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Topping up R134a AC system

20K views 13 replies 7 participants last post by  marshall 
#1 ·
New to working on AC systems and ran into my first snag with what to do buy for refrigerant in Canada as R134a is only available in 30 lb cyclinders.

My compressor is cycling on/off every 10 seconds with low side from 10 lbs up to 35 lbs as compressor cycles and high side around 100. Seems to me i just need a little refrigerant.

All i can find in small cans is Red Tek and Duracool that are R12a and "compatible". The recommendations on label are to drain R134a and replace with these new refrigerants. Many comments on websites are no issues experienced with mixing so i think i will give this a try. Anyone have good or bad experiences with topping up R134a system with these new refrigerants?

My compressor is oily around the front so a seal is probably leaking. Some day it will need a complete repair with new compressor, remove refrigerant, vacuum, etc and at that time the refrigerant change over can be done. For now i was thinking a top up charge and see how long it holds. May last months or years, would like to find out before doing the full meal deal.
 
#5 ·
I have thought about these options. The US is about 2.5 hours away so i should probably just suck it up and buy 30lbs now. Thing is i have not had to mess with AC systems much, seems every five or so years there is a significant issue to fix and so hire it out. So i could buy 30lbs to have to fix this tractor properly and then wait for the next problem, by then there will be another refrigerant on the market to retrofill a r134a system and then i should look at buying that.

I would like to learn more on AC systems and would not mind taking on replacing the compressor some time. What do guys do for vacuum pump and reclaiming refrigerant ? Can this be rented or do you buy the equipment? 30 lbs of R134a is around $220 ($140 plus $80 cylinder deposit). If i take on doing the compressor job myself and can line up the equipment to do it then buying 30lbs now becomes a better idea as i may do more of my own work as needed.
 
#6 ·
There is a new refrigerant in cars already 1234yf and its only 10 times more $ than 134a and about 10% less efficient. I hope the ag sector doesn't get it for awhile. A long while. You can get a vacuum pump and reclaiming unit for less then 1000 bucks while a complete charge station runs $3000. Seems like a lot but it sometimes takes days to get someone to come fix a ac in the heat of harvest.
 
#7 ·
This refrigerant issue is just another government racket to drive up gdp by forcing people to change because government says so. R134a was the answer, now it isnt. I heard about the new refrigerant in cars and i bet it lasts 10 - 15 years then a new regulation will come out.

Leaning towards buying 30lbs of R134 while i can still buy it without a license. I see vacuum pumps are a few hundred $$$ and since new farm equipment still uses R134 i will have equipment on the farm for a few more decades to use it on.
 
#8 ·
Replace the pump if the seal is leaking or it will just cost you a fortune in the long run because it's about to lock up

Buy the 134a 30LB cag, or a couple, it's not like they are expensive. if you are not well experienced find someone that knows what they are doing to top them off


Don't mess with unfamiliar refrigerant because some contain butane and that might sound fine until your equipment starts on fire some day
 
#9 ·
Alright, think i will buy the keg while i still can. Just got the tractor in spring and noticed oily by the AC compressor. Assuming the short cycling and oil is related but want to top up system first and run it to be sure. I have the clutch unhooked ever since i noticed the short cycling. I cleaned up the oil so if i get the system topped up and run it and notice oil again around the compressor and pressures drop then i know for sure what needs to be done. At this moment i am making assumptions with no validation so not keen on yarding off compressor just yet.
 
#10 ·
The short cycling is because the low pressure side is getting too low, and compressor generally only leaks when the front bearing is going out.

There is oil in the system and it leaks out with the refrigerant, if you change the pump now it will be a pretty seamless job, if you wait to see if it blows up when it does it will contaminate the system and if a good job isn't done you will get to do it all over again. A fourth the downtime and less than half the cost to do it now
 
#12 ·
I expect that is what i will be doing SWF, will get myself setup with a vacuum pump and read more about what i need to do. Will probably start a new thread since adding the correct amount of oil to an empty system is a mystery to me right now.

As for the scale, that is another issue i have with only buying large containers, seems like an unnecessary PITA to try and meter out 3 lbs to fill a system from a +30lb unit. A digital 50lb fish scale is probably the way i can get best resolution as a bathroom scale may not give as good resolution.
 
#14 ·
In Manitoba can't buy anything for a refrigerated system without a ozone protection number -- not even the valve cap . So buying a canister is probably a good idea but knowing what and how to repair the A/C system will save you a lot of problems down the road . I have my tag but still use a lot of redteck on the older equipment as it is cheaper and cools better than Freon . I would look at getting a front shaft seal as that is what is leaking . They aren't that expensive but you need some tools to be able to replace it . If you could get someone to vacuum out the 134a then just putting red teck in would probably work until the seal really leaks . They sell seal swell red teck but I don't have any faith in that .
 
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