[Vlad]

What I found about R290 is bits and pieces here and there. There is no even an accepted name for this refrigerant. They are R22a, R290, Propane, all kinds of "greens..." and "enviro..." etc. Also there is a bunch of blends of propane and butane.

The technical details are also differ from site to site. If we could share our own experience and known info this would help to summarize list of properties.

What I found (again some info can be controversial) is

1 R22a = R290 = pure refrigerant grade propane, which is dry and scent is added for safety reason.

2 R22 PT chart almost = propane PT chart. We can simply use R22 Pt chart for simplicity and usually they are more detailed.

Sorry I wanted to say R22a PT chart looks like R290 chart. But R290 chart is more complete.

3 R22 Cap tube when used with propane must be 16-20 % longer. Because propane is easy to push through the cap tube (it is like water VS alcohol)

4 Superheat MUST be in 20F zone because propane is tend to condense and compressor is getting liquid in suction line. This can dramatically shorten life of compressor.

5 I found that many recommend liquid line-suction line HX because it helps maintaining superheat and increases COP (substantially compare to R22)

6 Legal charge for indoor use in Canada 350 gram.

7 If you want to use BBQ propane, it must be dry. If you use liquid line filter/dryer it will remove moisture but WILL also REMOVE the smell from propane.

8 There is controversial information about COP. Some people say it is much more efficient compare to R22 some say COP differ but not significant.

Lets put together as much info as possible about R290 and see what we can do.

Also I wanted to add about charging system. Do not charge any refrigerant as a vapor because you will add non condesable gases like nitrogen into your system. Always charge liquid into suction line while compressor is running. Just be careful and meter refrigerant with your gauges.