Charging Air Conditioning System

Hey BB!
Ok, I finally was able to replace the evaporator and refilled (for the 7th time) with 134a. Compressor came up and cold air was flowing again. Not the greatest but at least when it down into the 80's down here is works pretty good.
It has now been almost a month since the change and it is still holding. I think I am going to buy a set of Red Tek and wait till spring to install. If the system holds the 134 through the winter I will be more comfortable it will hold the Red Tek for some time.

Keep you updated but even a little cool is good:lol:
MT

Well my brand new, OEM, Denso compressor failed on me after only 4 months of use. Yes I was using R134a, and I guess it's my own fault. They have a 1 year warranty but you have to have proof a shop installed it. This was an expensive mistake:wall:

That sucks. Do you think the system could have been overcharged? FWIW, overcharging is hard on compressors and is a leading cause of failure. Tim

I will admit I have made "shop" invoices for work I did myself to claim warranties. It has always worked, never once was I questioned. I would make a detailed invoice using a template I found online. To be clear, I never used actual shops information. I used all my own info, and made up shop name.

I figure I was a tech in a shop for several years, and ran my own auto repair business as a side job too. I feel I'm more than qualified to install parts. If they want to play games to save a buck, so can I.

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Originally Posted by timsrv

That sucks. Do you think the system could have been overcharged? FWIW, overcharging is hard on compressors and is a leading cause of failure. Tim

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I used about 80% of the factory requirement recommended for a dual climate/refrigerator system. I believe I did everything correctly, but I have been using the crap out of the AC (daily driven and AC always on) so I guess I got my money's worth, but disappointed it didn't last more than a few months.

Still working my AC issues. When the system is fully charged and working the cooling is horrible. Checked everything from 134 levels to air routing but no help.
I finally went to another shop and I was told something I literally did not believe.
So if any of you heard this one please chime in.
He told me that the reasons why the 134 was not as cold as R12 was due to the condenser fan. Yep, he claimed that the fan was not cooling the condenser enough to make the AC real cold. He said it was all that was needed for R12. He believes a bigger fan would improve this greatly. Is there any truth to this??
If it is true, has anyone tried doing this?
I am getting close to heat down here in Florida and would love not to roast this year.

MT

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Originally Posted by MyToy

Still working my AC issues. When the system is fully charged and working the cooling is horrible. Checked everything from 134 levels to air routing but no help.
I finally went to another shop and I was told something I literally did not believe.
So if any of you heard this one please chime in.
He told me that the reasons why the 134 was not as cold as R12 was due to the condenser fan. Yep, he claimed that the fan was not cooling the condenser enough to make the AC real cold. He said it was all that was needed for R12. He believes a bigger fan would improve this greatly. Is there any truth to this??
If it is true, has anyone tried doing this?
I am getting close to heat down here in Florida and would love not to roast this year.

MT

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He might be right to an extent, but R134 systems use a parallel flow condenser compared to an older serpentine style condenser like what is in the vans. The parallel flow condensers are a lot more efficient. I guess because the R134a isnt as efficient as the R12, it needs more cooling, but I'm not entirely sure a larger/better cfm fan would solve that issue.

I'm working on cooling/ drying my compressed air with an automotive AC condenser right now, and from all I've been reading, it is the condenser itself that is the biggest culprit. The 134 is not nearly as efficient as the R12 was, so when the switch was made, the manufacturers went to stacked plates condensers instead of serpentine tubing condensers (lots more area). I do not know which kind we have on the van but it might be worth investigating. Then again, it doesn't matter how big is the cooling area is if you can't bring cool air to it so a good sized fan might be all that's needed!

OOOPS ncbrock beats me to it :)

I agree with the above responses. The van's AC system was designed for R-12, so anything else you use will likely give you less than desired results. I'm still running R-12 and don't plan on ever changing over to anything else. That being said, even with R-12 the AC on these vans isn't the greatest. It's adequate for long drives, but not so great bringing a hot van down to a comfortable temp on the shorter drives. I would think anything less efficient than R-12 would make the system inadequate. Tim

Wow!!! You mean this guy could be right????

OMG, I thought total BS.

OK, so if that is the case what would happen if RedTech was used instead of 134?

Would both that and a bigger fan maybe get it cold?

Sorry guys, I am still nodding my head in disbelief.:no: Thank you so much!
I will start researching fans.

You say you are experimenting with an automatic condenser, what is that about. Is this something I can also capitalize on ?

