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marksmith970
13-08-2008, 01:11 PM
What would happen to the capacity of a condensing unit if you 1/2" Instead of 5/8" Suction and 3/8" instead of 1/2" for the pipe run which is about 25m? The Condensing Unit is a Maneurop MCZC054MTA02G. The units are outside about 3m high.

coolments
13-08-2008, 01:31 PM
It would definetley reduce but by how much I dont know.
High discharge pressure, evap being starved of enough liquid, longer run time, poor performence and excessive wear on the plant are a few of things that will occurr. you may get it to work but not as it should.

750 Valve
13-08-2008, 01:46 PM
Well assuming its not a capillary system and that the original pipe sizing is correct then you'll see a lower suction pressure and a pressure drop between evap and comp in the suction line, this will increase at higher loads. You will experience longer run times due to this PD and a lot more energy input to do the work, so if your unit is borderline on the sizing it may struggle a max design conditions. On the liquid side you may also experience a pressure drop which if you don't have a good amount of subcooling can end up flashing off liquid and decreasing your capacity as well.

old gas bottle
13-08-2008, 02:33 PM
why would you even consider doing it ? its a long pipe run and if anything they need to go up a size not down and fit a oil seperator , why look for trouble.:eek:

The MG Pony
13-08-2008, 10:17 PM
this is a stupid thing to even consider IMO are you qualified? Never undersize your piping, the reasons given here should be evidence enough!