Carrier HS070-160 User Manual

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Page 1

30HR,HS070-160

HEATING & COOLING

Flotronic Plus Reciprocating Liquid Chillers

Controls Troubleshooting Guide

Alf Model E Units Have Microprocessor Controls

and Electronic Expansion Valves

CONTENTS

Page

SAFETY

FLOTRONIC PLUS CONTROL SYSTEM ..... l-4

Generat ..................................... 1

Features .....................................

. PROCESSOR MODULE ...................

l LOW-VOLTAGE RELAY MODULE .........

. EXV

VALVE) DRIVER MODULE ...............

. KEYBOARD AND DISPLAY MODULE .....

. ELECTRONIC EXPANSION VALVE ........

l THERMISTORS ...........................

. CAPAClTY CONTROL ....................

CONTROL SEQUENCE .....................

Off Cycle ....................................

Start-Up ....................................

Capacity Control ............................

l SEQUENCE ...............................

Unit Shutdown ..............................

Complete Unit Stoppage

Single-Circuit Stoppage .....................

Lag Compressor Stoppage ...................

Restart Procedure ...........................

l GENERAL POWER FAlLURE ..............

l BLOWN FUSE

DISCONNECT ............................

l LOW WATER TEMPERATURE

CUTOUT..................................

l AUXILIARY INTERLOCK .................

l OPEN CONTROL

. FREEZE PROTECTION ....................

a HIGH-PRESSURE SWITCH ................

l LOSS OF CHARGE SWITCH ...............

. COMPRESSOR DISCHARGE

TEMPERATURE SWITCH .................

. OIL SAFETY SWITCH .....................

CONTROLS OPERATION .................. .5-l I

Accessing Functions and Subfunctions. ......

Qisplay Functions ...........................

a SUMMARY DISPLAY .....................

. STATUS FUNCTION ......................

. TEST FUNCTION ........................

Programming Functions

SERVlCE

l SET POINT FUNCTION ..................

l SCHEDULE FUNCTION ..................

TROUBLESHOOTING .....................

Checking Display Codes ....................

l OPERATING MODE CODES ..............

. ALARM CODES

Quick Test .................................

Electronic Expansion Valves ................

l CHECKOUT PROCEDURE ...............

l EXV OPERATION ........................

Thermistors ................................

l LOCATION ..............................

l SENSOR REPLACEMENT ................

Modules ....................................

CONSlDERATlONS

(ELECTRONK

POWER FEED

EXPANSION

CIRCUlT

................ 1

.....................

FUSE ..........

....................

FUNCTION ....................

.........................

4,5

12-26

12 12

14 19

22 22

SAFETY CONSIDERATIONS

Installation, start-up and servicing of this equipment can be hazardous due to system pressures, electrical components and equipment location.

Only trained, qualified installers and service mechanics

2 2

2 2 3 3 3

4 4

5 5

5 5 5

should install, start-up and service this equipment.

When working on the equipment, observe precautions in the literature, tags, stickers and labels attached to the equipment and any

l Follow all safety codes.

Wear safety glasses and work gloves.

l Use care in handling, rigging and setting bulky

other

safety precautions that apply.

equipment.

l Use care in handling elcetronic components.

ELECTRII~ SHOCK HAZARD.

Open all remote disconnects before

servicing this equipment.

This unit uses a micreprocessor-based electronic control system.

190

not use jumpers or other tools

to short out components, bypass or otherwise depart from recommcndcd procedures. Any short-to- ground of the control board or accompanying wiring may destroy the electronic modules or electrical component.

FLOTRONIC PLUS CONTROL SYSTEM

General

feature microprocessor-based electronic controls and an

electronic expansion valve (EXV) in each refrigeration circuit.

The Flotronic Plus control system cycles compressors

and compressor unloaders to maintain the selected leav-

ing water temperature set point. It automatically positions the EXV to maintain the specified refrigerant superheat entering the cylinders of the compressor. Safeties are continuously monitored to prevent the unit from operating under unsafe conditions. A scheduling function, programmed by the user, controls the unit occupied/ unoccupied schedule. The control also operates a Quick Test program that allows the operator to check

input and output signals to the microprocessor.

The control system consists of a processor module (PSIO), low-voltage relay module (DSIO), electronic expansion valve (EXV), EXV driver module (DSIO),

keyboard and display module (HSIO) and thermistors to

provide analog inputs to the microprocessor. The soft-

ware resides in the PSIO.

The 30HR,HS Flotronic Plus chillers

Page 2

Features

The 30HR,HS control panel is shown in

Fig. 1. PROCESSOR MODULE - This module contains the

operating software and controls the operation of the

machine. It continuously monitors information received from the various temperature thermistors and communicates with the relay module to increase or decrease the active stages of capacity. The processor module also controls the EXV driver module, commanding it to open

or close each electronic expansion valve in order to maintain approximately 20 F of superheat entering the cylinders of each of the

Iead

compressors, Information is

transmitted between the processor module and the relay

module, EXV driver moduIe and keybuard display

module through a 3-wire communications bus.

EXV (ELECTRONIC EXPANSION VALVE) DRIVER MODULE -- The EXV driver module operates the electronic expansion valves (based on commands from the processor) and monitors the status of the

oi1

pressure

switches and the refrigerant Ioss of charge switches.

If the loss of charge switch opens due to a low refrigerant charge, the EXV driver module detects a zero voltage condition in the loss of charge switch electrical

circuit and communicates this information to the processor module. The processor module immediately shuts down all compressors in the affected refrigeration circuit.

During operation, if the EXV driver module detects

zero voltage in the oil pressure switch electrical circuit for 45 consecutive seconds (due to an open oil pressure switch), it communicates this information to the processor module. The processor module immediatelvshuts down ali compressors in the affected refrigeration circuit. At start-up, if the oil pressure switch has not closed by the end of a 60-second time period the EXV driver module senses this and the processor module immediately shuts down all compressors in the affected refrigeration circuit.

If a shutdown occurs due to loss of

cftarse

or low oil pressure, the EXV driver module communicates this to the processor module and the processor module locks the compressors off in the affected refrigeration circuit.

The proper fault code(s) will appear on the display

whenever a safety switch opens.

KEYBOARD AND DISPLAY MODKLE - (Fig. 2) This device consists of a keyboard with Cr function keys, 5 operative keys, 12 numeric keys (0 to 9, 11 -) and an alphanumeric g-character LCD. Key in Table

usage ii;

explained

.:.

I - Keyboard/Display Module 2 -

Control Power ON Light 3 - RUN/STANDBY Switch

4 -

Discharge Pressure Gage 5 - Suction Pressure Gage Valves

6 -

Suction Pressure Gages 7 - Discharge Pressure Gages 8 - Compressor ON Lights

9 - Control Circuit Fuses

Alarm Light

Fig. 1 - Control Panel

Valves

LOW-VOLTAGE RELAY MODULE -- This module closes contacts to energize compressors, solenoid valves and unloaders. It also senses the condition of the com-

pressor safeties and transmits this information to the

processor module.

Table 1 - Keyboard and Display Madule

FUNCTION

KEYS

SCHD

OPERATIVE

KEYS

EXPN

CLR

ENTR

Key Usage

LOSE

Status - Displayjng diagnostic codes and current operating information about the machine

Quick Test - Checking inputs and outputs for proper operation

History - This key appears on the keyboard, but is not used on the 30HR,HS

Service - Entering specific

unit configuration information

Set Point - Entering operating set points and day/time

information Schedule - Entering occupied/

unoccupied schedules for unit operation

Expand Display - Displaying a non-abbreviated expansion of

the display

Clear - Clearing the screen of all displays

Up Arrow previous display posItIon

Down Arrow - Advancing to next display position

Modei

USE

Rtjturnipg to

E machines

Page 3

Each function has one or more subfunctions as shown At initial start-up the valve position is initialized to 0. in Table 2. These functions are defined in greater detail After that, the microprocessor keeps accurate track of the in t K Controls Operation section of this book.

valve position in order to use this information as input for the other control functions.

The control monitors the superheat and the rate of change of superheat to control the position of the valve. The valve stroke is very large; this results in very accurate control of the superheat.

The electronic expansion valve is also used to limit the maximum saturated suction temperature to 55 F (12.8 C) to keep from overloading the compressor during high cooler water temperatures. This allows the unit to start with very warm water temperatures.

THERMISTORS ~ The electronic control uses 7 thermistors to sense temperatures used to control the operation of the chiller. Sensors are listed in Table 3.

Fig. 2 - Keyboard and Display Module

ELECTROWIC EXPANSION VALVE ~ The micro-

processor controls the electronic expansion valve through the EXV driver module. Inside the expansion valve is a linear actuator stepper motor. To control the stepper motor’s position, the thermistor in the cooler and the thermistor in the lead compressor in each circuit are used to maintain a 20 F (1 I C) difference. Because the compressor sensor is after the compressor motor, which adds approximately 15 F (8.3 C) superheat, the 20 F (1 I C) control temperature results in

U”F

to 5 F (2.8 C) superheat leaving the cooler. This improves the performance of the cooler.

CAPACITY CONTROL ~ The control cycles compressors and alternately loads and unloads cylinders to give capacity control steps as shown in Table 4. The unit controls leaving chilled water temperature. Entering water temperature is used by the microprocessor in determining the optimum time to load and unload, but is not a control set point.

