Carrier GY Instrucciones de operaciones descargar pdf (Pagina 13)

Actual start-up

IMPORTANT:

• Commissioning and start-up of the chiller must be

supervised by a qualified refrigeration engineer.

• Start-up and operating tests must be carried out with a

thermal load applied and water circulating in the

evaporator.

• All set point adjustments and control tests must be carried

out before the unit is started up.

• Please refer to the controls manual for the unit.

a. Start up the unit.

b. Check that all safety devices are satisfied, paticularly the

high pressure switches.

For this purpose:

- Stop the condenser fans.

- Operate the machine until the high pressure switch

trips and verify that the pressure does not exceed the

cut-out value of 2900 kPa.

- Using the control point as a reference, verify the

correct operation of the unit.

Electromechanical control

Multi-step thermostat

This consists of a series of load switches actuated by the

pressure developed inside a temperature sensing bulb, installed

in the cooler inlet.

Before replacing the bulb, half fill the well with a heat

conducting sealing compound. Replace the sensor in the well

recess. The thermostat is factory-set to control from the return

water temperature through a cooling range of 5.6 K.

The sequence switches are factory-calibrated and sealed

and should not need any field calibration. Two steps on

30GV and 30GY 020 to 035 and three steps on 30GV and

30GY 044 to 059 are available.

WARNING: Alteration of factory settings other than the design

set point, without the manufacturer's authorization, may void

the warranty.

If a different return water range or leaving water control is

specified, or if brine is to be used, the controller must be

changed. Consult your local Carrier representative for the

proper control.

Design set point adjustment (three-step thermostat)

Legend:

A - Differential between stages

B - Differential on one contact

R, Y, B - Thermostat contact reference

O - Open contact

F - Closed contact

Set point adjustment

When the unit is ready for operation, insert a small screwdriver

in the adjusting slot to turn the dial (the dial may also be turned

by hand). Rotate the screwdriver, until the design set point for

the installation appears directly under the pointer. Insert a

thermometer in the return water connection and allow the unit

to run through a complete cycle. When switch No. 1 opens, the

last capacity step appears directly under the pointer. Read the

temperature. If it is not the same as the dial reading, it can be

compensated by shifting the control point slightly.

NOTE: Do not force the dial past the stop. This could cause

loss of the control point and damage the instrument.

Set point adjustment

Control pressostats

Low pressure switch

Switches the unit off, if the evaporating temperature is too low:

Cut-out: 200 kPa

Cut-in: 350 kPa

Condensing pressure switch (2-speed option)

Energizes and de-energizes the second fan speed as a function

of the condensing pressure:

Cut-out: 1700 kPa

Cut-in: 1090 kPa

Set point

RY3

RB3

RY2

RB2

RY1

RB1

RY3

RB3

RY2

RB2

RY1

RB1

Temperature

drop

Temperature

rise

Calibrated dial

Stop

Pointer

Adjusting slot

Set points

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 19 20

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Carrier GY Instrucciones de operaciones Pagina 13

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