I have an 89 f-150 I am retrofitting to 134a. Everything has been replaced and flushed and a vaccum applied.
What is the correct charging procedure. I have seen those temp/pressure charts but do not fully understand them. Example: 134-a at 75 degrees has a pressure of 78. Someone told me that this means an outside ambient of 75 degrees should produce a pressure on the low side of 78. This does not sound right to me. 78 seems awful high or am I missing something?
Missing the fact that :
1- This is not an MHVAC group. 2-Retrofits with 134a on 12 units sucks, and is really dumb. 3-There are cheaper methods 4-Without your MHVAC card, however, you cant buy the refrigerant to do it. 5-Neither R12, nor 134a is in my old R12 unit....and it cost all of $10 in refrigerant....:)134 you can. 12 or blends you can't
Do you have a 609 licensee? And are all the service fittings on your vehicle EPA kosher for your blend? ;) I'm sure i don't have to ask how well it works.....
Bob
>
Yes, Yes, and works like a charm. :-)
Puuulease......been MHVAC certified since the first year it was required.
of course..no leaks, no glide, no errors..LOL .
Nope..cause it works like a charm.
Yes, you are very clearly missing something. Whoever is giving you advice is not doing you any favors.
You'd be better off going to The Automotive Air Conditioning Information Server at:
What you say makes no sense.
When converting to R-134a (after flushing and component replacment, never with a "kit) the proper way to charge the systemm is by WEIGHT. Aircondition.com has the exact number, but IIRC you should charge the system with R-134a to about 75% BY WEIGHT of the recommended charge for R-12. Charging by pressure requires using thermocouples on the liquid line and looking up the correct pressure in a pressure-vs-temperature chart. Much less accurate than charging by weight.
Why? I'm not the one with the problem. :-)
Mine works fine.
I take it you are using propane?
Yup.... I took my '91 S-10 and had it retrofitted with a drop in replacement....they recovered the residual R-12, evacuated the system, replaced a bad seal, weighed in the correct charge of Freeze 12, tested it, and gave me a 1 year warrenty....for all this, the shop charged me less than $100. Been running it for 3 years with no problems....the air coming out of the vents runs 48 - 52 degrees consistantly. Even though I bought a 609 cert, and could have very easily done it myself, I don't work on my own vehicles...its not worth my time to mess with it.
Under Federal law, there is no such thing as a "drop-in replacement" for R12 in MVAC.
You left out the part where they installed non-removable service fittings unique to Freeze-12 and a permanent retrofit label installed prominently under the hood so that future service techs know to turn you away and say "Sorry, we do not work on systems that are not charged with R12 or R134a, because it contaminates our service equipment and the refrigerant supply".
...Or did they "forget" those legally-required parts of the job?
About 10 degrees warmer than it should be.
...so you know exactly why your system as described is illegal.
DS
didn't change the fittings, but the label was affixed.
nope
actually not.... with the addition of outside air that routinely runs 85 -
95 degrees with 90 - 95% RH, thats normal, and yes if I run "max A/C" with no outside air, the temp will drop.
Hmmm, with any luck, it will be their equipment and their refrigerant supply that gets contaminated, along with a lengthy supply of comeback vehicles that don't cool properly.
So their failure to comply was intentional?
Still nowhere near as good as both of my R-134a systems.
Actually, under federal law, there are several, however, the term, drop in, is not accepted, due to the fact that in most cases, while little may need to be done to the vehicle to make it work, the fittings alone need to be changed, thus, the removal of a direct drop in term.
you do know what the SNAP program is dont you?
Funny..Noon is a tech...so it matters little...
R134a retrofits plain ass suck in R12 apps. Various reasons why...therefore, a SNAP approved alternative works better than 134a will everytime..charged correctly.
I believed that line for YEARS. And I also believed that my old Chrysler systems with RV-2 compressors and EPR valves would be among the worst conversions imaginable.
But it turns out that if you do it right and remove the EPR valve (and install an evaporator temperature controlled clutch cycling switch instead) it works pretty well in those old systems. The main requirement is a large condensor area compared to the evaporator. Minivans and SUVs make terrible conversion cnadidates, most cars do OK if done correctly. My '69 Dodge, converted to R-134a, blows 38-degree air in 98 ambient with 50% humidity when cruising down the highway. All stock A/C components except seals and the refrigerant. Stop-and-go requires using MAX (recirculated air) to keep the temps down below 40, but they do stay below 40..
Same story with GM and other brands- doing it RIGHT involves more than just flushing and changing refrigerants and oils. With orifice tube systems, you need to switch to a Smart-VOV instead of a fixed orifice tube, just like you need to get rid of the EPR valve in EPR-valve systems.
why...therefore,
everytime..charged
silly question...........how do you keep the evap from freezing with sub 40 degree air coming out of the vents?? figuring a 10 to 15 degree air temp drop across the coil, that tells me the coil temp is below 32 degrees.
Think refrigeration...
Dumb F*ck Bill, Thanks for helping me prove my claim that you're just a stupid f*ck.
Jabs
No big feat. What's it do in 98 ambient with 50% humidity when *stuck in traffic*?
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