I am working on a walk in cooler that calls for r12 can I use r134a for it. If so any suggestions on flushing system.
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I am working on a walk in cooler that calls for r12 can I use r134a for it. If so any suggestions on flushing system.
I can offer you this good information on R-12 to R134A. I work in industrial refrigeration now for 20 years. I have seen R134A used in HVAC screw chillers, but right from the factory. I have no seen any large machine conversions mainly because the POE synthetic oil is very expensive. I used to have an auto air business and I converted hundreds of systems and this is what I learned. 134A runs about 17 percent higher head pressure then 12. When you convert the rule of thumb is install 80 percent of factory charge by weight. In a hermetic system (ALL metal Piping) I would flush the whole system thoroughly. If you have a semi hermetic or open system with any hoses or neoprene seals I recomend to just drain the system, but leave some mineral oil residual in the system to mix with the POE (Ester) oil. This will bond (Esterize) the rubber parts in the system. The POE is "great" oil as a lubricant and detergent qualities are great. Change driers and labeling. If you have a large oil capacity the cost of the oil will scare you. It is near 100 dollars per gallon. 134A is still pretty cheap compared to blends. By the way 134A is pure. It will not seperate. It is very good stuff, and the pressure temp chart is nearly identical. Use all existing TXV devices and orfices. Watch the discharge pressure ! Good lu
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