Date: Sat, 10 Aug 2019 18:20:17 +0000
Reply-To: Richard Koerner <rjkinpb@SBCGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Richard Koerner <rjkinpb@SBCGLOBAL.NET>
Subject: Re: Fixing Vanagon Air Conditioning....trying at least
In-Reply-To: <BL0PR20MB2098689753923671DC73571DA0D10@BL0PR20MB2098.namprd20.prod.outlook.com>
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Thanks so much for this insight and wisdom, Dennis; I will take my Vanagon to professionals next week for refrigerant recovery and recharge; there is a A/C shop nearby that is Vanagon savvy. Better to be safe than sorry. And there is still a lot of summer and heat left, so it will be nice to be cool.
Rich
San Diego
On Friday, August 9, 2019, 7:46:13 PM PDT, Dennis Haynes <d23haynes57@hotmail.com> wrote:
Things can get a bit more complicated but basically the trying to do everything yourself becomes false economy. For a basically sound system having a shop do a recovery and recharge should only be about an hour’s labor plus the cost of refrigerant. Your approach can wipe out the system very fast. Once a compressor breaks up and fills the system with metal debris you have a real mess.
In addition as you are in California the cans in the auto parts store are only available due to loop holes in the laws, one of the reasons they are less than a pound. While not ozone depleting R-134a is a greenhouse gas and is regulated as a refrigerant. Getting caught intentionally filling leaking systems or worse intentionally venting a system can have some hefty consequences. Shops have to have the techs certified and the equipment they use is also regulated. There is an investment there.
Another problem with R-134a is that when it does leak out, not all the elements leak out at the same rate. What remains is not the same as what went in. Just topping a system off gives you something that just doesn’t perform as it should. Recover and refill gives me consistent results. Sucks to add a pound or two and end up with weird pressures and having to do a full recovery and recharge to get it right.
As for the AC system sealers, like too much oil they are also a contaminant that reduces performance. Also they can coat the insides of the coils making for an insulating layer further reducing performance.
Also for using gauges the pressure-temperature chart on the gauge is referring the coil-refrigerant temperature. Not necessarily the air around it. Ideally what you really want is to use a gauge set with thermo probes and charge to get the ideal superheat.
Dennis
From: Richard Koerner [mailto:rjkinpb@sbcglobal.net]
Sent: Friday, August 9, 2019 9:11 PM
To: vanagon@GERRY.VANAGON.COM; Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Fixing Vanagon Air Conditioning....trying at least
Hi Dennis and thanks for some specifics regarding optimal fill using R-134A, A typical (Walmart 12 ounce can) is 340 grams. Simple math says 1300 grams is 3.82 cans; 1400 grams is 4.12 cans; 1500 grams is 4.41 cans. When I chose to "refresh" my A/C with new freon to make up for lost freon, I really had NO idea of how much freon I still had in my system. Using the "gauge" method, and based on my ambient temperature of 75F, I kept shooting for that ideal low side pressure of 35 PSI. I ended up filling with 4 full cans! Thus, since I probably had at least "1 or 2 cans" left in my system since it was working and blowing cool but not cold, I really think I have overcharged my system.
Yes...ideal method would be to take it to a shop, have them evacuate to get rid of water but also to get to a Zero start point, To do this though, gets expensive, as well as a hassle taking to shop. I'm trying to think of a way to estimate Freon loss; and then recharge on, say, a quarterly basis; year round, even in winter when thoughts change to things like Mr Buddy heaters and Chinese diesel heaters for nighttime camping comfort. Buying a vacuum pump and fittings to do the evacuation is really not a viable option for me; nor is investing any more money into the Vanagon/Subaru A/C system. Heck...I had gone for 30 years or so in my Vanagon without A/C and it was fun to get it working again; it's super duper when it works....but not the end of the world to not have it work like a modern car.
Also, another can of R-134A Stop Leak next spring before system recharge is another option for me; keep the leaks at bay.
GoWesty had it right when they said that Air Conditioning in a Vanagon is a tough challenge. I think they used stronger words.
Rich
San Diego
On Friday, August 9, 2019, 2:47:14 PM PDT, Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:
An important part of repairing any AC system is to do the repairs timely and stop trying to use if it is obvious something is wrong. It may appear the system is under pressure so nothing should enter it but if refrigerant is leaking out them most likely moisture laden air is entering. This is especially true of any leaks on the low pressure part of the system which includes the compressor shaft seal. Even when properly charged there are conditions where the low pressure side can go into suction.
Moisture is bad for number of reasons. In addition to the corrosion of coils, compressor parts, expansion valves, etc. if enough water droplets make it to the expansion valve it can get clogged instantly and with being no internal pressure relief damage to components happens fast. Broke valve plates, bent crankshaft, destroyed clutch, blown condensers, hoses, receiver, etc. happen very fast. Systems that failed for some time should always have the receiver/dryer replaced and the evacuation should be an extended time pull down with a "micron' gauge used to let you know everything that does not belong has boiled out. Before this it is best to test the system using nitrogen. Charge to 250 psi and see if it holds at least overnight. Then evacuate and charge.
Oil level is also important and so is the type? Ester oil is often used for conversions since it will help keep the R12 mineral oil in suspension. If doing a really good conversion with new compressor consider the PAG oil. Use a multi or get the correct viscosity for the compressor being installed. Quantity is critical. Too much since the oil is a non-condensable it becomes a contaminant and reduces system performance.
R-134A has to be charged by volume. There are to many variable to just use pressure gauges. It is always best to fully recover what is left and then fill by volume preferably with new. I don’t know why but it seems that the stuff in cans does not work as well as bulk from the 30Lb bottles. The late vanagon systems seem to work well at 1,300 to 1,400 grams. At 1,500 the radiator fan spends a lot of time at higher speeds due to excessive pressure.
As for the old hoses, expect for hoses or fittings I have not had much luck fixing leaking systems by replacing them. With regular use and adequate oil in the system the oil will help keep the stuff inside. Small leaks in the condenser, compressor seal and expansion valve are common. If you have black gook or coating near the compressor clutch that is a sign of a leak there.
Dennis
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