# Identifying an Unknown Refrigerant



## David40

Just wondering if any of you guys have any tips or tricks when it comes to identifying an unknown refrgerant, whether it be an unmarked tank or a hacked system where there are few clues as to what gas might have been used?


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## Saturatedpsi

You could narrow down the field using saturated pressure for a known saturated temperature...assuming it's in a saturated condition. :001_unsure:


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## JohnH1

In a tank measure the temp of the tank and then the pressure in the tank and use a PT chart to get you close.
In a condenser run just the fan for 15 or more min without the compressor and use outdoor ambient and system pressure to cross the PT chart.
This is assuming someone did not mix the Freon.


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## David40

Thanks, that's about all I could think of too.
Too bad nobody makes a leak detector that can also read out the refrigerant type. Ops, did I just give away a million dollar idea.


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## user2561

*Be careful!!*

While using the pressure temperature relationship to indentify refrigerants and possible mix ups is great for some situations, it can be risky in others. Some refrigerants, especially in refrigeration, have almost spot on pressure temperature relationships at certain temperatures. This can make for a huge mistake. For example, you run a call on a walk-in freezer that doesn't indentify refrigerant being used. Now you're faced with a Dilemma b/c you know it needs a charge but are unsure of what refrigerant was used. Going by pressure/temperature could get you in hot water b/c if the system was originally R12 some replacements have similiar characteristics when using the pressure/temperature technique. 

This is where it is better to remove the refrigerant remaining per EPA, fix the leak, and find a suitable replacement refrigerant for R12. Make sure to think about the oil as well. Some use POE, some use Mineral/akl. Some gaskets/seals do not play well with POE.

Another handy way to identify refrigerants if the nameplate is missing, etc is to check system components. For example, major system components should be marked both in color and print to indentify the refrigerant. TXV bodies should always be stamped or tagged for the refrigerant being used. 

AND BY ALL MEANS, AFTER GOING THROUGH THE TROUBLE OF IDENTIFYING OR REPLACING THE REFRIGERANT/OIL PLEASE BE SURE TO LABEL THE EQUIPMENT.:yes:


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