Carrier HS070-160 User Manual

Page 15

KEYBOARD

DISPLAY

ENTRY

RESPONSE

q u

COMP

OFF

CA1 ON

OFF

C A 2 O F F

END TEST

COMMENTS

Factory field test of compressors

subfunction of test function

Circuit A, compressor test

Pressing

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

o f f

Pressing the down arrow key advances

the system to circuit A, compressor 2 test

If no other test desired, exit quick test

Refer to Fig.

and 7 for specific control wiring. Each

module in a panel is numbered

Each terminal

strip is labeled

The terminal strip on the

machine schematic combines the module and strip

numbers. For example,

is terminal strip

o n

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

T h e

subfunction checks the thermistor and

switch inputs. The thermistor tests display the tempera-
ture 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

terminal (the entire connector can be pulled from

the

by pulling the connector to the left). Read the

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 cor-
responds to that resistance; this temperature should

appear in the Quick Test display.

Loss of charge and oil pressure switch tests show

if the switch is

and NRM or SAFE 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.

T h e

subfunction will energize the control

outputs except for the compressor control outputs. (See

Fig. 6.)

The liquid line solenoid and unloader solenoid tests

will energize the output when

is pressed. It will

remain energized until either the

key is pressed or

10 minutes have elapsed. When the processor energizes

the output

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.

T h e

subfunction energizes the compressor

control relays for 10 seconds and displays the compressor

status feedback.

The liquid line solenoid in the same circuit will ener-

gize 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

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

compressor does not start, check the control relay,

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

if used), continuity across the

terminals

and interconnecting wiring.

To protect the compressors from repeated cycling, a

delay of one minute is required before the same com-
pressor is retested.

The

subfunctions take the unit out of the

Quick Test mode. Press

and the display will

show

TEST; press

and the display blinks and

then shows END TEST again.