs, is that you must be certified to CHARGE someone else $$$ to work on their system. If you work on your own system (and do it for yourself for free), then you are OK; but you still SHOULDN'T vent the refrigerant to the atmosphere....
Knowingly venting to atmosphere is breaking the law for anybody -- not just "certified or licenced" professionals...

Will you get caught? No. Are you still breaking the law? Yes.

Are you a piece of sh!t for not caring about the environment -- I will of course say yes, but that's just my silly opinion about science, health and things of that nature...
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Old 07-07-2020, 09:55 AM   #20
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I took my bus to a local mechanic shop, they charged me $100 for a "disposal" fee knowing full well they just get to keep it in their machine and resell it to the next customer that needs refrigerant

SNIP....
The problem is that unless the shop has a way to filter the gas they removed from your system they can't reuse/resell it w/out risk of damage to someone else's system.

Some DIY folks put low quality stop-leak-products and even propane in their R134a systems for example -- crap you don't want in your properly repaired hvac...
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