The chilled water temperature set point can be automatically reset by the return temperature reset or space and outside air temperature reset features.

Table 2 - Function and Subfunctions

FUNCTIONS

Page 4

Table 4 - Capacity Control Steps

UNIT

:ONTR

30HR

STEPS

30HS

070

080

090

100

110

120, 160

140

NOTE: Circuits and from front of unit.

Table 3 - Thermistors

SEQUENCE A

?r Cylinders

Cap.

EiiqTm-

Compr

10 12 14 16

10 12 16 18

1: ::

:; hi

10 12 16

22 24

10 12 16

14.3

42.9

57.2

71.2

85.7

100.0 4

25.0

50.0

62.5

75.0

87.5

100.0

22.2

44.4

55.5

66.7

88.8

100.0 4

20.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0 4

18.2

36.3

45.4

54.5

72.7

81.8

90.9

100.0 4

16.6

33.3

41.6

50.0

66.7

75.0

91.6

100.0 4

19.0

38.0

47.6

57.0

69.0

78.6

90.4

100.0

compressors designated from ieft to right when viewed

Cap.

2&.6

42.9

57.2

71.2

85.7

00.0

25.0

50.0

62.5

75.0

87.5

00.0

22.2

44.4

55.5

66.7

88.8

‘00.0

20.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

18.2

36.3

45.4

54.5

63.6

72.7

90.9

t 00.0

16.6

33.3

41.6

50.0

66.7

75.0

91.6

100.0

19.0

38.0

47.6

57.0

69.0

78.6

90.4

100.0

ENCE 3

er Cylinders

zlzqxi7

rot.

10 12 14

1: 13 14

14 16 18

12 14

20 22

10 12 16

iif ::

22 24

Compr

CONTROL SEQUENCE

The control power (115-l-60 for 60-Hz units; 230-l-50 for 50-Hz units) must be supplied directly from a separate source through a code-approved fused disconnect to the

and L2 terminals of unit power teminal block. NOTE: There is no switch or circuit breaker; only fuses. If

the control power feed is live, so is the circuit.

Crankcase heaters are wired into the control circuit. They are always operative as long as control circuit power is on even though unit may be off because of safety device action. Heaters are wired so they are on only when their respective compressors are cycled off.

A,f’tor

should be on

a prnlonged shutdoun, the

,for

hours hqfbre starting

crankcause

the unit.

heaters

When power is supplied to control circuit, unit is ready for operation providing all safety devices are satisfied, interlocks are closed and instructions on warning labels have been followed.

If schedule function is used, refer to page 11 for details

on control operation.

Off Cycle - During unit off cycle when the RUN;

STANDBY switch is in the STANDBY position, the crankcase heaters and the control system are energized. The electronic expansion valves are

also

energized. (NOTE: The control circuit power must be on at all times even when the main unit power is off.)

Start-Up - When the RUN/STANDBY switch is

moved from the STANDBY to the RUN position and there is a call for cooling, after l-l /2 to 3 minutes have passed the first compressor will start unloaded, The first circuit to start may be circuit A or B due to the automatic lead/ lag feature.

Capacity Control - (See Table 4.) The rate at which

the compressors are turned on will depend on the leaving water temperature difference from the set point, the rate of change of leaving water temperature, the return water temperature and the number of compressor stages on. The control is primarily from leaving water temperature and the other factors are used as compensation.

SEQUENCE -- On a

4 4

starts the initial compressor. The control will randomly select either circuit A or B. The liquid line solenoid valve

remains closed for 10 seconds after the initial compressor

on that refrigeration circuit starts. This permits a pump-

caiI

for cooling, the controI system

out cycle at start-up to minimize refrigerant floodback to the compressor. If the compressor in that refrigeration circuit has run in the 15 minutes before the call for

4 4 4

cooling, the pumpout cycle is bypassed.

After pumpout, the liquid line solenoid valve opens and

the electronic expansion valve starts to open.

The electronic expansion valve will open gradually to

provide a controlled start-up to prevent liquid floodback

6 6

to the compressor. Also during this period, the oil pressure switch will be bypassed for one minute.

As additional cooling is required, the control system will ramp up through the capacity steps available until the load requirement is satisfied. As capacity steps are added

compressors are brought on line, alternating between the

: E

lead and lag refrigerant circuits. As explained previously, the speed at which capacity is increased or decreased is

controlled by the temperature deviation from the set

point and the rate of change in the chilled water temperature.

Page 5

When the second or lag refrigeration circuit is started, the circuit will go through a lo-second pumpout unless the circuit has been operating in the 15 minutes prior to this start.

Upon load reduction, the control system will unload the unit in the reverse order of loading until the capacity nearly matches the load. Each time the lead compressor is cycled off, the liquid line solenoid valve and electronic expansion valve will be closed for 10 seconds prior to compressor shutdown to clear the cooler of liquid refrigerant.

Unit Shutdown - To stop unit, move the RUN/

STANDBY switch to the STANDBY position. Any refrigeration circuit that is operating at this time will

continue for 10 seconds to complete the pumpout cycle. (Lag compressors stop immediately, lead compressors

run for 10 seconds.) Complete Unit Stoppage can be caused by any of

the following conditions:

general power failure

blown fuse in control power feed disconnect

open control circuit fuse

RUN/STANDBY switch moved to STANDBY

freeze protection trip low flow protection trip

open contacts in chilled water flow switch (optional)

open contacts in any auxiliary interlock. (Terminals TBI-13 and TBJ-14, jumpered from factory, are in series with the control switch. Opening the circuit between these terminals places the unit in STANDBY mode, just as moving the control switch to STANDBY would. Code26 will appear as the operating mode in the status function display. The unit cannot start if these contacts are open, and if they open while unit is running, it will pump down and stop.

Single Circuit Stoppage can be caused by the

following: a. open contacts in

lead compressor discharge gas

thermostat b. open contacts in loss of charge switch c. open contacts in oil safety switch d. open contacts in lead compressor high-pressure switch

Stoppage of one circuit by a safety device action does not affect the other circuit. Besides stopping compressor(s), all devices listed will also close liquid line solenoid valve for that circuit.

Lag Compressor Stoppage can be caused by the

following: a. open contacts in discharge gas thermostat b. open contacts in high-pressure switch

LOW WATER TEMPERATURE CUTOUT Move

RUN/ STANDBY switch to STANDBY, then back to

RUN. Restart is automatic. AUXILIARY INTERLOCK ~- Automatic restart after

condition is corrected. OPEN CONTROL CIRCUIT FUSE

“--

Replace fuse.

Unit will restart automatically.

FREEZE PROTECTION - Unit will automatically

restart when leaving water temperature is 6 degrees F

above the leaving water set point.

HIGH-PRESSURE SWITCH, LOSS OF CHARGE SWITCH, COMPRESSOR DISCHARGE TEMPERATURE SWITCH AND OIL SAFETY SWITCH

-- Move the RUN;‘STANDBY switch to STANDBY, then back to RUN. Unit will restart automatically.

CONTROLS OPERATION

Accessing Functions and Subfunctions

Table 5. Refer also to Table 2, which shows the 5 functions (identified by name) and the subfunctions(identified by number). Table 6 shows the sequence of all the elements in a subfunction.

Display Functions

SUMMARY DISPLAY ~ Whenever the keyboard has not been used for 10 minutes, the display will auto-

matically switch to an alternating summary display. This display has 4 parts, shown below, which alternate in continuous rotating sequence.

Display TUE

12:45

MODE 26

Expansion

TODAY IS TUE, TIME IS

UNIT STANDBY

12:45

1 STAGES NUMBER OF STAGES IS 1 2 ALARMS

2 ALARMS DETECTED

STATUS FUNCTION ~ The status function shows the current status of alarm (diagnostic) codes. capacity

stages, operating modes,

chilled water set point. all

measured system temperatures, superheat values, pressure switch positions and expansion valve positions. These subfunctions are defined below. Refer to Table 6 for additional information.

[r-r-j

(Alarms) Alarms are messages that one or

more faults have been detected. Each fault is assigned a code number which is reported with the alarm. (See Table 7 for code definitions.) The codes indicate failures that cause the unit to shut down, terminate an option (such as reset) or result in the use of a default value as set point.

Up to 3 alarm codes can be stored at once. To view

If stoppage occurs more than once as a result of any of the above safety devices, determine and correct the cause before attempting another restart.

Restart Procedure, after cause for stoppage is

corrected. GENERAL POWER FAILURE ~ Unit will restart

automatically when power is restored.

BLOWN FUSE IN POWER FEED DISCONNECT Replace fuse. Restart is automatic.

them in sequence, press

m m

to enter the alarm

displays and then press key to move to the individ-

ual alarm displays. Press

EXPN)

after a code has been

dis-

played and the meaning of code will scroll across the screen.

