REPLACING THERMISTORS T1, T5, T6, T7, AND T8 —
Add a small amount of thermal conductive grease to ther-
mistor well. Thermistors are friction-fit thermistors, which
must be slipped into receivers located in the cooler leaving
fluid nozzle for T1, in the cooler head for T5 and T6 (EXV
units only), and in the compressor pump end for T7 and T8
(EXV units only).
THERMISTORS T3 AND T4 — These thermistors are lo-
cated on header end of condenser coil. They are clamped on
a return bend.
THERMISTOR/TEMPERATURE SENSOR CHECK — A
high quality digital volt-ohmmeter is required to perform this
check.
1. Connect the digital voltmeter across the appropriate
thermistor terminals at the J8 terminal strip on the Main
Base Board for thermistors T1-T6, T9, T10; or the J5 ter-
minal strip on the EXV Board for thermistors T7 and T8
(see Fig. 31). Using the voltage reading obtained, read
the sensor temperature from Tables 30A-31B. To check
thermistor accuracy, measure temperature at probe loca-
tion with an accurate thermocouple-type temperature mea-
suring instrument. Insulate thermocouple to avoid ambi-
ent temperatures from influencing reading. Temperature
measured by thermocouple and temperature determined
from thermistor voltage reading should be close, ± 5° F
(3° C) if care was taken in applying thermocouple and
taking readings.
2. If a more accurate check is required, unit must be shut
down and thermistor removed and checked at a known
temperature (freezing point or boiling point of water) us-
ing either voltage drop measured across thermistor at
the J8 or J5 terminals, by determining the resistance with
chiller shut down and thermistor disconnected from J8 or
J5. Compare the values determined with the value read
by the control in the Temperatures mode using the Mar-
quee display.
1
2
3
4
1
2
3
4
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
BLU
BLU
PNK
PNK
TB5
TB5
TB5
TB5
5
6
7
8
T10
T9
REMOTE SPACE TEMP
(ACCESSORY)
5
6
7
8
9
10
1
2
3
4
1
2
3
4
5
6
1
2
3
4
5
6
2
1
4
6
3
5
T5
T3
T4
T6
T2
T1
COOLER ENTERING
FLUID TEMP
OUTDOOR-AIR TEMP
(ACCESSORY)
COOLER LEAVING
FLUID TEMP
SATURATED
CONDENSING TEMP-
CIRCUIT B
SATURATED
SUCTION TEMP-
CIRCUIT B*
SATURATED
CONDENSING TEMP-
CIRCUIT A
SATURATED
SUCTION TEMP-
CIRCUIT A*
MAIN BASE BOARD
J8
T1-T6, T9, T10 THERMISTORS
J5
EXV BOARD
12
11 10
9
8
7
6
5
4
3
2
1
12 11
10
9
T8
8
T7
7
CKTA*
CKTB*
COMPRESSOR RETURN GAS TEMP
T7, T8 THERMISTORS
*Not used on FIOP (Factory-Installed Option) unit with TXV (Ther-
mostatic Expansion Valve).
Fig. 31 — Thermistor Connections to J5 and J8
Processor Boards
58
Содержание 30GTN
Страница 6: ...Fig 1 Typical Control Box 080 110 and Associated Modular Units Shown 6 ...
Страница 7: ...Fig 2 24 V Control Schematic Unit Sizes 040 070 7 ...
Страница 8: ...Fig 3 24 V Control Schematic Unit Sizes 080 110 230B 315B 8 ...
Страница 9: ...Fig 4 24 V Control Schematic Unit Sizes 130 210 230A 315A 330A B 420A B 9 ...
Страница 75: ......