Carrier HS070-160 Manuel d'utilisateur télécharger pdf (Page 13)

NOTE: The control does not detect circuit breaker

failures. If a circuit breaker trips on the lead compressor

in a circuit, a

low

oil

pressure failure will be indicated;

on the other compressors, no failure will be indicated.

Checkout

P~-o~etiur~

(Codes 51-54)

Shut off the main

power to the unit. Turn on control power, then step

through the Quick Test to the proper compressor number

(i.e., failure code

step

CBT). Next, energize the

step. If the step works correctly, then the failure code

is due to:

. HPS

open

Ix-r

open

Mj~placcd

fu&

back wire from 2H5 strip to 293 strip

Ground wire and 24-volt feeds reversed on one or more

points on

2.t.3.

The 24-volt ground wire (brown)jumps

terminals 2, 4, 6 and 8. Feeds from compressors Al,

A2, Bl and 82 connect to pins I, 3, 5 and 7.

The processor closes the contacts between 255 ter-

minals 12 and

I to start the

cc3mprwsor.

(See Fig. 3.) The

safeties shown to the right of 2.15 must be closed for

power to reach the compressor

c<)ntroX

relay (CR 1) and

the feedback input (terminal

~I”I

2,13).

Failure of power to terminal

OLI

2J3 when contacts

255

I and I2 should be

closed

wilt

cause

a code 5

alarm.

Terminal 2 on 293 is the other leg

the compressor Al

feedback channel. It is connected to the 24-volt ground.

Code 59 and 60, Loss of Refrigerant Charge

A loss-of-

charge switch is connected to the high-pressure side of

the refrigerant system. The microprocessor monitors this

switch directly; if it opens, all the compressors in the

circuit will be locked off, the alarm will be energized and

the display code will appear when the alarm display is

accessed. To reset, use the manual reset method (move

the RUN/STANDBY switch to STANDBY, then back

to RUN).

Following are some possible causes for this alarm:

f,n\a>

RejPigerant

Charge

If the system refrigerant

charge is very low, the microprocessor will detect this

through the switch and indicate the error.

StzYtch

Failure

If the switch f&s open, the micro-

processor will detect this and indicate an error.

Wiring Error

If there is a wiring error that causes an

open circuit, the microprocessor

wikk

treat this as an open

switch and indicate an error.

Proc~esssr

Board Failure

If the hardware in the pro-

cessor module fails in a manner that the switch cannot

be read properly, an error may be indicated.

Code 61, No Cooler

Flow

The microprocessor con-

tains logic that prutects the cooler against loss of cooler

flow.The cooler entering and leaving water temperature

sensors are used for this purpose. The leaving thermistor

is located in the leaving water nozzle and the entering

sensor is located in the first cooler baffle space in close

proximity to the cooler tubes as shown in Fig. 4. When

there is no cooler water flow and the compressors are

operating, the leaving water temperature thermistor will

indicate no temperature change. But the temperature of

the entering water will drop rapidly and the entering

water thermistor will detect this. When the entering water

temperature drops to 5 F (2.8 C) below the leaving water

temperature,

alf

the compressors will stop and code

no. 61 will be displayed. To correct, use manual reset

method (after cooler water Row is resumed).

The error will be caused either by no cooler flow or

if the water is flowing in the wrong direction through the

cooler or if the thermistors have been interchanged.

Fig. 3

Compressor Al Control Wiring (Typical)

Code 63 and 64, Low Oil Pressure

A low oil pressure

switch is installed on the lead compressor in each circuit.

If the switch opens during operation of the compressor,

all the compressors in the circuit will be shut off, the alarm

light will be energized and the appropriate display code

shown. The switch will be bypassed for one minute during

start-up and for 45 seconds during normal operation. The

manual reset method must be used to reset this safety.

Possible causes for failure are:

Loss of’ Oil

Pres.sute

If the oil pressure is below 5

psig (34.5

6.9 kpa), the switch will open.

.S\i’itch

Failure

If the switch fails open, a failure will be

indicated.

Compwssor is

not

running.

wiring

Errur

If a wiring error exists that causes an

open circuit, an error will occur.

Pm~essov

Mod&

Faifure

If the hardware on the

processor module fails in a manner that the switch cannot

be read properly, an error may be indicated.

Code 65, Cooler Freeze Protection ~ If the leaving water

temperature is below 35 F (1.7 C) for a water chiller or

is 6’F (3.3 C)

below

the set point for brine applications,

all compressors wiil be stopped. This safety will auto-

matically reset when the water temperature is 6 F (3.3 C)

above the set point.

The causes for this failure are usually due to low cooler

flow, or extremely rapid load changes.

Code 66 and 67, High Suction Superheat

The micro-

processor contains the following logrc and

ifit

is satisfied,

all the compressors in the circuit will be stopped:

Suction superheat is greater than 75 F (4f.7 C), and

saturated cooler suction is

iess

than 55 F (12.8 C) and

these 2 conditions have been true for more than5 minutes.

To reset this, use the manual reset method.

Causes for this failure are:

IL);%’

R<fkigeranf

C’hwge

A low refrigerant charge

will.

not allow the correct amount of refrigerant to be fed to

the evaporator, which will result in a high superheat.

Pbuggcd

Filter Drier

If the liquid line filter drier

becomes plugged, it can result in not enough refrigerant

being fed to the evaporator, which results in a high super-

heat failure.

EXY Failure

If the EXV fails to open enough to feed

the proper amount of refrigerant, the error will occur.

EXV

Dviveu

Moduk Failure

the DSIO module

hardware that controls the EXVs fails, the

valve

will

not move.

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Carrier HS070-160 Manuel d'utilisateur Page 13

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