When a diagnostic (alarm) code is stored in the display and the machine automatically resets, the code will be deleted. Codes for safeties which do not automatically reset will not be deleted until the problem is corrected

and the machine is switched to STANDBY, then back to RUN.

confinued on page IO

Page 6

Table 5 - Accessing Functions and Subfunctions

OPERATION

To access a function, press the subfunction number and the function name key. The display will show the subfunction group

To move to the other elements, scroll up or down using the arrow

keys

When the last element in a subfunction has been displayed, the first

element wilt be repeated

To move to the next subfunction, it is not necessary to use the subfunction number; pressing the function name key will advance the display through all subfunctions within a function and then back to the first

To move to another function, either depress the function name key

for the desired function (display will show the first subfunction)

Access a particular subfunction by using the subfunction number and the function name key

KEYBOARD

ENTRY

DISPLAY

RESET

RSTR

RSP

DEMAND

TtME

SET

POINT

X ALARMS

STAGES

DESCRIPTION

Reset Set Points

Reset Set Point

Reset Limit

Reset Ratio

Reset Set Point

Demand Limit Set Points

Timeof Dayand Day

of Week Display

System Set Points

X Alarms Detected

Capacity Stages

Page 7

Table 6 - Keyboard Directory

STATUS

KEYBOARD ENTI DISPLAY KEYBOARD ENTRY

X ALARMS ALARM X

ALARM X ALARM X

MODE

MODE X

STAG ES X STAGE

SET POlNT

If unit is in dual set point mode the set point currently in effect is displayed. ’

TEMPS

LWT X

EWT X

SSTA X

CGTA X

SHA X

SSTB X

CGTB X

SHB X

RST X

PRESS LCSA X

OILA X

LCSB X

OILB X

ANALOG

EXVA X

EXVB X

COMMENT

Current alarm displays Alarm 1 Alarm 2 Alarm 3

Current operating mode displays

Mode 1

Capacity stages Stage number

Current operating set point

Leaving chilled water set point

Leaving water

temperature

System temperatures

Cooler leaving water

temp

Cooler entering water

temp

Saturated suction temp

circuit A

Compressor suction gas temperature circuit A

Superheat temp circuit A

Saturated suction temp circuit B

Compressor suction gas temperature circuit B

Superheat temp circuit B

Reset temperature

Systems pressures Circuit A loss of charge

switch Circuit A oil pressure

switch Circuit B loss of charge

switch

Circuit B oil pressure

switch

System analog values

Circuit A EXV valve position

Circuit B EXV valve position

ill

During test of compressors, each compressor will start and run for 10 seconds. Compressor servicevalves and the liquid line valve must be open. Energize compressor crankcase heaters for 24 hours prior to performing compressor tests.

p-Jm

QUICK TEST

DISPLAY COMMENT

INPUTS

LWT X

EWT X

SSTA X

CGTA X

SSTB X

CGTB X

RST X LCSA X

LCSB X

OILA X

OILB X

OUTPUTS

SLDA X

SLDB X

UNLA X

UNLB X EXVAO X

EXVAC X EXVBO X EXVBC X

COMP

CA1 X

CA2 X

CBI X

CB2 X

END TEST

Factory/field test of

inputs Leaving water

temperature

Entering water

temperature Saturated suction temp

circuit A Compressor suction

gas temp circuit A Saturated suction temp

circuit B Compressor suction

gas temp circuit B Reset temperature Loss of charge switch

circuit A

Loss of charge switch circuit B

Oil pressure switch circuit A

Oil pressure switch Circuit B

Factory/field test of

outputs

Circuit A liquid line

solenoid test

Circuit B liquid line

solenoid test

Unloader A test

Unloader B test

Circurt A EXV open test

Circuit AEXVclosetest

Circuit B EXV open test

Circuit B EXV close test

Factory/field test of compressors

Circuit A compressor 1 test

Circuit A compressor 2 test

Circuit B compressor 1 test

Circuit B compressor 2

test

Leave quick test

Page 8

SERVICE CONFIGURATtONS

KEYBOARD ENTRY 1 DtSPLAY

Table 6 - Keyboard Directory (cant)

COMMENT

KEYBOARD ENTRY

DISPLAY

COMMENT

-0GGED ON \

-0G OFF KXIT

LOG /

tiERSION

xxx

FACT CFG COMP X

FFD CFG

UNLS X

RSTP X

LDSH X

FLD X

PLDN X

3ut

follows.

Shows that confrgura-

tlons

avaIlable

Conflgurations now

again password

protected

Software version number

Software version Language

Factory configuration

Number of unloaders (enter number, or. for

zero)

Field configuration ( = entry codes

Number of unloaders (enter number)

Reset type (. = none

1 = return water,

2 = space or outside air)

Load shed enable

= disable, 1 = enable)

Ftuid type 1 = brine)

Pulldown enable (.

= disable, 1 = enable)

optJon

(.=

water,

)

’

OVRD X

SCHTYP X

PERIOD 1

MON X

TUE X WED X

THU X

FRI

SAT x

SUN X

Entering number of

hours to extend

Schedule Type

( ) = entry codes

= inactive, 1 = single

set point, 2 = dual set

point)

Define time schedule period 1

Start of occupied time Return to unoccupied

time Monday flag

( ) = entry codes

(1 = yes, . = no)

Sunday flag

Time periods 2-8 (same elements as

period I)

KEYBOARD ENTRY

SET POINT

COMMENTDISPLAY

SET POINT

cwso x

cwsu x

MSP X

RESET

RSP X RSTL X RSTR X

DEMAND

DLl X

DL2 X

TIME

DAY 00.00 Current setting

System set points

Occupied chilled water set point

Unoccupied chilled

water set point appears

only when unit is in dual set point mode

Modified chilled water set point (read only). Set point determined

by reset function

Reset set points Reset set point Reset limit Reset ratio

Demand limit set points

Demand limit set point

Demand limit set point 2

Page 9

Display

Description

Table 7 - Display Codes

OPERATING MODES

ALARMS

Action

Taken

Control

Reset

Method

Probable Cause

Comp Al Al

Camp

Comp Bl Comp

Loss of charge circuit A Loss of charge circuit B

Low cooler flow Low oil pressure circuit A

low oil pressure circuit B

Freeze protection

High suction superheat circuit A High suction superheat circuit B

Low suction suoerheat circuit A

Low suction superheat circuit B Leaving water thermistor failure

Entering water thermistor failure Cooler thermistor failure circuit A Cooler thermostor failure circuit B Comp thermistor failure circuit A Comp thermistor failure circuit B

Reset thermistor failure

NOTES:

1. Freeze protection trips at 35 F (1.7 C) for water and 6 degrees F (3.3 degrees C) below set point for brine units. Resets at 6 degrees above set point.

2. All auto. reset failures that cause the unit to stop will restart the corrected.

3. All manual reset errors must be reset by moving the control switch to STANDBY then to RUN.

4. Valid resistance range for thermistors is 363,000 ohms to 216 ohms.

ii:

Failure Failure Failure

B2 Failure

Circuit A shut off Comp shut off Circuit B shut off Comp shut off

Circuit A shut off

Circuit B shut off Unit shut off Circuit A shut off

Circuit B shut off Circuit A shut off

Circuit 6 shut off Unit shut off

Use default value Circuit A shut off Circuit B shut off Circuit A shut off Circuit B shut off Stop reset

Manual Manual Manual Manual

Manual Manual

manual

Auto.

Manual Manual

Auto. Auto. Auto. Auto. Auto. Auto. Auto.

unit

when the error has been

High pressure switch trip or high discharge gas temp switch trip, on when it is not supposed to be on. Wiring error between electronic control and compressor relay.

Low refrigerant charge, or loss of charge pressure switch failure.

No cooler flow or reverse cooler flow Oil pump failure or low oil level, or switch failure.

Low cooler flow

Low charge or EXV failure, or plugged filter drier.

EXV failure ar cooler thermistor error.

Thermistor failure, or wiring error, or thermistor not connected to input terminals.

Page 10

p-JB

(Modes) The operating mode codes are dis-

(Position) The position subfunction displays

played to indicate the operating status of the unit at a

given time. (See Table 7).

The modes are explained in the Troubleshooting sec-

tion on page 12.

[3-i

ity stage number, from 1 to 8. See Table 4 for compressor loading sequence to enter the STAGES subfunction,

depress stage number.

leaving water temperature and the Leaving chilled water set point. If the unit is programmed for dual set point, the chilled water set point currently in effect (either occupied or unoccupied) will be displayed. If reset is in effect, the unit will be operating to the modified chilled

water set point. This means that the leaving water temperature may not equal the chilled water set point. The modified the status function. To read the modified chilled water set point, refer to the Set Point Function section, page 1

To enter the set point subfunction, depress then use the water set point followed by the leaving water temperature.

EKI

displays the readings at temperature sensing thermistors. To read a temperature, enter then scroll to

the desired temperature using the order of the readouts.

(Stages) This subfunction displays the capac-

m F]

chrlled

STAT

(Temperature) The temperature subfunction

and use the

(Set Point) This subfunction displays the

water set point will not be displayed in

key to display the leaving chilled

III

key to display the

key. Table 6 shows

pqz-],

the current position of the electronic expansion in steps:

Fully Open (760)

Operating Position ( 160 Minimum)

Fully Closed, Circuit Shut Down (0)

TEST FLJNCTlOh’ - The test operates the Quick Test

diagnostic program.

mode, the test subfunctions will energize the solenoid valves, unloaders, electronic expansion valves and compressors. The solenoids and unloaders will energize for 3 minutes. The expansion valve will travel to fully open in one test and to fully closed in the next. The compressors will energize for 10 seconds. The subfunctions are ex-

plained below. Refer to Table6 for all the elements in the subfunctions.

p-j

i;;;;i ~-

1-q m -

except for compressors.

