Heatcraft Refrigeration Products Air-Cooled Condensers none - Manual (Page 16)

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Head Pressure Setpoint
The.head.pressure.setpoint.potentiometer.is.adjustable.
from.90-250.psig ...A.typical.setpoints.are.from.170-200.psig ...
Note:..Very.low.setpoints.may.cause.the.fan.motors.to.run.
full.speed.continually.if.the.condenser.is.not.properly.sized ...
The.fans.will.turn.off.if.the.system.pressure.falls.below.the.
desired.setpoint .
Minimum Output
The.minimum.output.potentiometer.controls.the.minimum.
signal.sent.to.the.motor ...It.is.adjustable.from.0-60% ...If.this.is.
adjusted.to.60%,.the.motors.will.not.start.running.until.6V.is.
applied.to.the.motor ...The.motor.will.start.running.at.60%.of.
full.speed ...To.maximize.sound.reduction.and.energy.savings.
and.to.provide.the.most.stable.control,.it.is.recommended.
this.setting.be.left.at.0% .
Throttling range
The.throttling.range.potentiometer.controls.how.far.the.
system.pressure.must.deviate.from.the.control.setpoint.
to.generate.a.100%.output.signal.from.the.control ...It.
is.adjustable.from.10-100.psig ...The.throttling.range.
determines.how.quickly.the.motor.will.reach.full.speed.when.
detecting.a.change.in.head.pressure ...For.example,.if.the.
setpoint.is.200.psig.and.the.throttling.range.is.50.psig,.when.
the.system.pressure.is.below.200.psig,.the.fans.will.be.off ...
When.the.system.pressure.reaches.250.psig,.the.fans.will.be.
at.full.speed.(see.Chart.1.below) ..To.make.the.fans.ramp.
more.slowly.the.throttling.range.should.be.increased.
(see.Chart.2.below) ..To.maximize.sound.reduction.and.
energy.savings.and.to.provide.the.most.stable.control,.it.is.
recommended.this.setting.be.left.at.100.psig .
Motor RPM
Chart.1 ..Ramp.characteristics.with.
200.psig.setpoint.and.50.psig.
throttling.range
Motor RPM
Integration constant
The.integration.constant.switch.provides.ability.to.change.
controller.from.a.proportional.only.control.to.a.proportional.
plus.integral.control ..To.provide.the.most.responsive.system.
to.maintain.a.stable.head.pressure,.it.is.recommended.this.
setting.be.left.on.“fast .”
.
Reverse acting or direct acting mode of operation
The.reverse.acting/direct.acting.jumper.is.used.to.ensure.
the.controller.responds.correctly.to.maintain.desired.
head.pressure ...In.Direct.Acting.(DA).mode,.the.motor.
speed.increases.as.the.pressure.rises.above.desired.
setpoint ...For.proper.condenser.operation,.this.jumper.
MUST.be.in.Direct.Acting.(DA).mode ...Failure.to.ensure.J1.
jumper.is.in.direct.acting.mode.will.cause.the.system.to.
trip.on.high.head.pressure .
See.Diagram.#4.for.typical.proportional.pressure.control.
wiring .
Chart.2 ..Ramp.characteristics.with.
200.psig.setpoint.and.100.psig.
throttling.range