R-12 Dorm Fridge conversion to 134A???

[techops]

I have a bunch of dorm fridges around the building that I take care of and have a bunch of these r 12 fridges that are in great shape but are in need of refrigerant. Is there a preferred method to converting these to 134A?

ANy help is appreciated!!!!

[gerryboy00]

clic the search icon up here then search for "conversion r134a"

[johnl45]

134A is a poor choice for a conversion from R-12.

[Diceman]

I have one of them thingys in my office. Ran low on gas, sucked out the R-12, dumped in 409-A, works good for many years now. 409 is a good, simple drop for units like that, not really worth a big conversion.

[James 3528]

Originally posted by Diceman
I have one of them thingys in my office. Ran low on gas, sucked out the R-12, dumped in 409-A, works good for many years now. 409 is a good, simple drop for units like that, not really worth a big conversion.

Dorkster

R 416-A is even better.

[ed0612]

conversion is not worth it. Drop in replacements for R12,
I've used 409,hotshot is another.Econically 409 probaby is
the best choice for the money.ed0612

[techops]

Thanks for the suggestions. I think I am going to give hot shot a try being that one of our other shops has a can. What is the difference between 416A and 409A. Which do you prefer? Will et you know how I make out,..,.

[Diceman]

The diff between 416 and 409 is this:
416 is made on an old tobacco plantation in the south. They still use slaves in the factories too. It comes in a rusty, old can without a lable on it. Sometimes the can is empty when you buy it, sometimes it has propane in it instead of freeezone. Ya just never know for sure down there.
On the other hand, 409 is made up north here in ultra high tech labs supervised by retired German rocket scientists. Completely pure and non toxic. You can even drink it if your truck breaks down in the desert. If you run out of gas on the freeway, just dump some 409 in the tank. It's that good.
Anyway, you make the choice.

[ed0612]

Hotshot & 409 have a higher discharge temp than R12. I think I read 406a is about the same

[James 3528]

Advantages of Aspen R-416A vs. R-22 Based Blends (R-401A, R-409A, R-414B)
R-416A has lower discharge pressures and temperatures
R-416A has lower glide- it is classified as a NARM (Near Azeotrope)
R-416A exhibits lower fractionation, it can be topped-off without loss of performance
R-416A has better compatibility with the materials of construction in systems designed for R-12
R-416A has a lower global warming and lower ozone depletion potential
R-416A optimizes compressor performance: quieter, longer life with reduced current draw

[Diceman]

But I ain't worried bout non of dat crap.
I just like the nice light brown can 409 comes in.

[James 3528]

That is another thing. 416 comes in a neon yellow/green can that is cool and can not be mistaken for HP 80

[Diceman]

Neon yellow and green....OK, I'm in, I'll try it, even if it is made in southern factories by slaves.

[kim]

414 is the best med temp R12 replacement. You can't tell the difference with a pressure gage and thermometer. Don't tell anybody, but it mixes with R12 easily. (I have never mixed any freons myself, but that is what I hear.)
Least glide
Least discharge temp, etc compared to the rest of the 400. It costs a little more and does not do low temp very well though.

[scottb63]

the disadvantage to 416 is you have to convert to POE, no small task in a mineral oil system (PITA)

[James 3528]

Originally posted by scottb63
the disadvantage to 416 is you have to convert to POE, no small task in a mineral oil system (PITA)


No oil change is required under normal operating conditions.

[u-r-in]

If they leak how can they be running great?? use 409A but check compressor amp draw when charging. Stop charging at compressor full load amp. charge is about 80% of R-12 charge.

[kim]

Don't get too hung up on amp draw there UR. Subcool, superheat, coil DT, discharge temp and play apart. I like to go with superheat first at design load and coil DT first when it is pulling down. But I never start a new system without an amp clamp on the compressor.

[u-r-in]

On a small dorm fridge which is a critical charge unit ie cap tube I would not charge by subcooling or superheat. I would weigh in charge and not overload compressor. can check frostline on suction line, clean coils, all else is probably more time consuming than benificial.

[kim]

I would charge by evap TD, 10 degrees, and use amp draw as a secondary measure to check for possible system errors. Check as close as possible to the actual thing you want to get.

[Diceman]

use 409, get the suction to about 10-15 psi, check condenser with hand, feel heat slowly disipate as it moves down the condenser, forget the rest of that jazz.

[kim]

I would just shoot a little freon in it and check it tomarrow. Just adding a tap cost more than the box is worth, but sometimes you do have free time to mess with stuff.

[beenthere]

I'd buy a new dorm frig and junk the old POS.

[mardoman]

Is R 416 U.L. listed?

Years ago I bought "Hotshot" used it and went to purchase more but, wholesaler pulled it from shelves because it wasn't U.L. listed.

That reminds me that the same "Dupont" wholesaler didn't have MP-39 in stock, so I went to another wholesaler and
purchased R-409A and have been using it since.

Works fine and lasts a long time. Head pressure runs a little high. Keep condenser coil clean.

Most cap tube systems will need charge weighed in @ 80-90%.
TXV systems use recievers and usually sightglasses.
I weigh in charge and usually clear the sightglass

[kim]

Target has them on sale for $45.