[-Y-j

T;;;;i

k1 I:ESTI ~

NOTE: The Quick Test energizes the alarm light and alarm relay. They will remain energized as long as the unit is in Quick Test.

To reach a particular test, enter its subfunction number and then scroll to the desired test with the test can be terminated by pressing after a test has started will advance the system to the next

test, whether the current one is operating or has timed out. Once in the next step, you may start the test by

pressing While the unit is in Quick Test, you may access another

display or function by depressing the appropriate keys; however, the unit will remain in the Quick Test function

until

for 10 minutes, the unit will automatically leave the

Quick Test function.

Tests the compressors.

ENTR

TEST

q cl

When the unit is in STANDBY

Displays the status of all inputs.

Tests the outputs from the processor,

Takes the unit out of Quick Test.

) . Pressing

or advance past it by pressing h .

is entered, or, if the keyboard is not used

valves

key. A

17-l

status of the oil pressure and loss of charge switches. The display will show LOW or KRM for the oil pressure switch and LOW or SAFE for loss of charge switch.

(Pressure) This subfunction displays the

Page 11

Programming Functions

SERVICE FUNCTION - The service function allows the operator to verify factory configurations and read or change field configurations. The service subfunctions are listed below. (See Table 6 for details.)

The operator must use this subfunction to

log on before performing to log off after completing

pJ@-

language option.

(number of compressors).

pq m .-..

for number of unloaders and reset type and to enable the

machine for load shed, pulldown, or brine operation.

NOTE: Thenf

Used to verify software version and

Used to verify factory configurations

Usrd to read or change field configuration

key is used to enable or turn on certain

any other subfunction,

service subfunctions.

and

If single in the schedule function, the display

set point.

c. The modified chilled water set point is determined by

the microprocessor as a result of the reset function, and is displayed for reference only; it cannot be set or changed by the operator. If reset is not in effect, the modified set point will be the same as either the occupied or unoccupied chilled water set point, according to how the schedule function has been programmed.

ratio

reset

funct

set point or inactive

show the

will

Displays the reset, reset Limits, and reset

set points, These set points are not accessible when

type has been configured for NONE in the service

ion.

SET

Displays the demand limit set points.

--Displays time of day and day of week.

sched ule has been

when + is depressed

then

modified chilled water

selected

functions; the

SET POINT FUNCTION -- Set points are entered through the keyboard. Set points can be changed within the upper and lower limits, which are fixed. The ranges are listed below.

Chilled

Water Set Point

Water:

to 70 F (4.4 to 21 C)

Brine (Special Order Units):

to 70 F (-9.4 to 21 C)

Rc~set

Set Point

0 to

95 F (-17.8 to 35 C)

Reset Limit

0to80 F (-17.8 to 26.7 C)

Reset Ratio

0 to 100%

Ilemand Limit Set

Step I Capacity Reduction:

0% to

Step 2 Capacity Reduction:

0% to

Set points aregrouped in subfunctions as follows:

The first

set point.

b. The next value to

schedule function h

If dual set point-has been selected, the next set point

after

L-J

chilled water set point; this will be followed by the

modified chilled water set point.

key is used to disablethesefunctions.

key is pressed the display will show 00.00.

Poiot5

100%

Displays chilled water set points.

value shown is the occupied chilled water

displayed depends on

.as

been programmed. (See

has been pressed will be the unoccupied

how the

below.)

SCHEDULE FUNCTION ~ This function provides a

means to automaticafly switch the chiller from an occupied mode to an unoccupied mode. When using the schedule function, the chilled water pump relay, located in the unit control box, must be used to switch the chilled water pump on and off. The chilled water pump relay will start the chilled water pump but the compressors will not run until the remote chilled water pump interlock contacts are closed and the leaving chilled water temperature is above set point. If a remote chilled water pump interlock is not used. the first compressor will start (upon a

call

for cooling) approximately one minute after the

chilled water pump is turned on.

The schedule

ngle

set point. or

When the schedule is configured for inactive, the

chilled water pump relay remains energized continuously

but is not used since the chiller is usually controlled by

remote chilled water pump interlock contacts.

When the schedule is set for single set point operation,

the

chilled

the chiller is in the occupied mode regardless of whether the chiller is running. When the chiller is in unoccupied mode, the chilled water pump relay will not be energized.

When the schedule is set for dual set point, the chilled

water pump relay will be energized continuously, in both

occupied and unoccupied modes. The occupied mode places the occupied chilled water set point into effect; the unoccupied mode places the unoccupied chiller water set point into effect.

The schedule consists of from one to 8 occupied time

periods, set by the operator. These time periods can be

flagged to be in effect or not in effect on each day of the week. The day begins at 00.00 and ends at 24.00. The

machine will be in unoccupied mode unless a scheduled

time period is in effect. If an occupied period is to extend

past midnight, it must be programmed in the following manner: Occupied period must end at 24:00 hours

(midnight); a new occupied period must be programmed to begin at

The time schedule can be overridden to keep the unit in the occupied mode for one, 2, 3 or 4 hours on a onetime basis.

function can be programmed

dual

set

pntnt

operation.

water pump relay will be energized whenever

0O:OO

hours.

for

inactive,

Page 12

TROUBLESHOOTING

If necessary, review the Flotronic Plus Control System, Control Sequence, and Controls Operation sections found in this book. Tables 5 and 6 show how to use the keyboard/display module to access functions and subfunctions. (These procedures are also explained in the

3OHR,HS Installation, Start-Upand Service Instructions

along with examples and details on using the control features. A copy of the installation instructions should be kept handy while troubleshooting.)

Checking Display Codes - To determine how the

machine has been programmed to operate, check the

diagnostic information ( and operating

If the schedule is holding the machine off when it is needed, set the schedule for inactive mode until the schedule can be properly reprogrammed. (See the Schedule Function section of the Installation, Start-Up and Service Instructions.) The override feature can also

-be

used to temporarily place the unit in occupied mode. Enter (1 to 4), then press

then the number of hours to override

SCHD

EWR

.0If the unit is in override and

you wish to cancel it, enter zero hours in the same manner. Run Mode (28)

To enter the MODES subfunction, depress

and use the

key to determine if more than one

p-j Fj

mode displays

(

If no display appears,

follow the procedures in Troubleshooting, Modules, page 23. If the display is working, continue as follows:

1. Note all the alarm codes displayed

(

2. Note all the operating mode codes displayed

(ppq).

3. Note the leaving chilled water temperature set point in effect and the current leaving water temperature

If the machine is running, compare the “in effect” leaving water temperature set point with the current water temperature. Remember that if reset is in effect, they may be different because the machine is operating to the modified chilled water set point. If the current temperature is equal to the set point but the set point is not the one desired, recall that if dual set point has been selected in the schedule function, there are 2 set points to which the machine can be operating. Check

the programming of the schedule function to see if the

occupied or unoccupied set point should be in effect.

OPERATING MODE CODES - Following is an explanation of the operating mode codes:

Temperature Reset (21) ~ In this mode, the unit is using

temperature reset to adjust the set point, and the unit is controlling to the modified set point. This means that the leaving water temperature may not equal the chilled water set point. The set point can be modified based on return water, outside air temperature or space temperature.

Demand Limit (22) - This indicates that the capacity of

the unit is being limited by the demand limit control

option. The unit may not be able to produce the desired leaving water temperature because the unit may not load to full capacity.

Pulldown Control (24) -- If this option is in effect and

the cooler water temperature is warm, extra stages will not be added if the water temperature leaving the cooler is decreasing faster than I0 F (0.6 C) per minute.

Standby (26) ~ The unit is being held in the standby mode either because the RUN /STANDBY switch is

onen

or a set of relay contacts in series with the KUN/ STANDBY switch is open (contacts wired between terminals TBl-13 and TBI-14).

Unoccupied Mode (27) - In dual set point schedule, this mode means the machine is operating to the unoccupied set point. In single set point schedule, this mode shuts down the unit in the same manner as “Unit Standby.”

mode applies.

Do not attempt to bypass, short or modify the control circuit or electronic boards in any way to correct a problem. This could result in component failures or a hazardous operating condition.

ALARM CODES - The following is a detailed description of each alarm code error and the possible cause.

Manual reset of an alarm is accomplished by moving the RUN/STANDBY switch to STANDBY, then back

to RUN. Codes 5 l-54, Compressor Failure - If the DSIO relay

module relay or control relay feedback switch opens

during operation of a compressor, the microprocessor

will detect this and will stop the compressor, energize the alarm light, and display a code of 5 1 to 54, depending on the compressor. The compressor will be locked off; to reset, use the manual reset method.

If the lead compressor in a circuit is shut down, all the

other compressors in the circuit will be stopped and locked off. Only the alarm code for the lead compressor will be displayed,

The microprocessor has also been programmed to indicate a compressor failure if the feedback terminal on the 253 terminal strip receives voltage when the com-

pressor is not supposed to be on. Following are possible causes for this failure:

High-Pressure Switch Open - The high-pressure switch

for each compressor is wired in series with the 24-volt power that energizes the compressor control relay. If the high-pressure switch opens during operation the com-

pressor will stop and this will be detected by the micro-

processor through the feedback terminals.

