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77
Table 93 — Time Clock Configuration
TROUBLESHOOTING
The scrolling marquee display shows the actual operating
conditions of the unit while it is running. If there are alarms or
there have been alarms, they will be displayed in either the cur-
rent alarm list or the history alarm list. The Service Test mode
allows proper operation of the compressors, fans, and other
components to be checked while the unit is not operating.
Complete Unit Stoppage — There are several condi-
tions that can cause the unit not to provide heating or cooling.
If an alarm is active which causes the unit to shut down,
diagnose the problem using the information provided in
the Alarms and Alerts section on page 93, but also check for
the following:
• Cooling and heating loads are satisfied.
• Programmed schedule.
• General power failure.
• Tripped control circuit transformers circuit breakers.
• Tripped compressor circuit breakers.
• Unit is turned off through the CCN network.
Single Circuit Stoppage — If a single circuit stops
incorrectly, there are several possible causes. The problem
should be investigated using information from the Alarms and
Alerts section on page 93.
Service Analysis — Detailed service analysis can be
found in Tables 94-96 and in Fig. 14.
Restart Procedure — Before attempting to restart the
machine, check the alarm list to determine the cause of the
shutdown. If the shutdown alarm for a particular circuit has
occurred, determine and correct the cause before allowing the
unit to run under its own control again. When there is problem,
the unit should be diagnosed in Service Test mode. The alarms
must be reset before the circuit can operate in either Normal
mode or Service Test mode.
Thermistor Troubleshooting — The electronic con-
trol uses five 5K-thermistors for the saturated condensing
temperature on 48/50AJ,AK,AW,AY units (SCT.A and
SCT.B). See Tables 97 and 98 for temperature vs. resistance
data.
When replacing thermistors SCT.A and SCT.B, reuse the
original hardware. These thermistors must be clamped tightly
to the hairpins of the condenser.
The EDT, OAT, RAT, LAT, T55, T56, and T58 space tem-
perature sensors use 10K thermistors. Resistances at various
temperatures are listed in Tables 99 and 100.
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.
2. Using the voltage reading obtained, read the sensor tem-
perature from Tables 97-100.
3. To check thermistor accuracy, measure temperature at
probe location with an accurate thermocouple-type
temperature-measuring instrument. Insulate thermocou-
ple to avoid ambient 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.
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) using either voltage
drop measured across thermistor at the J8 terminal, or by deter-
mining the resistance with unit shut down and thermistor dis-
connected from J8. Compare the values determined with the
value read by the control in the Temperatures mode using the
scrolling marquee display.
ITEM EXPANSION RANGE POINT DEFAULT
TIME TIME OF DAY
HH.MM Hour and Minute 00:00 TIME
DATE MONTH,DATE,DAY AND YEAR
MNTH Month of Year multi-text strings MOY
DOM Day of Month 0-31 DOM
DAY Day of Week multi-text strings DOWDISP
YEAR Year e.g. 2003 YOCDISP
SCH.L LOCAL TIME SCHEDULE
PER.1 PERIOD 1
PER.1
DAYS DAY FLAGS FOR PERIOD 1 Period 1 only
PER.1
DAYS
MON Monday in Period YES/NO PER1MON Yes
PER.1
DAYS
TUE Tuesday in Period YES/NO PER1TUE Yes
PER.1
DAYS
WED Wednesday in Period YES/NO PER1WED Yes
PER.1
DAYS
THU Thursday in Period YES/NO PER1THU Yes
PER.1
DAYS
FRI Friday in Period YES/NO PER1FRI Yes
PER.1
DAYS
SAT Saturday in Period YES/NO PER1SAT Yes
PER.1
DAYS
SUN Sunday in Period YES/NO PER1SUN Yes
PER.1
DAYS
HOL Holiday in Period YES/NO PER1HOL Yes
PER.1
OCC Occupied from 00:00 PER1_OCC 00:00
PER.1
UNC Occupied to 00:00 PER1_UNC 24:00
Repeat for periods 2-8
HOL.L LOCAL HOLIDAY SCHEDULES
HD.01 HOLIDAY SCHEDULE 01
HD.01
MON Holiday Start Month 0-12 HOL_MON1
HD.01
DAY Start Day 0-31 HOL_DAY1
HD.01
LEN Duration (Days) 0-99 HOL_LEN1
Repeat for holidays 2-30
DAY.S DAYLIGHT SAVINGS TIME
DS.ST DAYLIGHT SAVINGS START
DS.ST
ST.MN Month 1 - 12 STARTM 4
DS.ST
ST.WK Week 1 - 5 STARTW 1
DS.ST
ST.DY Day 1 - 7 STARTD 7
DS.ST
MIN.A Minutes to Add 0 - 90 MINADD 60
DS.SP DAYLIGHTS SAVINGS STOP
DS.SP
SP.MN Month 1 - 12 STOPM 10
DS.SP
SP.WK Week 1 - 5 STOPW 5
DS.SP
SP.DY Day 1 - 7 STOPD 7
DS.SP
MIN.S Minutes to Subtract 0 - 90 MINSUB 60