Carrier 48DK024 Controls Operation And Troubleshooting page 19

IMPORTANT: Once quick test is initiated, display but-
ton must be pressed at least once every 10 minutes for
control to remain in quick test mode. If button is not
pressed within this time, control will attempt to start
the unit.
To recheck any step in quick test program, control must
be recycled by turning unit control switch off for a few sec-
onds, and then turning it back on again. Restart quick test
program as described above and proceed through quick test
steps. Press display button twice for each step until step to
be rechecked is reached.
The quick test program is divided into 3 sections as de-
scribed below and shown in Tables 8-10.
1. Quick Test Steps 1.-1.3. — Unit Configuration and Switch
Check
The microprocessor in unit control system is programmed
by 2 switch assemblies located on processor board
(Fig. 1). The configuration header is factory set and can-
not be changed in the field. The DIP switch assembly con-
tains 8 microswitches that must be set in accordance with
QUICK
TEST
STEP NO.
1.
2.
3.
4.
5.
6.
7.
8.
9.
1.0.
1.1.
1.2.
1.3.
LEGEND
DIP — Dual, In-Line Package
EC — Enthlapy Contol
ECR — Enthalpy Control
VAV — Variable Air Volume
*Units are not equipped with oil pressure switches.
Table 8 — Quick Test, Unit Configuration and Switch Check
NORMAL
DISPLAY
01
Type Unit — Air-Cooled VAV
2
No. of Compressors
No. of Unloaders
2
(024-034, 054-074)
1
(044)
60
60-Hertz Power
0 — No Reset (Switch Off)
0 or 1
1 — Reset On (Switch On)
0 — No Economizer (Switch Off)
0 or 1
1 — Economizer On (Switch On)
0 — No Warm-Up (Switch Off)
0 or 1
1 — Warm-Up Used (Switch On)
0 — Demand Limit Not Used
0 or 1
(Switch Off)
1 — Demand Limit Used
(Switch On)
0 — Enthalpy Switch Open
0 or 1
1 — Enthalpy Switch Closed
1 — Low-Pressure Switch Closed
1
1 — Low-Pressure Switch Closed
1
1
No Circuit 1 Oil Pressure Switch
1
No Circuit 2 Oil Pressure Switch
the various options selected by the customer. All DIP
switches should be checked and set to proper position for
options selected prior to the quick test. See Configuration
of Header and DIP Switch Assembly section on page 5
for factory switch settings. The DIP switch functions and
display codes are shown in Table 8.
2. Quick Test Steps 1.4.-2.3. — Thermistor and Set Point
Potentiometers
In these steps, the microprocessor checks resistance val-
ues of all sensors and set point potentiometers to ensure
that they are functional, connected properly, and set within
proper range for unit configuration.
Nominal resistance values for all sensors range from 363,000
to 219 ohms in accordance with Table 11. Normal dis-
play code for good sensors and potentiometers is 1. A dis-
play code of 0 indicates a faulty potentiometer, thermistor
or wiring. A 0 display also indicates that option is not
being used.
Table 9 shows thermistor and set point potentiometer func-
tions and quick test display codes.
DESCRIPTION
19
CONTROL SWITCH
Configuration Header
Configuration Header
DIP Switch No. 6 and 7
Configuration Header
DIP Switch No. 2
DIP Switch No. 3
DIP Switch No. 4
DIP Switch No. 5
ECR (024-030)
EC (034-074)
Jumper (024-030)
Low-Pressure Switch 1 (034-074)
Jumper (024-030)
Low-Pressure Switch 2 (034-074)
None*
None*