Carrier 48/50Z030-105 TROUBLESHOOTING, Complete Unit Stoppage , Single Cir cuit Stoppage , Service Analysis , Restart Procedure , Thermisto r T r oubleshootin g

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Table 70 — Time Clock Menu
Daylight Savings Stop Week (DS.SP
→ SP.WK) — This is
the stop week of the month for daylight savings. The week can
be set from 1 to 5.
Daylight Savings Stop Day (DS.SP
→ SP.DY) — This is the
stop day of the week for daylight savings. The day can be set
from 1 to 7 (Sunday=1, Monday=2, etc.).
Daylight Savings Minutes To Subtract (DS.SP
→ MIN.S) —
This is the amount of time that will be removed from the time
clock after daylight savings ends.
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 operation of the compressors, fans, and other compo-
nents to be checked while the unit is not operating.
Complete Unit Stoppage — There are several condi-
tions that can cause the unit to not 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 94, 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 alarm and
alert list.
Service Analysis — Detailed service analysis can be
found in Tables 71-73 and Fig. 13.
Restart Procedure — Before attempting to restart the
machine, check the alarm list to determine the cause of the
shutdown. If a 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 EDT, OAT,
RAT, LAT, T55, T56, and T58 space temperature sensors use
10K thermistors. Resistances at various temperatures are listed
in Tables 74 and 75.
THERMISTOR/TEMPERATURE SENSOR CHECK — A
high quality digital volt-ohmmeter is required to perform this
check.
1. Connect the digital voltmeter across the appropriate ther-
mistor terminals at the J8 terminal strip on the main base
board.
2. Using the voltage reading obtained, read the sensor tem-
perature from Tables 74 and 75.
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 within 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
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