Discharge

Gas Thermostat ~ The discharge gas thermo-

stat switch in each compressor is also wired in series with the 24-volt power that energizes the control relay (CR).

If the switch opens during operation of the compressor, the compressor will be stopped and the failure will be detected through the feedback terminals.

DSIO Module Failure ~ If a DSIO relay module relay

fails open or closed, the microprocessor will detect this and lock the compressor off and indicate an error.

Wiring Errors - If a wiring error exists causing the CR

or feedback switch not to function properly, the micro-

nrocessor

Processor

will indicate an error.

(PSIO)

Failure -

If the hardware that monitors the feedback switch fails or the processor fails to energize the relay module relay to ON, an error may be indicated.

: I

t.,

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 S3 is

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 1 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 the feedback input (terminal t

Failure of power to terminal t

255 1 I and I2 should be

closed

c<)ntroX

relay (CR 1) and

~I”I 2,13).

OLI

2J3 when contacts

wilt

cause

a code 5 1 alarm.

Terminal 2 on 293 is the other leg of 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 processor module fails in a manner that the switch cannot be read properly, an error may be indicated.

Code 61, No Cooler

Flow

The microprocessor contains 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

wiring

Errur -

not

running.

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 superheat failure.

EXY Failure - If the EXV fails to open enough to feed

the proper amount of refrigerant, the error will occur.

EXV

Dviveu

hardware that controls the EXVs fails, the

Moduk Failure ~ Xf the DSIO module

valve

will

not move.

Page 14

COOLER TUBE

LEAVING WATER

THERMISTOR..

Fig. 4 - Cooler Sensor Locations

SUCTION

,----CONNECTION

INLET

CONNECTION

ENTERING COOLER

WATER SENSOR

(T21

(T58T6)

Bau’

The~~isfor ~ Thermistors mis-located or out of

calibration. Code 68 and 69, Low Suction Superheat

~‘--

if the following logic is satisfied, then all the compressors on the circuit will be stopped.

Suction superheat is equal to 0°F

(OOC)

or the saturated suction is greater than 58 F (14.4 C) and either condition has been true for more than 5 minutes.

Possible causes for this failure are a stuck electronic expansion valve or thermistors mis-located or out of calibration.

To reset, use the manual reset method.

