Replyyou can hook up gages and check against a press temp chart or get the fancy digitals and they will tell you. Time for new toys mabey.
Professional Member*
Hello - I'm new here. I'm an HVAC cross-over. Long awaited, now I think I'm ready and the opportunities exist. I'm decent with HVAC, I don't like to be hurried, I like to be careful and certain before throwing that switch. I like controls and logic problems. I like dirty hands.
I've been reading many posts here. Needless to say the naming of so many different refrigerants is daunting and leads me to wonder:
When you walk up to a reach in refrigerator at a restaurant for the first time and find that it's old, it's grimy, it smells bad, and it's warm - how do you now the gas is really the name plate stated R12? I mean surely some one has worked on this thing. Do you pull out the mystery gas and start anew?
That lead me to the follow-up: so how many recovery tanks are on your truck??? One for each refrigerant? Really?
Regular Guest
you can hook up gages and check against a press temp chart or get the fancy digitals and they will tell you. Time for new toys mabey.
Professional Member*
Digital guages don't really tell you what it is. They do have all the pt charts in them so its a little easier.
Also National refrigerants has "one shot " recovery tanks for about $40 if you need to recover a unpopular blend.
Professional Member*
The before mentioned methods will tell you what it is, most of the time. So once you know be a dear and grab a paint marker. :-)
Professional Member*
Thanks all. I'm familiar with TP charts but in AC it would be hard to miss the difference between R22 and R410a. But this world seems to have many refrigerants and refrigerant blends which depending on the operating temp have crossover values that I imagine would make it difficult. So I guess you're all saying that if it's way off the R12 TP chart then someone has either mixed or replaced and not left a tag.
Also appreciate the mention from "SBKold" about the recovery tanks. I have a reusable one for both R22 and R410a but they were both really expensive.
Professional Member
one thing to be wary of when you are looking at units to determine the refrigerant: make sure it has the proper charge weight in it. otherwise it will throw off your reading.
Professional Member
Originally Posted by demidos89
Not really.
As long as there is a quantity of liquid in the unit, the saturation temperature will be correct.
Professional Member
i mean when its nearly out of gas. but at that point i guess it would be best to pull the charge and update if possible.
Professional Member
After you know what the plate says, verify...verify. Check the condenser sticker for oil type. If a TXV, check it's marking for what it's set up for. Look for any markings (with a "sharpie" or any added stickers) on or around the condensing unit that might cue you in on whether/what refrigerant someone used in it. Lastly...system pressures. Do they match what you'd expect for that nameplate refrigerant? Of course, if it's low due to a leak, this pressure verification won't really do any good. Doing a "static" pressure reading of system is most accurate, there's gotta still be some liquefied stuff still in the sytem for that to work.
The most common three refrigerants I saw were R134A, R22 & R404A - so tank for each of those. Then I kept an empty, undedicated (yet) tank on the truck for "whatever" I might run in to.
So....4.
New Guest
If the label remains R-12, odds are it is a 12 drop in. 401 (MP-39) or 409.
Professional Member
Oh yeah. For sure.
Professional Member
also some people replace it with R 414b however it probably wont last long due to the fact it contains R22
Regular Guest
Why wont it last long? (414b)
Global Moderator
Have you priced Hot Shot lately ? That's why it won't be around long.
Professional Member
Phase out
Regular Guest
Gotcha, no don't use hot shot.
Regular Guest
You introduced this thread by implying that the old R-12 system was short on gas. Chances are you are going to have to pull the remaining charge to fix it (for smaller systems, anyway, there is no place to pump it down). At that point - you have an empty R-12 system. It doesn't really matter what the interim gas was - use your favorite R-12 alternative to get it running again.
Some other points: If you don't know what it is, that makes disposal a real problem. You can get an EZ One Shot cylinder (thanks for the plug, by the way) but you have to label it with whatever you put into it. So from a "fix the system:" point of view it doesn't matter, but from a "how do I get rid of it" point of view you still need to know. Also, when checking the ID of a blend against the PT chart - if you have fractionated the blend when it leaked (meaning you lost mostly vapor when the system was off) then the PT chart doesn't work anymore. Another monkey wrench in the process.
The only real way to know is to get a sample analyzed - and there is NO economic incentive to do that. Bottom line - hope that the courteous and professional tech who was there before you labeled the system properly (and think about that before you leave the job yourself...).
Professional Member*
That was well stated and helpful, thanks!
Your response makes me wonder regarding "how do I get rid of it" point of view. If I'm filling a tank and don't know what it is at the time, but later take a saturated temp reading after tank ambient stabilization, and match it to........something on a PT chart. Am I at financial risk when I bring the tank back to my distributor? I mean if they determine that it's a mix or some other refrigerant blend. I was told they burn it if it doesn't match, end of story. But I've also heard they can now "fractionate it" to separate all the different individual refrigerants via fractional distillation as no2 heating oil is separated from crude. Is this true?
I'll be done in just a few minutes...
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