Features; Processor Module; L Low-Voltage Relay Module; Thermistors 2 - Carrier HS070-160 Troubleshooting Manual

Features

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 communi-
cates 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 main-
tain approximately 20 F of superheat entering t h e
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.
3 - RUN/STANDBY Switch
Pressure Gage Valves
5 - Suction
7 - Discharge Pressure Gages
8 - Compressor ON Lights
9 - Control Circuit
10
Fig. 1 - Control Panel
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.

control panel is shown in
8
9
Module
Fuses
EXV (ELECTRONIC EXPANSION VALVE)
MODULE -- The EXV driver module operates the elec-
tronic 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
erant charge, the EXV driver module detects a zero
voltage condition in the loss of charge switch electrical
circuit and communicates this information to the pro-
cessor 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 pro-
cessor 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
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 usage
in Table 1.
Table 1 - Keyboard and Display Madule
Key Usage
FUNCTION
K E Y S
OPERATIVE
K E Y S
q CLR
q t
2
DRIVER
a low refrig-
to
or low oil
Status - Displayjng diagnostic
codes
and current
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 Modei E machines
Service - Entering specific
unit configuration information
Set Point - Entering operating
set points and day/time
information
Schedule - Entering occupied/
schedules
unoccupied for unit
operation
USE
a
Expand Display - Displaying
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