Code 71 to 81, Thermistor Failure

~~~

If the measured

temperature of a thermistor is less than -60 F (-51 C)

(363,000 ohms) or greater than 240 F (116 C) (2 16 ohms),

the appropriate sensor error code will be displayed and the unit will be stopped. The thermistor failures will

automatically reset. The following is a summary of

possible causes.

Thermistor Failure - A shorted or open circuit ther-

mistor will cause the failure.

Wiving Failure - A shorted or open circuit will cause

the failure.

P~oc~essnr

Module

Fczilure ~

If the circuitry in the pro-

cessor module fails, the error could occur.

NOTE: The reset thermistor is an optional thermistor

and is only used with outside or space temperature reset.

It will only be read by the processor if the unit is con-

figured for outside or space temperature reset.

The absence of a thermistor failure does not necessarily mean that a thermistor is accurate. To determine accuracy, the reading must be compared with a measure-

ment of the actual temperature to which the thermistor

probe is exposed.

Quick Test - The Quick Test feature allows the service

technician to individually test all the inputs and outputs of the control system.

The test function operates the Quick Test diagnostic program. When the unit is in STANDBY mode, the test subfunctions will energize the solenoid valves, unloaders, electronic expansion valves and compressors. The solenoids and unloaders will energize for 3 minutes. The electronic expansion valve will travel to fully open in one test and to fully closed in the next. The compressors will energize for 10 seconds. The subfunctions are explained below. Refer to Table 6 for all the elements in the subfunctions.

NOTE: The Quick Test energizes the alarm light and alarm relay. They will remain energized as long as the unit is in Quick Test.

To reach a particular test, enter its subfunction number and then scroll to the desired test with the0+ test can be terminated by pressing

. Pressing

key. A

after a test has started will advance the system to the next test, whether the current one is operating or has timed out. Once in the next step, you may start the test

by pressing

ENm

or advance past it by pressing h .

cl cl

While the unit is in Quick Test, you may access another

display or function by depressing the appropriate keys;

however, the unit will remain in the Quick Test function until

T;;i

is entered, or, if the keyboard is

not used for 10 minutes, the unit will automatically leave the Quick Test function. See the following example:

Page 15

y$.

KEYBOARD

ENTRY RESPONSE

TEST

COMP

DISPLAY

q u

CAM

OFF

ENTR

CA1 ON

CAM

OFF

CA2 OFF

END TEST

COMMENTS

Factory field test of compressors

subfunction of test function

Circuit A, compressor 1 test

Pressing ENTR starts the test; when the compressor should be running the display shows CA1 on

If the test is allowed to time out, the display will show

Pressing the down arrow key advances the system to circuit A, compressor 2 test

If no other test is desired, exit quick test

CA1

off

Loss of charge and oil pressure switch tests show LOW if the switch is closed. The input channel can be tested by disconnecting the switch and using a jumper to simulate a closed or open circuit. (See Fig. 5.)

Note that the switch is read by the processor period-

ically, not continuously. When the switch position is

changed, it may take a few seconds before the display

changes.

The [q

outputs except for the compressor control outputs. (See

Fig. 6.)

The liquid line solenoid and unloader solenoid tests

will energize the output when

open

and NRM or SAFE if the switch is

subfunction will energize the control

ENTR

is pressed. It will

Refer to Fig.

module in a panel is numbered ( I,

strip is labeled (52, 53, J4...). The terminal strip on the

machine schematic combines the module and strip

numbers. module 2. The module numbers can be found on the com-

ponent arrangement label.

The

switch inputs. The thermistor tests display the temperature that the thermistor is reading. If the display and the actual temperature do not match, the thermistor and the input channel can each be checked.

To check the thermistor, disconnect its leads from the

PSI0

terminal (the entire connector can be pulled from

the

PSI0

resistance of the thermistor, then find the corresponding temperature in Table 8.

This temperature should match the actual temperature

to which the thermistor is exposed.

The thermistor can be checked while connected to the

processor by measuring the voltage across its terminals and finding the corresponding temperature in Table 8. This method can only be used if it is certain that the processor circuits are putting out the correct voltage. If there is any doubt, the thermistor should be checked by

the resistance method.

The input channel can be tested by removing the

thermistor from the terminals and attaching a fixed resistor with a value between 40,000 ohms and 400 ohms. Refer to Table 8 and find the temperature that corresponds to that resistance; this temperature should

appear in the Quick Test display.

5,6

and 7 for specific control wiring. Each

For example, 2JJ is terminal strip 53 on

(;;;;I subfunction checks the thermistor and

by pulling the connector to the left). Read the

2,3,4...).

Each terminal

remain energized until either the

10 minutes have elapsed. When the processor energizes the output reiay it will display the word ON on the right side of the display.

The EXV open and close tests drive the EXV fully open

or fully closed. See The EXV Checkout Procedure for

more information. The display will read either zero steps

open or 760 steps open.

The 14 I;;;;]

control relays for 10 seconds and displays the compressor

status feedback.

The liquid line solenoid in the same circuit will energize for 10 seconds and the EXV will open 180 steps, then close.

When control power reaches the compressor control

relay it also reaches the feedback terminal on terminal

strip 233 (see Fig. 7). When this occurs the display will

switch from OFF to UN. If the display changes but the

compressor does not start, check the control relay,

tactor, compressor circuit breaker, interconnecting

wiring, and the compressor motor.

If the display does not change, check the discharge gas thermostat, high-pressure switch, condenser fan overload (on 30HS, if used), continuity across the DSIO terminals and interconnecting wiring.

To protect the compressors from repeated cycling, a delay of one minute is required before the same compressor is retested.

The 4 Quick Test mode. Press

show EKD TEST; press then shows END TEST again.

subfunction energizes the compressor

TEST

subfunctions take the unit out of the

14 H

ENS

J key is pressed or

con-

and the display will

and the display blinks and

Page 16

THE PROCESSOR OPERATES THESE CONTACTS

LC%%R&F

CIRCUIT

LOSS OF CHARGE

CiRCUtT

24v

FEED

1 /

Fig. 5 - Compressor 24-V Control Circuit Wiring

(Simplified)

24v

DSlO

TERM ?$I.- STRIP

NEUTRAL

UNLOADER CKT. A

UNLOADER CKT.

LIQUID

LINE

SOLENOID CKT. A

LIQUID

LINE

SOLENOID CKT.

24V FEED 24V NEUTRAL

Fig. 6 - Pressure Feedback Circuit Wiring

(Simplified)

Fig. 7 - Auxiliary Components 24-V Control

Circuit Wiring (Simplified)

Page 17

Table 8a - Thermistsr Temperature

Resistance and Voltage (English)

TEMPERATURE

-25.0

-24.0

-23.0

-22.0

-21.0

-20.0

-19.0

-18.0

-17.0

-16.0

-15.0

-14.0

-13.0

-12.0

-11.0

-10.0

-9.0

-8.0

-7.0

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

15.0

16.0

17.0

18.0

19.0

20.0

21.0

22.0

23.0

24.0

25.0

26.0

27.0

28.0

29.0

30.0

31.0

32.0

33.0

34.0

35.0

36.0

37.0

38.0

39.0

40.0

41.0

42.0

43.0

44.0

45.0

46.0

47.0

48.0

49.0

50.0

51.0

52.0

53.0

54.0

55.0

56.0

57.0

VOLTAGE

DROP

(Y)

4.821

4.818

4.814

4.806

4.800

4.793

4.786

4.779

4.772

4.764

4.757

4.749

4.740

4.734

4.724

4.715

4.705

4.696

4.688

4.676

4.666

4.657

4.648

4.636

4.624

4.613

4.602

4.592

4.579

4.567

4.554

4.540

4.527

4.514

4.501

4.487

4.472

4.457

4.442

4.427

4.413

4.397

4.381

4.366

4.348

4.330

4.313

4.295

4.278

4.258

4.241

4.223

4.202

4.184

4.165

4.145

4.125

4.103

4.082

4.059

4.037

4.017

3.994

3.968

3.948

3.927

3.902

3.878

3.854

3.828

3.805

3.781

3.757

3.729

3.705

3.679

3.653

3.627

3.600

3.575

3.547

3.520

3.493

RESISTANCE

(OHIWS)

98009,6

94707.1

9152'8,5

88448.9

85485.5

82627.2

79870.6

77212.0

74647.9

72175.1

69790.3

67490.4

6,5272.4

63133.3

61070.3

59080.6

57161.7

55310.9

53525.8

51804.0

50143.2

48541.1

46995.6

45504.7

44066.3

42678.5

41339.3

40047.1

38800.0

37596.4

36434.7

35313.3

34230.7

33185.4

32176.2

31201.5

30260.1

29350.9

28472.5

27623.8

26803.7

26011.2

25245.1

24504.6

23788.7

23096.4

22426.9

21779.3

21152.8

20546.7

19960.2

19392.5

18843.0

18311.0

17795.8

17297.0

16813.8

16345.7

15892.2

15452.7

15026.7

14613.9

14213.6

13825.5

13449.2

13084.2

12730.1

12386.6 120533

11730.0

11416.l

11111.5

10815.8

10528.7

10250.0

9979.3

9716.5

9461.3

9213.4

8972.6

8738.6

8511.4

8290.6

rEMPERATURE

(Ff

58.0

59.0

661.0

61.0 620

63.0

644.0

65.0

66.0

67.0

68.0

69.0

70.0

71.0 T2.0

73.13

74.0

75.0

76.0

77.0

76.0

79.0

80.0

87.0

82.0

83.0

84.0

85.0

E6.0

87.0

88,O

89.0

90.0

91.0

92.0

93.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

105.0

106.0

107.0

108.0

109.0

110.0

111.0

112.0

113.0

114.0

115.0

116.0

117.0

118.0

119.0

120.0

121.0

122.0

123.0

124.0

125.0

126.0

127.0

128.0

129.0

130.0

131.0

132.0

133.0

134.0

135.0

136.0

137.0

138.0

139.0

140.0

VOLTAGE

DROP(V)

3.464

3.437

3.409

3.382

3.353

3.323

3.295 3,267

3.238

3.210

3.184 3,152

3.123

3.093

3.064

3.034

3.005

2.977

2.947

2.917

2.884

2.857

2.827

2.797

2.766

2.738

2.708

2.679

2.650

2.622

2.593

2.563

2.533

2.505

2.476

2.447

2.417

2.388

2.360

2.332

2.305

2.277

2.251

2.217

2.189

2.162

2.136

2.107

2.080

2.053

2.028

2.001

1.973

1.946

1.919

1.897

1.870

1.846

1.822

1.792

1.771

1.748

1.724

1.702

1.676

1.653

1.630

1.607 I.585

1.562 I.538

1.517

1.496

1.474

1.453

1.431

1.408

1.389

1.369

1.348

1.327

1.308

1.291

RESISTANCE

(OHMS)

8076.1

7867.7

7665.1

7468.3

7277.1

7091.2 69106

6735.1

6564.4

6398.6

6237.5

6080.8

5928.6

5780.6

5636.8

5497.0

5361.2

5229.1

5100.8

4976.0

4854.8

4736.9

4622.4

4511.1

4402.9

4297.7

4195.5

4096.:

3999.6

3905.7

3814.4

3725.8

3639.5

3555.7

3474.2

3395.0

3318.0

3243.1

3170.3

3099.4

3030.5

2963.5

2898.4

2834.9

2773.2

2713.1

2654.7

2597.8

2542.3

2488.3

2435.8

2384.5

2334.6

2285.9

2238.5

2192.2

2147.0

2103.0

2060.0

2018.0

1977.0

1936.9

1897.8

1859.5

1822.1

1785.5

1749.7

1714.7

1680.4

1646.8

1613.8

1581.6

1550.0

1519.0

1488.6

1458.8

1429.6

1400.9

1372.7

1345.1

1318.0

