I needed to replace my low pressure switch on my dryer (again) and I was a little low so I decided after resisting it for 8 years, to convert from R12 to R134a. I bought the kit with the high and low valve adapters and the gauge with the hose for filling. The kit also came with cans of the R134a for high mileage cars so it had the sealant. I also got a can of R134a with the dye along with the light and glasses. My conversion went like this... I originally thought I was just low so after venting the remaining R12, I used the kit to fill it up. Then I discovered my pressure switch was bad because my compressor wasn't kicking on except when I would wiggle the pigtail plugged into the switch. I bought a new switch and bought 3 more cans of R134a but this time I got the cans that said "synthetic" and "18% Colder". I replaced the switch and after bleeding out all the prior R134a I put in there, I then used the 3 cans of this synthetic colder stuff. It actually took about 3 1/2 13once cans to get my system pressure to a consistant 56/57psi. 3 cans would have been the exact 2 1/4lbs the system called for but that only left it at around 50psi. The instructions said 55psi for 110degrees outside temp and it was like 112 that day so I said **** it and went a couple psi over for piece of mind. Anyway, it's just not nearly as cold as I remember it being with the R12. I knew it was going to be a little warmer but damn, it seems allot warmer. I mean don't get me wrong, it comes out the vents cool, but not ice cold like the R12. Do I need to do a complete 100% flush and clean of the system and re-fill again? I'm thinking all the oil and crap left from the R12 and now the 2 recent fillings with the R134a left just too much crap in there and so it doesn't have as much of the actual gas to compress so it's not getting as cold as it should. Does that even make sense? Is that possible? I can either have an A/C shop do a complete flush and clean for me, then I'll fill it again with R134a to save $$$, or I can also have them fill it back up with the old R12 stuff. Which do you think I should do? Money is an issue but if I should go back to the R12, I'll run with the R134a I have for a bit until I save up for the R12. If I can just stick with the R134a, is there even better stuff I can buy that will be colder than the synthetic 18% cooler stuff I already tried? Any ideas?????? Thanks!!!! Oh and sorry, I don't have a thermometer to measure the temp at the vents right now. Alex

Wow, I started reading after posting and this thread really opened my eyes:

http://www.thirdgen.org/techboard/co...st-review.html (R406a "Autofrost" review)

please stop venting refrigerant into the atmosphere. you are killing the planet. AC shops can evacuate the system for you properly.

Also you cannot mix r12 & r134. It is a little more involved than just switching refirigeant. Not a DIY job.

I feel really stupid now, sorry guys! I'll never just bleed it off again, I'll be using an A/C shop for sure from now on. Plus I'll be having an A/C shop next week flush and clean my system before adding some R414a that I just bought a few cans of on eBay. That way there will be no chance of mixing and I will have the peace of mind knowing I did it right. I'm glad I only have 1hr or less run time on my A/C since doing the switch and the R134a.

Thanks!

your welcome, and thank you for doing what you can not to kill the planet. is r414a the "autofrost" stuff?

R414a was similar to R406a (Autofrost).

R414a had R124b in it. Cooled almost as well, cost a bit more to make. Some worry about liver damage from leaked R124b. No R124b in R406a.

R414a was only briefly made during the 1990's. It also used the nickname GHG-X4.

R406a used to go by the name GHG-X3.

It's a bit complicated, but basically when you hear Autofrost, it's referring to R406a.

R414b is HOT SHOT. Another brand of R12 substitute.

well, some of the certified "AC shops" are competent enough to evacuate the system properly.

man did i cringe when i watched the kid at the shop i took my car to vent a bunch of my R-12 straight to atmosphere. this was after he screwed around with the wrong conversion kit for what seemed like an hour. so much for doing the right thing.

i recommend the op get a good thermometer to measure the cooled air at the vent so he knows how it compares to others. mine measured a frosty 35.6 F and is holding up nicely after more than a year. i figure if a problem develops in the near future i will go back and tell them i would hate to report them to the EPA.

DJ, before you get all full of cat hair by rolling on the floor laughing, re-read the part where he says he "vented off the remaining R12"

you dont know what your talking about.. R12 could put a hole in the ozone but too bad it cant get more than 20 feet off the ground! the only reason they made it illegal was the company got bullshit research cos they lost the patent for r12 and made r13