undersized liquid line

[SL82]

I was working on a 10 ton high temp potato cooler the other day. The liquid line is 5/8 for about 8 feet and tees off to 2 evaps with 5/8 line aswell, each at about 8 feet. The gas is 404 (request of the customer) When charging the system I couldnt clear the sightglass ended up putting way too much gas in and had to pull some out the next day. My question is If the liquid line is undersized would I see flashing in the sightglass up at the condensing unit?
I know an undersized liquid line causes pressure drop and therefore may cause flash gas at the txv but I dont see why you would see flashing upstream of the undersized liquid line where the pressure drop hasnt occurred yet? Im sorry I am not giving alot of info just more of a general question.

[Magoo]

Genrally with R404A you need to keep the condensing pressure at compressor at +40 C SDT, otherwise all hell breaks loose, if the sightglass after condenser is flashing intermitently the condenser control point is a problem, if glass is clear check actual line temp, should be in region of 5 ' C below condensing temp.., natural sub-cooling. Check vertical rise and length of liquid run as well. All loses will result in flashing before TEV, and system will under perform, the tev will hunt and go pear shaped. Remember keep SDT at +40 at compressor discharge.
Hopefully you liquid charged system that is really critical. R404A is ezio/ what ever tropic [ fraction ates ].
Hope this is helpful'.

magoo

[Gary]

Here's a mental trick I use to keep the tropes clear:

Theists are religious and atheists are not.
Zeotropes fractionate and azeotropes do not.

[nike123]

I was working on a 10 ton high temp potato cooler the other day. The liquid line is 5/8 for about 8 feet and tees off to 2 evaps with 5/8 line aswell, each at about 8 feet. The gas is 404 (request of the customer) When charging the system I couldnt clear the sightglass ended up putting way too much gas in and had to pull some out the next day. My question is If the liquid line is undersized would I see flashing in the sightglass up at the condensing unit?
I know an undersized liquid line causes pressure drop and therefore may cause flash gas at the txv but I dont see why you would see flashing upstream of the undersized liquid line where the pressure drop hasnt occurred yet? Im sorry I am not giving alot of info just more of a general question.


Flash gas could be caused because of sudden change in pressure in sight glass and they collapse after passing sight glass.
Therefore, sight glass is not perfect indication of system charge.
Check your subcooling.

[R. skiffington]

I'd be looking at your condensing pressure, as Magoo said, R404a goes a bit crazy if the condensing pressure is not stable, we work with R404a a lot and find it very reliable. If your cycling 1 or 2 cond fans you need to have the differential quite tight. Remember you can fit a lot of liquid in a 5/8 tube. Would be a lot easier to pin point if we new pressures and temps.