1291.3

1265.2

Page 18

Table 8b - Thermistor Temperature vs Resistance and Voltage

(Sk)

TEMPERATURE

-39

-38

-37

-36

-35

-34

-33

-32

-31

-30

-29

-28

-27

-26

-25

-24

-23

-22

-21

-20

-19

-la

-17

-16

-15

-14

-63

-12

-17

-10

-9

-a

-7

-6

-5

-4

-3

-2

-3 0

1 2 3 4

r ;

7 a 9

14 15

VOLTAGE

4.8961

4.8892 4

4.88177

4.874

4.86577

4.85709

4.84793

4.83a39

4.82808

4.81736

4.80608

4.79421

4.78151

4.76863

4.75488

4.74046

4.72534

4.7095

4.6929

4.67557

4.65743

4.6365

4.61873

4.59811

4.57663

4.55426

4.53099

4.50678

4.48165

4.45556

4.42794

4.40044

4.37141

4.34138

4.31036

4.27829

4.24521

4.21115

4.f7605

4.73993

4.7

0279

4.06471

4.0256

3.98557

3.94454

3.90262

3.85979

3.816

3.77142

3.726

3.67969

3.63271

3.58496

3.53653

3.48742

3.43771

RESISTANCE

(KOhtTlS)

166,23

157.44

147.41

138.09

129.41

121.33

I i

3.81

106.88

100.26

94.165

88.48

83.17

78.125

73.58

69.25

65.205

61.42

57.875

54.555

51.45

48.536

45.807

43.247

40.845

38.592

36.476

34.489

32.621

30.866

29.216

27.633

26.202

24.827

23.532

22.313

21.163

20.079

19.058

a.094

17.184

16.325

15.515

14.749

14.026

13.342

12.696

12.085

11.506

10.959

10.441

9.9495

9.485

9.0445

8.627

a.237

7.8555

TEMPERATURE

(C)

16 17 la 19

22 23 24 25 26 27 28 29

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

57 52 53 54 55 56 57 58

60 61 62 63 64 65 66 67 68 69

VOLTAGE

3.38739

3.3366

3.2853

3.23369

3.18154

3.12913

3.07641

3.02348

2.97044

2,91715

2.86384

2.81049

2.75717

2.70394

2.65082

2.59787

2.54514

2.4927

2.44053

2.38871

2.33733

2.2&633

2.23582

ma579

2.7363

2.08738

203907 1,99135

1.94433

,a9792 1 .a5224 1>80726

1.76302

1.71947

1.67672

1.63474

1,59351

1.55306

1.51333

1.47449

la43642

1.39911

1.36264

1,32693 I,29199

1.25786

1.22454

1.192

I,16014

1.12916

1.09887

1.06889

1.04046

I.01238

.984975

RESfSTANCE

(KL3hll-S)

7.499

7.161

6.84

6.5358

6.246

5.971

5.7095

5.461

5.225

4.7861

4.5825

4.3887

4.2042

4.0284

3.8609

3.7013

3.5492

3.4041

3.2657

3.1338

3.0078

2.8876

2.7728

2.6632

2.5585

2.4585

2.3629

2.2716

2.1842

2.1007

2.0208

1.9444

1.8712

1.8012

1.7342

1.67

1.6085

1.5495

1.4931

7.439

1.3871

1.3374

1.2897

1.2439

1.2

1.1579

1.1175

1.0786

1.0414

1.0056

.9707 .93a1 .90635 .8758

Page 19

Electronic Expansion Valves

CHECKOUT PRCKEDCRE ~

1-<11low steps below

to diagnose and correct EXV problems, For an explanarjon of EXV operation, see

Step 1 - Check EXV Driver Outputs ~ output signals at appropriate terminals on module (Fig. 8) as

Connect positive test

Set meter for approximately 20

paye

folIows:

lcad

1. Chcuk l_XV

the E.YV

driver

to terminal 1 on EXV driver.

vdc.

Enter outputs sub-

12.

function of test function by pressing

m ‘4

advance to EXVA Open Quick Test by pressing times. Press

ENm

. The driver should drive the EXV fully

iRmIl

, then

h 5

open. During the next several seconds connect the negative test lead to pins 2. 3, 4 and 5 in succession. Voltage should rise and fall at each pin. If it remains constant at a voltage or at zero volts, remove the connector to the valve

and recheck. Press to reach the EXV A

Test. If a problem still exists, replace the EXV

driv’er.

Quick

If the voltage reading is correct, the expansion valve should be checked. Next, text EXVB. Connect the positive test lead to pin 7 and the negative to pin

8,9, IO,

1 l in succes-

sion during the EXVB Quick Test.

Step 2

Check EXV Wiring

Check wiring to elec-

tronic expansion valves from terminal strip on EXV driver (Fig.

Check color coding and wire connections. Make sure

8).

they are connected to correct terminals at driver and

EXV plug

connections.

EXV A

Fig. 8 - EXV Cable Connections to

EXV Driver Module

2. Check for continuity and tight connection at all pin

terminals.

Check plug connections at driver and at EXVs. He sure

EXV connections are not crossed.

Step 3 ~ Check Resistance of EXV Motor Windings Remove between

rnBug

c’ommon

137

terminal strip and check resistance

lead (red wire, terminal

and remain-

ing leads A, B, C. and E (see Fig. 8). Resistance should be 25 ohms

-t-i’

-2 ohms.

Page 20

-MUFFLERS MUFFLERS

COMPRESSORS COMPRESSORS

Fig. 9 - Thermistor Locations

Step 4

Check thermistors that control processor output voltage pulses to EXVs. Circuit A thermistors are T5 and T7. Circuit B thermistors are T6 and T8. Refer to Fig. 9 for location.

2. Check thermistor calibration at known temperature

3. Make sure that thermistor leads are connected to

operation of EXV can be checked by using procedures

outlined in Step 5.

Step 5 ~ Check Operation of the EXV ~ Use following

procedure to check actual operation ofelectronic expansion valves.

NOTE: Be sure to allow compressors to run full

seconds at each step.

2. Turn OFF compressor circuit breaker(s). Close com-

Check Thermistors That Control EXV

lJse

the temperature subfunction of the status function

(pp=])

correctly.

by measuring actual resistance and comparing value measured with

proper pin terminals at 157 terminal strip on processor module and that thermistor probes are located in proper position in refrigerant circuit (Fig. 9).

When above checks have been completed, actual

Close liquid line service valve for circut to be checked

and run through the Quick Test step (in subfunction 3 of test function) for the lead compressor in that circuit to pump down the

Repeat test step 3 times to ensure that all refrigerant

has been pumped from low side.

pressor service valves and vent any remaining refrigerant from low side of system.

to determine if thermistors are reading

values

listed in Table 8.

low

side of the system.

3. Remove screws holding top cover of EXV. Carefully remove top cover, using caution to avoid damage to the motor leads. If EXV plug was disconnected during this process, reconnect it after the cover is removed.

4. Enter appropriate EXV Quick Test step for EVXA or EXVB in the outputs subfunction of the test function

Press

ENTR

(p-p-j,.

lifted off the EXV valve body, observe operation of valve motor and lead screw. The motor should turn in the clockwise direction and the lead screw should move down into the motor hub until the valve is fully closed or fully open depending on whether you initiate the open or close test step for that valve. Lead screw movement should be smooth and uniform from fully open to fully closed position, or from fully closed to

fully open.

If valve is properly connected to processor and receiv-

ing correct signals, yet does not operate as described

above, the valve

The operation of the EXV valve can also be checked

without removing the top cover. This method depends on the operator’s skill in determining whether or not the valve is moving, To use this method, initiate the Quick Test to open the valve. Immediately grasp the EXV valve

body with the hand. As the valve drives open, a soft, smooth pulse will be felt for approximately 26 seconds as the valve travels from fully closed to fully open. When the valve reaches the end of its opening stroke, a hard pulse will be felt momentarily. Drive the valve closed and a soft, smooth pulse will be felt for the 26 seconds necessary for the valve to travel from fully open to fully closed. When the valve reaches the end of its stroke, a hard pulse will again be valve should be driven through at least 2 complete cycles to be sure it is operating properly. If a hard pulse is felt for the 26 second duration, the valve is not moving and should be replaced.

shouId

feelt

as the valve overdrives by 50 steps. The

to initiate test. With cover

be replaced.

,:’ ‘:

Page 21

The EXV test can be repeated

r-rs

required by pressing

may be due to out-of-calibration thcrmistorfs), or intermittent connections between processor board tcrn?inals

and EXV plug. Recheck all wiring connections

;tnd

voltage signals.

Other possible causes of improper refrigerant flow control could be restrictions in liquid line. Check plugged filter drier(s), stuck liquid line solenoid

i‘or

valve(s)

or restricted metering slots in the EXV. Formation of ice or frost on lower body of electronic expansion valve is one symptom of restricted metering slots. Clean or replace valve if necessary.

NOTE: Frosting of valve is normal during compressor Quick Test steps and at initial start-up. Frost should dissipate after 5 to 10 minutes operation of a system that is operating properly. If valve is to be replaced, wrap valve with a wet cloth to prevent excessive heat from damaging internal components.

EXV OPERATION - These valves control the flow of

liquid refrigerant into the cooler. They are operated by

the

processor

to maintain 20 degrees F of superheat

between the cooler entering refrigerant thermistor and the

lead compressor entering gas thermistor (located between the compressor motor and the cylinders). There is one

EXV per circuit. A cutaway drawing of valve is shown

in Fig.

IO.

phase condition (liquid and vapor). To control refrlg-

erant flow for different operating conditions, piston

moves up and down over orifice, thereby changing orifice size. Piston is moved by a linear stepper motor. Stepper motor moves in increments and is controlled directly by

processor module. As stepper motor rotates, motion is

transferred into linear movement by lead screw. Through stepper

st~‘cdkt’ r*csults

module, it is possible to track initial start-up, EXV is fully position is tracked by processor by constantly

motor and

n~otjc‘rn

arc obtained. The large number of steps and long

lead

screws, 760 discrete steps of

in very itccurate control of refrigerant flow.

Because

tht:

EXVs

art:

wntmEItd hy rtw

vaIvc pr>sition.

cloxcd. After

processor

During

start-up,

thsct-ving

v;rIkc

amount of valve movement.

The processor keeps track of the EXV position by counting the number of open and closed to each valve. II has no direct

phvsical

steps

it has

sent

feedback of valve position. Whenever the unit is switched from STANDBY to

RUIN,

processor will send enough closing pulses to the

both valves will be initialized. This

means

\,alve

the

to move it from fully open to fully closed and then reset the position counter to zero.

The EXV open Quick Tests will send enough pulses to the valve to drive it from fully closed to fully open. The position of the on the number of

valve

at the start of the test has no effect

puI$cs

sent.

In the same manner, the EXV close Quick Tests will send

enough pulses tr, rhe

valve to drive it from fully

open to fully closed,

When the EXV opens, the metering slots are not uncovered until step when

the

760

circuit is operating. The fully open position is

steps.

160.

This is fully closed position

4 -STEPPER MOTOR 3 -LEAD SCREW

2 -PISTON

1 -ORIFICE ASSEMBLY

Fig. 10 - Electronic Expansion Valve

High-pressure liquid refrigerant enters valve through

