Carrier 48/50AJ specifications Troubleshooting, Time Clock Configuration

Table 93 — Time Clock Configuration

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

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.

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