View Full Version : r-12rules
07-05-2004, 08:43 AM
hi, thanks for reply i am working on an old unit that has not run in approx. 10years this is a cooler that has two seperate units on it, i was told too make it into a freezer
the one unit has r12 and is running but the other one has a leak i need too find the leak and fix then charge with 401b i dont think the unit with r12 will handle the load it is now running at -6 not sure how this will turn out. i did get evap fan running. thanks ken
Ken, One of the first things you have to ask is... Will the old box insulation materials handle the temps you need for a freezer? The insulation materials are different R values. Is this a well sealed box? Does it have an insulated floor? Is the floor concrete that will heave with the moisture/freeze-refreeze? How about a door frame heater?? Got a crowbar handy?
Next... how much will it cost to convert your evap coils to a freezer coil with defrost? Are you going to use electric heaters? Hot gas defrost? If you use hot gas will the age of the coil be a factor? YES!
Since your other post says you have r12 systems for a cooler you need to check if your condenser system can handle LOW TEMP. You will find it is for medium temp/high temp now. TOSS'EM
If the system hasn't been started up in 10 years that would make this box at least 15 or more years old.
Remove all of the refrigeration components and trash them. Start fresh if you want a box that will give your customer years of pleasure, install a good 404A condenser and properly sized evap coils with defrost. You can install a new service door with door frame heaters. Don't forget to calculate the load for the old cooler insulation materials and seal the air leaks.
07-05-2004, 03:34 PM
Take lusker's advice and go with new R404A units
storage box and storage freezer of same size are fairly close to same btu requirements
compressor needed for freezer about 3 times larger for this btu
assume box requires 56,000 btuh
9RS3-0765 MT R12 = 56,000 btuh
9RS3-0675 LT R12 - 20,000 btuh
where does that put you (beyond the pitfalls lusker mentions)
07-05-2004, 03:43 PM
hi, i am almost sure that at one time this cooler was a freezer then the co. got anotherone larger then this one was changed too a cooler and now we have changed hands and the new co. wants too make these changes without a big expense go figure anyway the defrost is heaters the box is well insulated and door does have a heater in it.
There in lies your biggest problem.
If was a freezer and nothing has changed except for the r12 then put a blend of your choosing in it and stand back.
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