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Re: C2 A/C Freon hose/clamps
Tim
The high side pressure on an automotive R -12 system should be 170 to 210 PSI the low side should be 30 to 40 PSI. I dont know how they could have gotten the pressure that high. This will sound stupid but maybe they have the properties of R - 12 confused with another refrigerant? -
Re: C2 A/C Freon hose/clamps
Thanks Bill. I thought the pressure in system was way too high. I know Dom Tallarita tested compressor to about 340 psi when he rebuilt it. Found a different a/c shop from talking ParagonComment
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Re: C2 A/C Freon hose/clamps
Tim some shops are not equipped for us old time refrigerant guys. I hate to admit but my 67 was converted to R - 134 A with an after market compressor.Comment
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Re: C2 A/C Freon hose/clamps
I searched HIGH/LOW(no pun intended)for a shop that still had a R-12 machine/gauges and experience .They assured me they had it all under control. Well maybe NOT!! Unsure where they got their info. Their paperwork(receipt)says (system was filled w 2 lbs 12oz of Freon and prior to hose separating a/c was operating with high side higher than normal near 380 psi STILL in normal range for limited air flow across the condenser) Hoping Larry Mulder will see this and offer his opinion thanksComment
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Re: C2 A/C Freon hose/clamps
Tim:
I tell folks to STOP if pressure exceeds 250 psig with R12. Anything above this...... except for Arizonia in the summer....... is too high.
The nitrogen check was good. Perhaps they did not get all the air or moisture out of the system (by vacuum pump) before charging with R12. That.........or getting engine bay really really (really) hot...........likely caused the excessively high pressure that blew apart the hose at the fitting.
An experienced R12 shop guy would never run system pressure above 250psig without knowing what he was doing and what could happen.
Many folks have used the LICS hoses with no issues. But special AC hoses clamps with a locator arm are used to secure the hose to the fitting. I believe the LICS hoses are a "barrier hose" for R134a..........and as such may have a tendency to slip at fitting under very high pressure unless the end fittings are (double) crimped for true R134a service.
Engine bay must have been an oily mess as well. Hopefully they (or you) added the proper amount of R12 oil into the system (12-13 oz) before attempting a recharge. If they did not, that is incompetence. Empty A6 compressor takes about 6-7 oz oil and rest of system takes about 6 oz of oil.
Fix what broke and double (or triple) check hose end fitting clamps for proper design as well as for tightness. You almost cannot tighten "too tight" on the hose clamp screws with screwdriver or 1/4 ratchet............the hose wall thickness is quite thick and the clamp is not that robust.
LarryComment
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Re: C2 A/C Freon hose/clamps
Tim:
Dom uses a type of ESTER oil now in his rebuilds. Not certain when your A6 was rebuilt by him........but if in the last few years, it likely contained the ESTER oil. R12 specifies mineral oil, but proper viscosity ester oil is also fine. Ester oil can also be used for R134a. That is why Dom puts it in his rebuilt compressors.........the car owner can use his oil for both refrigerants.
R12 system capacity is 3 lbs and 4 ounces.......or 52 ounces R12 refrigerant for a full system, starting from empty. R134a only requires about 80% of that number, or 42 ounces. This is due to a number of differences in the two refrigerants.
I wonder if your AC techs added the additional oil before charging (?), due to no oil spray in engine compartment. Try not to mix oils, so all oil should be per Dom's recommendation, if he rebuilt your compressor. MOST AC shops likely don't use ESTER oil very much.........they use PAG oil for R134a and MAYBE (maybe) remember to use 525 viscosity mineral oil for R12. But R12 stopped being used by car manufacturers back around 1990, or 30+ years ago........so many younger techs don't know.
If you want to discuss more, then call me. Just let me know if you want/need to do this.
Larry
EDIT: Tim, the 250 psig upper pressure limit is MY recommendation for most folks. System may be able to go higher in extreme conditions or SW USA summer conditions, but you need to know what you are doing when you push your old system above the 250 psig mark.
EDIT(2): For the majority of cars running R12, the typical discharge pressure of the compressor is around 180-230 psig.Comment
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Re: C2 A/C Freon hose/clamps
Larry,
I have a question for you also. Would you be okay with me calling?
Sorry Tim for intruding.
ThanksComment
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Re: C2 A/C Freon hose/clamps
Larry could you give me your phone number and time zone?
ThanksComment
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