AC Recharge FAIL

[LucaScali]

So I tried to recharge my late 80s AC system with this Envirosafe Industrial stuff. I know it isn't ideal using flammable hydrocarbons, but others have run it with success. It's supposed to cool well, it's cheap, doesn't require a vac, and the risk is probably manageable.

The system takes about 48oz or R12, which is equivalent to about two 8oz cans of the Industrial product. Since my system hadn't been recharged in at least 15 years, it was presumably empty or close to it.

Started off well, but before the first can had been fully emptied, there was a loud pop and a huge cloud of gas erupted. Luckily I wasn't near it. I suppose this was some kind of relief valve? I checked to see if any hoses had exploded and everything looked ok.

Later ran the AC and didn't look or sound like there was any kind of major leak. So what might of happened here? Why would the pressure have built up to such an extent before the first can was even empty? Pressure on the lowside was only around 30 when it happened, but it's some dinky hose that came with the refrigerant, not a professional set. Should i continue trying to charge it or would that be stupid? This is obviously my first attempt working with the AC.

Thanks very much

[porschyard]

When you say it does not require a “vac” are you saying that you did not pull a vacuum on the system before trying to charge it. I take it you are not monitoring the high side press and wonder if you are running a fan on the rear condenser and have checked to see if the frt fan condenser is working. Did the “cloud” come from the left front fender well, there is a high pressure relief valve in the receiver drier.

[LucaScali]

yes, that is correct. the instructions actually say not to pull a vacuum on the system and I confirmed this with the seller before attempting the recharge. You're also correct that I wasn't monitoring the high side; I didn't think it would be necessary in this case.

I wasn't running any kind of fans. I'm assuming the front fan condenser is working, but to be honest I didn't verify. the cloud came from the engine bay. I have no idea where the gas escaped from, and after it had stopped/dissipated (which was only a few seconds after the loud pop), everything looked fine. I thought it might have been the charging hose, but that looked ok too.

[LucaScali]

Upon closer inspection, the underside of one of the AC hoses is covered in some kind of oil, so that might be the one that ruptured, though it felt ok. I can't find anything else that would suggest something went wrong. Time to invest in some pressure gauges and possibly a new hose. Hopefully round two will go better.

[porschyard]

My advice would be to acquire a training manual for automotive A/C systems and try and educate yourself on at least the basics.
The info that you received about not evacuating the system (especially after sitting for 15 years) is baffling to say the least.

If the system has not been operating for 15 years I doubt that the frt condenser fan is working (which BTW is useless even when correctly functioning) and with no air flow across the rear condenser high side pressures can skyrocket pretty quickly. I don’t mean to come off as a negative Nelly and I wish I could give you some hope that you are heading in the right direction but it’s obvious you are not. Thank god that flammable Freon did not encounter a spark when the hose blew.

You are taking a 30 plus year old A/C system that really did not work that well when they where new that has been sitting dormant for 15 years and trying to just shoot some alternative Freon in W/O pulling a vacuum on the system or providing air flow across the condenser nor monitoring both high and low side pressures and expecting positive results is IMO wishful thinking.
I wish you luck in getting cold air from your vents especially in todays climate and as I said the best advice I can give is to educate yourself about the system before proceeding any further.

Richard

[911obgyn]

I am not an expert on AC but have done some in the past, the purpose of pulling a vacuum on the system is to remove moisture, by turning it into vapor under vacuum. My hoses on an 85 are so brittle and aged i would never attempt to even try to pressurise the system.

[EC900]

I used a DYI kit, AC Pro on a 20 yr old BMW and had good and quick success, even fixing an internal seal leak that contributed to the 134 loss after sitting for 2 years. I applaud your tenacity and willingness to get the tools to fix the system. But I think you answered your own concern - DYI didn’t yield a satisfactory result.

However easy these DYI ac recharge kits are, there are other things to consider like the pressures High and Low balance. The AC Pro and maybe the others only add to the Low side, even their connector is foolproof but it doesn’t account for or measure the pressure on the High side, which might be the reason your popped the relief valve. Too much on either side (H/L) will affect any ac system even on an otherwise working system, I don’t think or know if the DYI kits are intended for Full charge, but only to ”top-off” existing refrigerants, then and especially on an old unused system that likely has deteriorated seals and perhaps corroded aluminum lines or fittings could be a waste. An ac shop can pressurize the system and indicate maybe even locate leaks w/o using refrigerants and that would be the route I’d take but really, but anything over 40 yrs old is destined to have costly items to replace piece by piece going forward and that’s where I would draw the line and surrender to fix an oem ac system.

[GH85Carrera]

I can't imagine how a system sitting for 15 years is not just soaked in moisture. The "standard" rule of thumb for all ac systems starting over is to first replace the receiver dryer as a default.

With hoses that are that old, yea, good luck ever getting them to not leak like crazy.

Personally I would never use a propane or other flammable hydrocarbon based product, but that is me, and it is your car, do what you want to it.

It must be some magic stuff to not need a vacuum and clean system to work at all.

Good luck.

[LucaScali]

Like gasoline, Glen? There's obviously some added risk to a couple oz of flammable refrigerant, but all things considered, it seems minor.

Envirosafe argues that since hydrocarbons do not react to air, there's no need to pull a vacuum. It's a controversial claim for sure. I plan to pull a vacuum in round 2 anyway and maybe just find some r12.

