Heatcraft Refrigeration Products Air-Cooled Condensers none - Manual (Page 6)

6
Electrical Wiring
The.electrical.installation.should.be.in.accordance.with.National.
Electrical.Code,.local.codes.and.regulations ..Proper.overcurrent.
protection.should.be.provided.for.the.fan.motors ..
.
All.standard.motors.have.internal.inherent.overload.protectors ..
Therefore,.contactors.can.be.used.instead.of.starters.requiring.
thermal.protectors,.eliminating.the.problem.of.furnishing.the.
proper.heating.elements ..
.
All.air-cooled.condensers.are.furnished.with.either.single-phase.
or.three-phase.fan.motors.which.are.identified.by.the.unit.
dataplate ..
.
Electrical.leads.from.each.motor.terminate.at.the.unit.junction.
box ..Field.connections.must.be.made.from.these.leads.in.
accordance.with.local,.state.and.national.codes ..
.
Three-phase.motors.must.be.connected.to.three-phase.power.of.
voltage.to.agree.with.motor.and.unit.dataplate ..
.
The.motors.are.wired.into.a.common.junction.box ..Where.
fan.cycling.is.furnished.and.factory.installed,.the.motors.are.
completely.wired.through.the.control.and.to.the.contactors ...The.
motors.must.be.checked.for.proper.rotation ..Be.sure.to.check.that.
motor.voltage.and.control.connection.agree.with.electric.services.
furnished .
Discharge Lines
The.proper.design.of.discharge.lines.involves.two.objectives:.
1 .. To.minimize.refrigerant.pressure.drop,.since.high.. .
pressure.losses.cause.increased.compressor.. . .
horsepower.per.ton.of.refrigerant .
2 .. To.maintain.sufficiently.high.gas.velocity.to.carry.oil..
. through.to.the.condenser.coil.and.receiver.at.all.loading..
. conditions .
Table 2. Condensing Temperature Correction Factor
Condensing
Temperature
Discharge Line
R-22 R-502 R-404A R-507 R-407C R-410A R-134A
90 0 .88 0 .91 0 .922 0 .924 0 .872 0 .889 0 .882
100 0 .95 0 .97 0 .974 0 .975 0 .957 0 .963 0 .961
110 1 .04 1 .02 1 .009 1 .005 1 .036 1 .032 1 .026
120 1 .10 1 .08 1 .026 1 .014 1 .009 1 .096 1 .078
130 1 .18 1 .16 1 .043 1 .024 1 .182 1 .160 1 .156
Table 1. Tons of Refrigeration
Line Size
Type L Copper
OD
Discharge Line Drain Line
Velocity 100 FPM Refrigerant
R-22 Sat. Suction Temp (°F) R-404A/R-507 Sat. Suction Temp (°F)
-40 0 40 -40 0 40 R-22 R-404A
1/2 0 .75 0 .8 0 .85 0 .56 0 .63 0 .7 2 .3 1 .5
5/8 1 .4 1 .5 1 .6 1 .0 1 .2 1 .3 3 .7 2 .3
7/8 3 .7 4 .0 4 .2 2 .7 3 .1 3 .4 7 .8 4 .9
1-1/8. 7 .5 8 .0 8 .5 5 .5 6 .3 7 .0 13 .2 8 .3
1-3/8 13 .1 14 .0 14 .8 9 .6 10 .9 12 .1 20 .2 12 .6
1-5/8 20 .7 22 .0 23 .4 15 .2 17 .2 19 .1 28 .5 17 .9
2-1/8 42 .8 45 .7 48 .5 31 .4 35 .6 39 .5 49 .6 31 .1
2-5/8 75 .4 80 .4 85 .4 55 .3 62 .8 69 .5 76 .5 48 .0
3-1/8 120 .2 128 .2 136 .2 87 .9 99 .8 110 .5 109 .2 68 .4
3-5/8 178 .4 190 .3 202 .1 130 .5 148 .1 164 .0 147 .8 92 .6
4-1/8 251 .1 267 .8 284 .4 183 .7 208 .4 230 .9 192 .1 120 .3
Source:..ASHRAE.Refrigeration.Handbook:
1 .. Line.sizes.based.on.pressure.drop.equivalent.to.1°F.per.100.equivalent.feet .
2 .. Values.in.Table.are.based.on.105°F.condensing.temperature ...Multiply.Table.capacities.by.the.factors.in.Table.2.for.other.condensing.temperatures .
3 .. If.subcooling.is.substantial.or.the.line.is.short,.a.smaller.line.size.may.be.used ..Applications.with.very.little.subcooling.or.very.long.lines.may.require.larger.sizes
WARNING:..There.may.be.more.than.one.source.of.electrical.current.in.this.unit ...Do.not.service.before.disconnecting.all.power.supplies .