Before I Hurt Myself... - PeachParts Mercedes-Benz Forum

Adriel · #1 08-31-2014, 11:56 PM

Went to change the Schrader valve on the low side, started removing, and got hissing. Gauge shows 0 and the A/C compressor isn't coming on. Figure I better check so I don't hurt myself.

Is it alright to just slowly vent the remaining pressure?

How much of an environmental impact is there releasing a small amount like this into atmosphere?

Thank y'all in advance!

vstech · #2 09-01-2014, 12:02 AM

if gauges are at 0, and you are hearing a hissing, the gauges are bad...

legally, I'M NOT ALLOWED TO VENT REFRIGERANT. my reclaimer pulls a system down to 10" of vacuum.
if you have R12 in it, an easy tool for removal under pressure is available online. 134 tools are also available, but not as easy to get... amazon has them. search for pressurized schrader valve tool... you'll find it.

mannys9130 · #3 09-01-2014, 12:06 AM

Depends on how much is actually in the system. If you think it's all out you're fine. If not, liquid refrigerant will freeze your fingers and hurt you.

If we're talking Federal law, you should have an EPA 609 certification like me to work on mobile A/C units. Law requires recovery of both 134 and 12. If it's R12, the damage to the Ozone layer is really high. If it's 134 the damage is low but it's still a greenhouse gas. I'd condone venting an ounce or so of 134 but not 12.

If you replace the valve core, you will need a deep vacuum to remove moisture. Why not just have the car evacuated at a shop, change the core in the parking lot, and have it vacuumed for 30-45 minutes before you leave?

cooljjay · #4 09-01-2014, 12:43 AM

Ah don't worry about it.....there is sooooo much more bad stuff going into the ozone every day....your little r12 won't do anything....sheesh was watching a thrift dump gas/oil out of old lawn mowers into the gutter....Then I seen a old 1930's fridge in the truck....yeh they will forsure vacuum that out...

Adriel · #5 09-01-2014, 12:46 AM

Quote:

Originally Posted by vstech

if gauges are at 0, and you are hearing a hissing, the gauges are bad...

legally, I'M NOT ALLOWED TO VENT REFRIGERANT. my reclaimer pulls a system down to 10" of vacuum.
if you have R12 in it, an easy tool for removal under pressure is available online. 134 tools are also available, but not as easy to get... amazon has them. search for pressurized schrader valve tool... you'll find it.

Quote:

Originally Posted by mannys9130

Depends on how much is actually in the system. If you think it's all out you're fine. If not, liquid refrigerant will freeze your fingers and hurt you.

If we're talking Federal law, you should have an EPA 609 certification like me to work on mobile A/C units. Law requires recovery of both 134 and 12. If it's R12, the damage to the Ozone layer is really high. If it's 134 the damage is low but it's still a greenhouse gas. I'd condone venting an ounce or so of 134 but not 12.

If you replace the valve core, you will need a deep vacuum to remove moisture. Why not just have the car evacuated at a shop, change the core in the parking lot, and have it vacuumed for 30-45 minutes before you leave?

Thank y'all for the help!

Not sure why I didn't get notified...

My friend who was an A/C technician is the one who loaned me the tool and I am almost certain he has a recovery tank. I will just call him in the morning and see if/when I can have the system vacuumed. I rather be safe!

Why do I have to have a license when it is my own vehicle? They sell refrigerant even in the stores.

I have only had one issue and that was when a fitting didn't work and ended up inhaling R134a; it didn't feel good...

Oh and the system is R134a, but still has R12 fittings. We just use R12 gauges and get it close.

Adriel · #6 09-01-2014, 12:51 AM

Quote:

Originally Posted by cooljjay

Ah don't worry about it.....there is sooooo much more bad stuff going into the ozone every day....your little r12 won't do anything....sheesh was watching a thrift dump gas/oil out of old lawn mowers into the gutter....Then I seen a old 1930's fridge in the truck....yeh they will forsure vacuum that out...

If I had seen that, I would have contacted someone about it. Old gasoline is nasty stuff!

It is R134a, which is ozone depleting, but you are right, others are dumping it whilly nilly, so I need to be more responsible.

What concerned me more is my safety concern. I had forgot about the freeze risk, but it was in my subconscious apparently.

cooljjay · #7 09-01-2014, 12:56 AM

Oh yeh, the freeze risk is the worst part...

Oh you wouldn't believe the stuff I find around here in the dumpster and getting dumped....I thought California was bad..

I have to take pics of the washes out here, they are nasty, stained permanently black from the crap that runs down them...its amazing....and I like in a place full of native americans....long long gone are the days of them caring for the land...

Adriel · #8 09-01-2014, 01:17 AM

Quote:

Originally Posted by cooljjay

Oh yeh, the freeze risk is the worst part...

Oh you wouldn't believe the stuff I find around here in the dumpster and getting dumped....I thought California was bad..

I have to take pics of the washes out here, they are nasty, stained permanently black from the crap that runs down them...its amazing....and I like in a place full of native americans....long long gone are the days of them caring for the land...

What kind of stuff? I believe you!

I guess when I get up there I can see myself, though can you show me pictures?