bottom. A series of calibrated

slots

have been machined in side of orifice assembly. As refrigerant passes through orifice, pressure drops and refrigerant changes to a 2-

The m r]STAT

positions. They should operates. If a

subfunction shows the EXV valve

ch,ange

constantly while the unit

vrxlve

should stop moving for any reason (mechanical or electrical) other than a processor or thermistor failure. the processor will continue to attempt to open the calculated valve position reaches

<)r

close the valve to correct the superheat. Once

160

(fully closed) or 760 (fully open) it will remain there. If the EXV position reading remains at 160 or 760 and the cooler and compressor refrigerant thermistor displays are reading the measured temperature correctly, the EXV is not moving. Follow the EXV checkout procedure to determine the cause.

The EXV is also used to limit cooler suction tem-

perature to 55 F (13 C). This makes it possible for the

chiller to start at higher cooler water temperatures without overloading compressor. This is commonly referred

to as MOP (maximum operating pressure).

Page 22

Thermistors

All thermistors are identical in their

temperature vs resistance performance. Resistance at

various temperatures are listed in Table 8.

SENSOR REPLACEMENT -

(Compressor and Cooler)

TI,

T2, T5, T6, T7,

LOCATION -- General location of thermistor sensors are shown in Fig. 9.

Cooler Leaving Water Sensor, TL, is located in the leaving water nozzle. The probe is immersed directly in the water. All thermistor connections are made through a

1,/4-in.

coupling (Fig. I I). Actual location is shown in

Fig. 4. Cooler Entering Water Sensor, T2, is located in the cooler

shell in first baffle space, near to tube bundle. Actual location is shown in Fig. 4.

Cooler Saturated Suction Temperature Sensors, T5 and

T6, are located next to refrigerant inlet in cooler head.

Thermistors are immersed directly into refrigerant.

Typical location is shown in Fig. 4. Compressor Suction Gas Temperature Sensors, T7 and

T8, are located in lead compressor in each circuit in a

suction passage between motor and cylinders, above

oil pump.

Sensors are installed directly in refrigerant or water circuit. Relieve all refrigerant pressure or drain water before removing.

Proceed as follows (refer to Fig. I I):

Remove and discard original sensor and coupling.

IMPORTANT: Do not disassemble new install as received.

couphng;

2. Apply pipe sealant to I /4-in. NPT threads on replacement coupling and install in place of original. Do not

use packing nut to tighten coupling; this would

damage ferrules (see Fig. I I

3. Insert new sensor in coupling body to its full depth. Hand tighten packing nut to position ferrules, then

finish tightening I-1/4 turns with a suitable tool.

Ferrules are now attached to sensor, which can be

withdrawn from coupling for unit servicing.

FERRULES INSIDE

COUPLING

/ASSEMBLY

CABLE ASSEMBLY

FERRULES SENSOR

2$70mm)

Fig. 11- Thermistor (Compressor and Cooler)

‘f

. II

COUPLING BODY

Page 23

Modules

Turn controller power off before servicing

tha

controls. This is to ensure safety and prevent damage to the controller.

PROCESSOR MODULE (PSIO), LOW-VOLTAGE RELAY MODULE (DSIO) AKD EXV DRIVER MODULE (DSlO) - The

PSI0

and DSIO modules all perform continuous diagnostic evaluations of the condition of the hardware. Proper operation of these modules is indicated by LEDs (light emitting diodes) on the front surface of the DSlOs and on the top horizontal surface of the PSIO.

Red LED:

B/inking

c.ontinuous1.i.

at a 3 to 5 second rate indicates

proper operation

Lit

covzlinrrous/~r~

indicates a problem requiring replace-

ment of the module

Qf~corttinuous(~~

indicates the power

shouId

be checked. If there is no input power, check fuses. If fuse is bad, check for shorted secondary of transformer, or for bad module.

Green LED: (On a PSIO, this is the green LED closest to

the COMM connectors. The other green LED on the module indicates external communications, when used.)

The green LED should always be blinking

when patvcr is on; it indicates that the modules are communicating

properly. If a green LED is not blinking, check

the red

LED. If the red LED is normal, check the module address

switches. See Fig. 9. The proper addresses are:

PSI0

(Processor Module) ~ 00

DSIC) (Relay Module) ~ 32 I”~610

[IiXV Driver Module) -- 50

a]]

the COM hq

sists, replacr the

modules indicate a communication failure, check

lf^ :r good

only a

~)l~tg on

the

connection is

PSI0

ITS;;10

module indicates a communication

PSI0

module for proper seating.

assured

and the condition per-

module.

failure, check the COhlM plug on that module for proper

seating. If a good connection is assured and the condition

persists.

module (processor

the unit. This

All

rcpIace

the

DSl0

module.

system

operating inteiligcnce rests in the

mod&

moddej,

the modttlc that controls

monitors conditions through input

PSI0

and output ports and through tire DSlO modules (low- voltage relay module and I:XV

driv!er

module).

The machine operator communicates with the micro-

processor through

module). Communication between other modules is accomplished by a These 3 wires run in

the IIS

p~trallel

module (keyboard;!dinplay

the PSI0

3-vvire ~tn~or

and the

bus.

from module to module.

Each module in a panel is numbered (1. 2, 3,..). Each terminal strip on a module is labeled (J2, J3,

.J4...).‘I’he

terminal strip number on the machine schematic combines the module and strip numbers. For example, 253 is

terminal strip 53 on module 2. The module numbers can be found on the component arrangement label.

Fig.

‘l2 -

Module Address Selector Switch

Locations

PSlO

ADDRESS SELECTOR

Page 24

On the sensor bus terminal strips, terminal 1 of the

PSI0

module is connected to terminal 1 of each of the other modules; terminals 2 and 3 are connected in the same manner. (See Fig. 13.) If a terminal 2 wire is connected to terminal 1, the system will not work.

in the 30HK,HS units, the processor module, low- voltage relay module, and keyboard! display module are all powered from a common 21 vat power source which connects to terminals 1 and 2 on the power input strip of each module. A separate source of 12.5 vat power is used to power the EXV driver module through terminals 1 and 2 on the power input strip.

PSI0

DSIO

(RELAY)

DSIO

(EXV DRIVER)

Fig. 13 - Sensor Bus Wiring

HSIO

Processor Module (PSIO) (Fig. 14.)

Inputs

Each input channel has 3 terminals; only 2 of the 3 terminals are used. The application of the machine determines which terminals are used. Always refer to the individual unit wiring for terminal numbers.

Outputs ~

Output is 24 vdc. Again, there are 3 terminals, only 2 of which are used; which 2 depends on the application. Refer to unit wiring diagram.

NOTE: Both address switches must be set at zero.

CHASS IS

GROUND

mm*

-r-awe4

(REAR1

NETWORK

sfNNECTOR

Low-Voltage Relay Module (DSIO) (Fig. 15.)

r#2j?2rt.s

OFF).

Inputs on strip

When

24 vat are applied

a channel it is

read

as an ON signal, Zero

.J3

arc discrcti: inputs (ON-

itcross the

2 tcrminah in

vnl$s

is read

as an OFF signal.

0ulput.s -

Terminal strips 54 and

.J5

are internal relays

whose coils are powered-up and powered-off by a signal from the microprocessor. The relays switch the circuit to

which they are connected. No power is supplied to these connections by the DSIO module.

SENSOR BUS CONNECTOR

INPUTS : 24 VAC

CHANNEL I - J3 PINS

2,4,6 88

COMMON

%fMoN

,%~MON

&MON

23- I

ARE GROUND (C1

CHANNEL

18 2

384

586

788

C%MoN

C&MON

COMMON

C&MON

Fig, 15 - Low-Voltage Relay Module (DSIO)

ADDRESS ADJUSTMENT (NOT SHOWNI ON UNDERSIDE.

‘(FORWARD)

ADDRESS SW trcnEs

PSI0

’

--l 0

SENSOR BUS

58” NECToR

Fig. 14 - Processor Module (PSiO)

Page 25

EXV Driver Module (Fig. 16.)

Inputs

When 24 vat are applied channel it is read as an ON signal. Zero

Input on strip 32 am-c discrcre inputs (O?;-OFF).

across thy

2 terminals in a

voIts

is read as

an OFF signal.

Outputs ~

Two stepper motor driver outputs

;tre

used to drive the electronic expansion valves, Terminals I and 7 supply voltage to the valves. Terminals 2 through 5 and through 1 I connect the individual coils (4 per valve) to neutral in a repeating sequence to drive the valves in incremental steps.

SENSOR BUS CONNECTOR

Keyboard! Display Module (HSIO) (Fig.

function of the HSIO is to allow the operator

municate with the processor. It is used to enter

tions

and set points and to read data, perform tests and

set

schedules.-

17) ‘~‘he I(.) cr)&*

confiyt~ra-

onlv

RED STATUS LIGHT

;iREEN COMMUNICATION LtGHT

STEPPER

MOTOR 2

STEPPER MOTOR I

ADDRESS ADJUSTMENT

-I=

(NOT SHOWN~

2,4,6EiBARE

COIL 4

COMMON

ON UNDERSIDE

GROUND(C)

Fig. 16 - EXV Driver Module (DSIO)

Fig. 17 - Keyboard/Display Module (I-ISIO)

Page 26

TROUBLESHOOTING

SYMPTOMS Compressor does

not run

cycles off on toss of charge

Compressor shuts down on high-pressure control

CAUSE REMEDY Power

line open

Control fuse open

Safety thermostat

tripped (DGT)

Tripped power

breaker

lating

pump not

Improperly wired

controls Low line voltage

Compressor motor defective

Seized compressor Loss of charge control 1 Repair leak;Compressor

erratic in action

Low refrigerant charge Add refrigerant.

High-pressure control Replace control.

erratic in action

Compressor discharge

valve partially closed Air in system Condenser scaled Receiver not properly

vented - refrigerant backs up into evap condenser

Condenser water pump

or fans not operating replace if defective.

Reset circuit breaker. Check control circuit

for ground or short. Replace fuse.

Move RUN/STANDBY switch to STANDBY, then back to RUN.

Check the controls.

Find cause of trip and reset breaker.

Check wiring and

rewire. Check line voltage

determine location of voltage drop and

remedy deficiency. Check motor winding

for open or short.

Replace compressor,

necessary.

Reolace

comPressor.

I-

Open valve, or

place

if defective.

1 Purge.

Clean condenser.

Repipe as required,

providing adequate

venting.

Start pump- repairor

re-

SYMPTOMS CAUSE Unit operates

long or continuously

Service load

System Noises

Compressor noisy 1 Check valve plates

Compressor loses

oil

Frosted suction line

Hot

liquid

line

Frosted liquid line

Compressor will not unload

Expansion valve

restricted Restricted

filter

drier

control

valve

REMEDY

for valve noise.

ReDlace

comDressor

(w&n bearings)

Check for loose compressor down bolts.

relay contacts. Check cooler and

Remove restriction

hold-

Compressor will not load

control valve Plugged strainer

(high side)

Clean or replace strainer.

Page 27

Page 28

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Book 2 Tab 5c

--I-

PC111

Catalog No. 533-030 Printed in U.S.A. Form30HR,HS-1T Pg 28 l-89 Replaces: New