MT

I'm far from an expert here because changing Freon types brings us back to the original engineering specifications (so it's an engineering question). The type of Freon used in a system is at the foundation of design and changing that creates huge variables. I personally don't think a bigger fan will completely solve the issue, but it would likely have a positive effect. Of course running a bigger fan would require more power and that could have other negative effects on the already weak charging system. To a small degree, this would also result in more heat generated in the engine compartment, and getting rid of engine heat is already an issue with these vans. Changing the condenser to something designed for 134A would likely have a bigger effect, but if you solve that problem, who's to say the evaporator(s) and/or the compressor wouldn't now become limiting factors. If going back to R-12 isn't an option then perhaps heat exchangers designed for 134A could be a solution. Unfortunately, unless you have the time, ability, tools, and materials to do this yourself I don't see it being a cost effective solution.

i can't find the link right now but if you get really desperate for cold AC i've seen a VW van with no working AC rigged up with an inverter generator on a rear rack powering a small regular portable AC inside the van that vents the hot air out a side window. the van's owners lived in the SW desert and needed AC big time in the summer and said it cooled off the van interior really well. AC ran off a remote control. obviously this is not optimal an optimal setup

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Originally Posted by MyToy

Wow!!! You mean this guy could be right????

OMG, I thought total BS.

OK, so if that is the case what would happen if RedTech was used instead of 134?

Would both that and a bigger fan maybe get it cold?

Sorry guys, I am still nodding my head in disbelief.:no: Thank you so much!
I will start researching fans.

You say you are experimenting with an automatic condenser, what is that about. Is this something I can also capitalize on ?

MT

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I've heard amazing things about the red tek refrigerant. I believe it runs super efficiently and if I remember correctly you only charge it about 30% of the r12 value. I have cans of this ready to be swapped in in place of the r134, but the r134 worked well enough for me so I never swapped it out.

Tim is right, the AC system already isn't the best with R12, and with r134a it really isn't optimal. I'm not sure about my vent temps, but on a 90+ degree sunny day, the system can barely keep up, it's going to be a little uncomfortable (although still better than windows down). On an 85 degree cloudy day, it works decently enough to be comfortable. The sun is a killer.

Speaking of add-ons, Thermo King, Carrier, and possibly other manufacturers make add-on AC systems for vans and refrigeration purposes (catering and food transport vehicles). I was considering such a system for my van but these are commercial systems that come at commercial prices ($3,000 + for just the parts). The only one I'd seriously consider would be direct drive, meaning an engine mounted compressor with pipes carrying the Freon to and from the rooftop unit. If you could not do it yourself it would be a very expensive installation.

There are also RV type electric rooftop units, but these would only work when parked and plugged into power. A generator could be used to run during driving, but mounting, venting, rigging, sound proofing, etc would expensive and problematic (not to mention the space issue). There's also the possibility of powering off a large alternator with an inverter, but that's not without a large price tag and it's own set of problems.

Considering what a PITA add on vehicle AC systems can be, the type of system shown below starts looking much more appealing. Tim

http://i8.photobucket.com/albums/a23...pscyaprlbl.jpg

I'm not an expert and definitely do not have Tim experience with this, but it seem to me we are not trying to push more gas through the system, just to cool that same amount of gas better, so the compressor and evap. should be fine. No?

MyToy, Your Van is a 2wd therefore the ac condenser is cooled by the mechanical engine fan pulling air through it. How does your guy propose to make the fan bigger?

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Originally Posted by Carbonized

I'm not an expert and definitely do not have Tim experience with this, but it seem to me we are not trying to push more gas through the system, just to cool that same amount of gas better, so the compressor and evap. should be fine. No?

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Yes, I agree that a good efficient condenser with cool air moving past it is definitely the most important issue here. However, a properly engineered system is usually preferred over one that's been hacked and modified. Once you start making changes other unexpected things can happen (that was the point I was trying to make). If you find a way to retrofit a modern condenser/fan unit here (designed for R134A) I think you will see a marked improvement. Tim

MT - I would have called BS on that explanation too, glad to know there are far more intelligent peeps around.

If the system's bits are now functioning as designed and there are no further leaks and you aren't bothered about warranties, then I would probably give the Redtek a chance.

Its easy and cheap and if it doesn't work, you can still re-engineer the system :)

I totally get your point, but the hacking started with the switching gas and we are eternally going to be chasing the next weakest link :LOL2: