R-12 to R-134a

[SPoe]

Hello all, I've just overhauled my a/c system and converted it to R-134a since it was blowing about 80* in the cab and now with the R-134 in it only gets down to 60*. Also, my low pressure side is reading around 50 PSI and the high side is reading around 425 PSI. I'm on the 4th can of refrigerant and I'm still seeing bubbles in the sight glass on the dryer. Can anyone help me before I break down and take it some where to get it worked on?

 

[AClayton]

Sounds overcharged to me!If you are still seeing bubbles,that doesn't necessarily mean you are undercharged. Confirm your Condensor is 100% clean before charging by site-glass. Did you also replace the metering device and clean out all the old oil and flush thoroughly?



Also,is that reading while idling and running max cool?Rev your diesel up to about 1500 and check pressures then... . could be your fan clutch is not engaging also. Bubbles in site glass is evidence of not condensing.



What micron level did you evacuate to..... or how long did you have the vacuum pump run before re-charging?May also have non-condensibles in ref. system... air or incapatable oil is very likely the cause. When i have done these before,I throw a charge of R-22 in 1st... . more hygroscopic and will aid in moisture removal upon final pumpdown.



Hope this helps!!



Alan

 

[PToombs]

Sounds way over charged to me too. Outside temp has to be factored in too. Should be around 25-30 and 225-250 or so at about 75-80 degrees. I don't have the chart right here, but that should be close.

 

[tempforce]

should of used one of these.

Enviro-Safe Refrigerants

Duracool®.com 2004 - Duracool® is The Recognized Leader In Hydrocarbon Refrigerant Technology

can be used in r-12/22 or r-134a systems

cc

 

[KOG]

I've been doing auto A/C for over 30 years and have current licenses for both auto and residential refrigeration. After using 12, 134, autofrost, and a couple of other 12 substitutes I've settled on HC-12. Duracool is one brand name for HC-12, there are others available at lower cost. Better cooling, higher efficiency, easier on the compressor, slower leak rate and no affinity for moisture at all.

 

[BDaugherty]

R134 is different. You cannont charge a system based on bubbles in the sight glass. The best way is to charge by weight. You may be able to find a weight converter on the internet somewhere. However, for the average do it yourselfer, R134 is best charged with a temp gauge in one of the vents. Start charging and once you get the compressor to stay engaged, charge slowly until you reach the coldest reading on the gauge. Then add another ounce or so and you should be pretty close. Your gauge readings are useful, but not absolute. I would expect to see 35-40 psi on the low side. A system originally built for 134 will run slightly higher pressures than one built for 12.

 

[AClayton]

R134 is different. You cannont charge a system based on bubbles in the sight glass. The best way is to charge by weight. You may be able to find a weight converter on the internet somewhere. However, for the average do it yourselfer, R134 is best charged with a temp gauge in one of the vents. Start charging and once you get the compressor to stay engaged, charge slowly until you reach the coldest reading on the gauge. Then add another ounce or so and you should be pretty close. Your gauge readings are useful, but not absolute. I would expect to see 35-40 psi on the low side. A system originally built for 134 will run slightly higher pressures than one built for 12.

X2



Alan

 

[Greenleaf]

I had a shop convert my 92 to 134 and it didn't work right. I dumped it and converted the system over to HC12 and it is really cold.



There is also an adjustment made with the temp probe. It can be moved in or out to adjust the evap operation,,,,,, to a point. I like to think it made a difference... ... ... ...

 

[SPoe]

Where would I be able to find HC12 cuz I havent found a website that sells it.

 

[Greenleaf]

hc12a.com



or



G. Starkey 502-549-3789



or



HC Refrigerant



or



Northcutt 316-838-1477 1-800-279-3540

 

[LRutigliano]

Hello all, I've just overhauled my a/c system and converted it to R-134a since it was blowing about 80* in the cab and now with the R-134 in it only gets down to 60*. Also, my low pressure side is reading around 50 PSI and the high side is reading around 425 PSI. I'm on the 4th can of refrigerant and I'm still seeing bubbles in the sight glass on the dryer. Can anyone help me before I break down and take it some where to get it worked on?

4 cans at 12oz each = 48 oz !!! Your original R-12 charge was probably around 24oz (there is a charge label near the radiator support x-member).



Additionally, when converting from R-12 to R-134a, you should use approx 80% of the original R-12 charge, so you are WAY over charged.



Sight glasses and bubbles are not used for R-134a.



Also, you need to ensure you have an adequate PAG oil supply to the compressor. Typical single evap systems require 150 to 200 ml of PAG oil.



Hope this helps,

Louis

 

[SPoe]

Thank you for all y'alls help and information. I'm going to try the Hc12a and see what happens. I'll report back once that is complete.

 

[tempforce]

when my mega needs a recharge it's getting the system mod'd, it needs more air at the outside vents and much more cooling. so hc12 is going in. i'll have someone draw the system down, then i'll re-charge it.

when the home ac needs serviced it's getting changed as well. maybe it'll save some on the electric bill and cool better.

 

[mysteryman]

the 134 will ruin your system over time. use r12 or HC12 only.



134 will trash your compressor first. the piston rings shrink and it loses it's ability to compress... . It was designed for r12 and mineral oil... put it back the way it was!!!!!!!!!!!!!!!!!!!!

Hello all, I've just overhauled my a/c system and converted it to R-134a since it was blowing about 80* in the cab and now with the R-134 in it only gets down to 60*. Also, my low pressure side is reading around 50 PSI and the high side is reading around 425 PSI. I'm on the 4th can of refrigerant and I'm still seeing bubbles in the sight glass on the dryer. Can anyone help me before I break down and take it some where to get it worked on?

 

[KOG]

Shrink the piston rings? That's not going to happen. Seal problems, yes.