Quote Originally Posted by jaysephus
The other things wanting to share this liquid is the cold storage intercooler and the cold storage recirculator vessel. So the other thing I can watch for is when the vessels are calling for liquid...
Not entirely... read below.

Quote Originally Posted by jaysephus
Would it make sense to insulate this high pressure liquid line? I don't think so but the SullAir manual says that to do that in cause of erratic temps. It's high pressure warm liquid so I don't see that working.
The Sullair manual IS correct. Think about it like this... If the liquid line is cooler than the ambient air temperature, which way does heat flow? It flows into the cooler liquid line. If the liquid line comes straight from the receiver it does not have any subcooling therefore the liquid can begin to flash off. The first compressor gets all of the liquid it needs, while the subsequent compressors only have access to the remaining liquid. As the liquid continues in length the remaining compressors get less and less liquid.

Then if for some reason the oil cooling load on one compressor decreases there is more liquid available for the remaining compressors downstream. If the Jordan valve is stroked all the way open when that occurs it has to throttle back. If it can't do this fast enough a sufficient volume of liquid may get into the compressor causing the alarms.

The flash gas in the liquid line is also caused by changes in pipe elevation. When a high pressure liquid line is installed to run vertically upwards the change in elevation reduces the liquid pressure due to static head penalties. This can be compounded installing a liquid line that is too small in diameter. This causes an increase in friction loss due to flow.

So... it is necessary to insulate a properly sized high pressure liquid line.

If you ever hear someone saying a 3/4" liquid line is sufficient for any reason you should ask them: based on what? And see what their answer is.

There are reason for why things work. Unfortunately, these are also the same reasons why things don't work.