Hopefully I've found the house that ruptured. The hoses actually look brand new. Not sure there was an unusual leak prior to this episode.

[Mixed76]

Originally Posted by LucaScali

Like gasoline, Glen? There's obviously some added risk to a couple oz of flammable refrigerant, but all things considered, it seems minor.

Envirosafe argues that since hydrocarbons do not react to air, there's no need to pull a vacuum. It's a controversial claim for sure. I plan to pull a vacuum in round 2 anyway and maybe just find some r12.

Hopefully I've found the house that ruptured. The hoses actually look brand new. Not sure there was an unusual leak prior to this episode.

You still don't want air in the system, it will reduce condenser capacity, evaporator capacity, and mess with your operating pressures. Doesn't have to be as good as water removal in a freon system.

Sent from my Pixel 7 using Tapatalk

[PeteKz]

Originally Posted by LucaScali

Like gasoline, Glen? There's obviously some added risk to a couple oz of flammable refrigerant, but all things considered, it seems minor.

Envirosafe argues that since hydrocarbons do not react to air, there's no need to pull a vacuum. It's a controversial claim for sure. I plan to pull a vacuum in round 2 anyway and maybe just find some r12.

Hopefully I've found the house that ruptured. The hoses actually look brand new. Not sure there was an unusual leak prior to this episode.

Agree on the relative risk. Gallons of gasoline is potentially a LOT more dangerous that ounces of propane/butane.

20 years ago I tried the hydrocarbon mixtures (usually propane and butane) in an old van of mine. It worked, buy not as well as R12 or even 134. Forget about the risk, I changed to 134 because it wasn't worth the hassle to use non-standard refrigerants.

[GH85Carrera]

Originally Posted by LucaScali

Like gasoline, Glen? There's obviously some added risk to a couple oz of flammable refrigerant, but all things considered, it seems minor.

Envirosafe argues that since hydrocarbons do not react to air, there's no need to pull a vacuum. It's a controversial claim for sure. I plan to pull a vacuum in round 2 anyway and maybe just find some r12.

Hopefully I've found the house that ruptured. The hoses actually look brand new. Not sure there was an unusual leak prior to this episode.

In just a minor leak, you get a nice cloud of explosive and flamable gas. Gasoline does not do that.

It ain't my car, and it ain't my life to risk, go with it if you want.

[porschyard]

Originally Posted by LucaScali

Envirosafe argues that since hydrocarbons do not react to air, there's no need to pull a vacuum. It's a controversial claim for sure. I plan to pull a vacuum in round 2

While I am not a refrigeration engineer I have been working on strictly Porsche’s for 40 + years and mainly on G series cars. I have repaired/replaced 100’s of A/C systems and as I said earlier this statement is truly baffling. As was mentioned earlier the moisture that will be in the system after that period of time of dormancy would absolutely require a new drier and evacuation as the moisture will cause all kinds of nasty long term problems like acid formation and sludging of the oil and short term issues such as freeze up of the expansion valve.

But air is a non condensable and not removing it by a vacuum causes immediate problems one being very high head pressure which will be the highest at the discharge hose from the compressor to the rear condenser (coincidentally the hose that burst) and as you mentioned the hose failed after only a partial charge of the alternative Freon.

The manufacturers advice of not pulling a vacuum goes against not only everything I have learned about refrigerant systems but also 40+ plus years of experience.

I am glad to hear you are going to pull a vacuum on the next go round but I would highly recommend a drier also.

Richard

[LucaScali]

Thank you EC, Richard, Pete, and everyone for the honest advice. I appreciate it. I should have obtained the proper hoses and pulled a vacuum from the start, but I was lazy and tried to take a shortcut.

[GH85Carrera]

Originally Posted by porschyard

While I am not a refrigeration engineer I have been working on strictly Porsche’s for 40 + years and mainly on G series cars. I have repaired/replaced 100’s of A/C systems and as I said earlier this statement is truly baffling. As was mentioned earlier the moisture that will be in the system after that period of time of dormancy would absolutely require a new drier and evacuation as the moisture will cause all kinds of nasty long term problems like acid formation and sludging of the oil and short term issues such as freeze up of the expansion valve.

But air is a non condensable and not removing it by a vacuum causes immediate problems one being very high head pressure which will be the highest at the discharge hose from the compressor to the rear condenser (coincidentally the hose that burst) and as you mentioned the hose failed after only a partial charge of the alternative Freon.

The manufacturers advice of not pulling a vacuum goes against not only everything I have learned about refrigerant systems but also 40+ plus years of experience.

I am glad to hear you are going to pull a vacuum on the next go round but I would highly recommend a drier also.

Richard

I ONLY work on my cars. AC is important to me. I learned from my father in law. And a lot from Pelican and trial and lots of error. I have to agree 100% not pulling a vacuum, and leaving the old receiver-dryer in place is just asking for problems for the reasons you mentioned.

Any vendor that states no vacuum is needed, is selling snake oil in my opinion. Just my opinion, I have been wrong before. But my AC simply works in the hottest temps and after a full day of driving in triple digit temps.

[LucaScali]

https://youtu.be/5i5qdwD6Dqk

This guy agrees with you, Glen. Lot of discussion about this on various boards. The company has a mixed reputation.

[GH85Carrera]

I honestly believe the biggest "secret" in good AC performance is a dry system. It is truly impossible to get too good of a vacuum. The better the vacuum the better the AC will perform. Moisture is always bad in any AC system. Those are real absolutes.