Originally Posted by ICYUNVME
To answer your third question the reason for there being so many different refrigerants is basically due to the phase out of older ozone damaging refrigerants by the EPA. Some of them are for high pressure systems some are for low pressure systems and some run at medium pressure. Some will require different oils in the compressor. R402 is an zeotropic blend meaning it has more than two refrigerants. The first thing I look at when choosing refrigerants to work with is the boiling point. The lower the boiling point the better cooling you will get. I have a universal EPA cert so I have no probs buying refrigerant but the average joe will not be able to get much more than automobile refrigerants and thats if you live in a state that sells it over the counter. R402 A is a very good blend to use and If I may suggest using the SUVA brand by dupont. We use it at work in our small 70 and 120 ton chillers and its a very stable refrigerant. It has very good glide properties and it doesn't mind low pressures. If you are going to go the route of zeotropic (more than 2) or azeotropic (blend of just 2) you need to make sure that you charge with liquid. due to the blend if you charge with gas you will not get a good distribution of the blend and it will change the whole refrigerant structure giving very erratic and sometimes catastrophic operation. Other than that as for buying them at this im at a loss because I buy from a shop up here in Wisconsin that will not even let you in the door without a license. Im not sure if you are liscensed or not. Hope i helped at least a little I know I got pretty indepth in my explanations.
Sorry i missed this thread Demon, i'd recommend 402 or 507, as ICYUNVME said you'll need to charge with a liquid, this can be done by simply turning the refrigerant container upside down, onto it's regulator.
If the refrigerant is a zeotropic or azeotropic then it's container will have support's around the regulator to allow you to do this.
Personally i think that you should use R290 (Propane), is got a good track record in SS's and it's also easy to get and cheap to