Yes, I know what you mean. I can tell when I am on the res: time has slowed so projects are half done and trash about. I wonder if it is because of the mindset created by the welfare state/casenios? When I was in the four corners area seemed every Native male was drunk or trying to get drunk. Seems there are still a few that do care about their land.

pgringo · #9 09-01-2014, 01:19 AM

"If it's R12, the damage to the Ozone layer is really high." or at least that's what federal regulators tell us. whenever anyone tries to tell me about how something causes the big holes in the ozone layer at the poles which lets in more UV from the sun, i have to refer to science...UV creates ozone. where do the sun's rays bombard the least? why, the poles of course.

cooljjay · #10 09-01-2014, 02:38 AM

Quote:

Originally Posted by Adriel

What kind of stuff? I believe you!

I guess when I get up there I can see myself, though can you show me pictures?

Yes, I know what you mean. I can tell when I am on the res: time has slowed so projects are half done and trash about. I wonder if it is because of the mindset created by the welfare state/casenios? When I was in the four corners area seemed every Native male was drunk or trying to get drunk. Seems there are still a few that do care about their land.

Oh man, TV's by the boat load....electronics of every kind and cans of who know what...there is even recyclables like aluminum and cardboard....It saddens me alot!

I don't know what it is, only thing I can think of is that since they live on the res, get monthly checks, free medical....they just don't care...and here....its like everyone owes them, we are their slaves they can do anything they want...really horrible....oh man, yeh they are total drunks...they pass out all over the place here, behind dumpsters, lawns, ditches, stores....its crazy...

Oh and don't leave your car unlocked....when you wake up...you will find one sleeping it in, we got a couch on the front porch...keep waiting to find one sleeping on it...already found them sitting on our back porch drinking....shesh even the one behind me, poisoned one of our trees...

leathermang · #11 09-01-2014, 06:53 AM

Quote:

Originally Posted by Adriel

.......Oh and the system is R134a, but still has R12 fittings. We just use R12 gauges and get it close.

THAT is Illegal..
and just wrong on many levels....
Shops pay a lot of money to have proper working recovery units....
and you can cost them a lot of money not having the proper valves on there... so they know what is in there....

leathermang · #12 09-01-2014, 07:09 AM

Quote:

Originally Posted by vstech

.........legally, I'M NOT ALLOWED TO VENT REFRIGERANT. ......

Adriel,
Lets clarify this a little....
VsTech is in a different classification than you and I are... he is an AC Professional.... with the correct tools and thus different responsibilities than the EPA holds YOU to.

For instance.... it IS LEGAL for you ... in your process of checking your system for leaks when putting it back together...

to VENT 4 ounces of R22

mixed with ( a dry inert gas like Nitrogen, Argon) which hopefully you used to check your AC system UNDER Pressure...so your fittings and seals are being checked IN THE WORKING situation...not under vacuum .....

Vacuum is needed as the first step in getting moisture out... but it is advised by many to use the same procedure that AC professionals use on HOUSE systems... triple evacuation ..... putting dry nitrogen into the system... then pulling it out three times.....

And for the record... from a LOT of reading on AC stuff... you need several hours at least for the vacuum phase to do a reasonable job on getting the moisture out...it has to SIT at the most vacuum you can pull to ' boil ' the moisture out of pools of AC oil left in low spots.... and never gets all of it out... thus the recommendation to flush and refill the system with newly opened can of the correct matching AC oil...

mannys9130 · #13 09-01-2014, 08:34 AM

I was told that for non-hermetic A/C systems a 45 minute vacuum cycle was ideal. If you draw a vacuum for too long, atmosphere and more water can be drawn in through small leaks or by pores in the hoses. Hours is too long for a car A/C system.

Also, if you are to go through all the proper triple evac and N2 pressure leak test, you'd at least replace the drier as well. There has been no mention of replacing the drier. Why go to such trouble when the service will be fundamentally flawed in the very first stages?

leathermang · #14 09-01-2014, 09:12 AM

Manny,
Your join date is a year ago... you have 65 posts..... you have not been through the ' AC WARS '...
It is standard operating procedure that ANYtime a system is opened up the receiver dryer it to be replaced....and not just replaced.... but only opened up immediately before installation..
Try reading on ACKits dot com..aircondition dot com or that kind of specialty ac site... and get lots of opinions before deciding on which people are using facts and physics to make judgements ....
You were probably told that by a garage that did not want to take any more time than the minimum to get your car out of there to work on someone else's car...
If your hoses can leak from vacuuming then they need to be replaced... many these days are made with a lining different from the old days... due to the size of the molecules we now deal with.....
If your fittings leak... then you did not assemble them properly... meaning two wrenches to the proper torque...and you DID NOT use the concentrated oil of the proper color when assembling them.... can't think of the name of the stuff... but it is in the AC threads over the years...
As to not mentioning the dryer in this thread.... we can not put EVERYTHING into each thread...but we try to raise red flags where some concept looks like it may be missing..... some responsibility for general research falls on the individual... although if you read many threads you will get a good idea of things one needs to check out...

mannys9130 · #15 09-01-2014, 09:51 AM

I'm sorry I didn't realize that everyone had to be baptized by "the" A/C thread in order to contribute to A/C threads...

I may be wrong about the water being drawn into the pores of the hose. My reasoning is, R12 is a big molecule. R134a is smaller and will pass through an old r12 hose. H2O is even smaller than R134a. So why is it unthinkable that drawing a deep vacuum for several hours will pull in atmosphere from outside? It'll be a slow process for sure, but at which point do you reach the point of diminishing returns?

All I'm saying about the drier is, it's useless to explain a triple evac process, R22 leak check, and dry N2 leak check to someone that probably won't even replace the drier after the system is opened to replace a valve core. It overwhelms DIYers. He's running R134 with R12 fittings for Pete's sake! Do you really think he's concerned about all the other stuff?

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