Heatcraft Refrigeration Products Air-Cooled Condensers none - Manual (Page 5)

5
Typical Arrangements
Figure.1.illustrates.a.typical.piping.arrangement.involving.a.
remote.condenser.located.at.a.higher.elevation,.as.commonly.
encountered.when.the.condenser.is.on.a.roof.and.the.compressor.
and.receiver.are.on.grade.level.or.in.a.basement.equipment.
room ..
.
In.this.case,.the.design.of.the.discharge.line.is.very.critical ...If.
properly.sized.for.full.load.condition,.the.gas.velocity.might.be.
too.low.at.reduced.loads.to.carry.oil.up.through.the.discharge.
line.and.condenser.coil ..Reducing.the.discharge.line.size.would.
increase.the.gas.velocity.sufficiently.at.reduced.load.conditions;.
however,.when.operating.at.full.load,.the.line.would.be.greatly.
undersized,.and.thereby.create.an.excessive.refrigerant.pressure.
drop ..This.condition.can.be.overcome.in.one.of.two.following.
ways:.
.
. 1 ..The.discharge.line.may.be.properly.sized.for.the.desired..
. . pressure.drop.at.full.load.conditions.and.an.oil.separator.
. . installed.at.the.bottom.of.the.trap.in.the.discharge.line.
. . from.the.compressor ..
.
. 2 ..A.double.riser.discharge.line.may.be.used.as.shown.in.
. . Figure.2 ..Line.“A”.should.be.sized.to.carry.the.oil.at.minimum..
. . load.conditions.and.the.line.“B”.should.be.sized.so.
. . that.at.the.full.load.conditions.both.lines.would.have..
. . sufficient.flow.velocity.to.carry.the.oil.to.the.condenser ..
.
For.more.complete.information,.refer.to.the.ASHRAE.Handbook.
on.Systems .
Figure 1
Figure 2
Notes:
1 .. All.oil.traps.are.to.be.as.short.in.radius.as.. .
. possible ..Common.practice.is.to.fabricate.the.. .
. trap.using.three.90.degrees.ells ..
2 .. Pressure.relief.valves.are.recommended.at.the.. .
. condenser.for.protection.of.the.coil ..
.
3 .. A.drain.line.check.valve.is.recommended.for.. .
. applications.where.the.condenser.may.be.at.a.. .
. lower.temperature.than.the.receiver .
Installation, Refrigerant Piping
Install.piping.according.to.standard.accepted.refrigeration.
practice ..The.following.recommendations.should.be.adhered.to:.
. 1 .. See.Tables.1.and.2.for.discharge.and.liquid.. .
. . drain.line.sizes.for.remote.condenser..
. . connections ..
.
. 2 .. Use.only.refrigeration.grade.copper.tubing ..
.
. 3 .. Soft.solder.joints.are.not.acceptable ..
.
. 4 .. Put.dry.nitrogen.through.lines.while.brazing ..
.
. 5 .. Do.not.leave.dehydrated.piping.or.components.
. . open.to.the.atmosphere.any.longer.than.is.
. . absolutely.necessary ..