![Example 1 - Reading Alarm Codes](/images/new-backgrounds/33889/3388973x1.webp)
STATUS FUNCTION - This function shows the rotating display, current status of alarm (diagnostic) codes, capacity stages, operating modes, chilled water set point, all meas- ured system temperatures and pressures, superheat values, pressure switch positions, analog inputs, and switch inputs .
These subfunctions are defined on pages 37 and 38.
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m(R oFita t i n g D i s p l a y )
(AlarmFis) - Alarms are messages that one or more faults have been detected. Each fault is assigned a code num- ber which is reported with the alarm. See Table 10 for code definitions. The codes indicate failures that cause the unit to shut down, terminate an option (such as reset) or result in the use of a default value as set point.
Up to 5 alarm codes can be stored at once. To view them
in sequence, press mm to enter the alarm displays and then press q to move to the individual alarm dis-
plays. Press q after a code has been displayed. The mean- ing of the code scrolls across the screen. See Example 1
Example 1 - Reading Alarm Codes
K E Y P A D | DISPLAY | COMMENTS |
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ENTRY | RESPONSE |
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| ‘MvoEo;2;;5 | Keypad has not been used for | |
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| at least 10 minutes. Alternating | |
| 0 STAGES | summary display appears on | |
| 2 ALARMS | screen |
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| 2 ALARMS | 2 alarms detected |
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cl | ALARM 9 | First alarm code |
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+ |
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EXPH | COOLER LEAVING |
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FLUID THERMISTOR | Explanation of alarm | code | |
0 | FAILURE |
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4 | ALARM 42 | Second alarm code Cooler | |
Ll |
| freeze protection |
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EXPN | COOLER FREEZE | Explanation of alarm | code |
0 | PROTECTION |
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When a diagnostic (alarm) code is stored in the display and the machine automatically resets, the code is deleted. Codes for safeties which do not automatically reset are not deleted until the problem is corrected and the machine is switched to STOP, then back to LOCAL/ENABLE or CCN.
mbi (Modes) - The operating mode codes are dis- played to indicate the operating status of the unit at a given time. See Table 10.
Table 10 - Operationat and Mode Display Codes
The operating modes are displayed by name or code num- ber, to indicate the operating status of the unit at a given time. The modes are:
CODE | 1 | DESCRlPTlON | ||
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| Unit is off. | ||
LOCAL OFF | in OFF position, or | |||
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| switch may be in LOCAL position with external ON/ | ||
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| OFF switch in OFF position | ||
CCN OFF | Unit is off due to CCN network command. LOCAL/ | |||
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CLOCK OFF | Unit is off due to internal clock schedule. LOCAL/ | |||
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| Unit is on. | ||
LOCAL ON | in LOCAL position If external ON/OFF switch is used, | |||
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| it will be in ON bosition. | ||
CCN ON | Unit is on due to CCN command LOCAUENABLE- | |||
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| Unit is on due to internal clock schedule or occu- | ||
CLOCK ON | pied override function. | |||
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| CCN switch is in LOCAL position. | ||
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| Dual set point is in effect In this mode, unit contin- | ||
M O D E | 7 | ues to run in unoccupied condition, but leaving wa- | ||
ter set point is automatically increased to a higher | ||||
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| level (CSP2 set Point is in SET function) | ||
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| Temperature reset is in effect. In this mode, unit is | ||
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| using temperature reset to adjust leaving water set | ||
MODE 8 | point upward, and unit is currently controlling to the | |||
modified set point. The set point can be modified | ||||
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| based on return water, | ||
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| space temperature | ||
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| Demand limit is in effect. This indicates that ca- | ||
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| pacity of unit is being limited by demand limit con- | ||
MODE 9 | trol option Because of this limitation, unit may | |||
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| not be able to produce the desired leaving water | ||
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| temperature |
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| Load limit is in effect. This indicates that capacity of | ||
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| a system of units is being limited by a CCN load- | ||
MODE 10 | shed command Due to this limitation, unit may | |||
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| not be able to produce the desired leaving water | ||
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| temperature. |
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MODE | II | Not aoalicable.I I |
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| Ramp load (pulldown) limiting is in effect. In this mode, | ||
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| the r&e at which leaving water temperature is dropped | ||
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| is limited to a predetermined value to prevent com- | ||
MODE | 12 | pressor overloading, See CRAMP set point in the | ||
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| SET function in Table 9 The pulldown limit can be | ||
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| modified, if desired, to any rate from 2 F to 2 F | ||
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| ( lo to lo Q/minute | ||
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| Timed override is in effect This is a 1 to 4 hour | ||
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| temporary override of the programmed schedule, | ||
MODE | 13 | forcing unit to occupied mode Override can be im- | ||
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| plemented with unit under LOCAL or CCN control | ||
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| Override expires after each use | ||
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| Low cooler suction protection is in effect In this mode, | ||
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| circuit capacity is not allowed to increase if cooler | ||
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| saturated suction temperature is 20” F (11” C) for | ||
MODE |
| ’water or 30” F | (16” C) for brine or more below l e a v - | |
| ing fluid temperature, and saturated suction tem- |
14perature is less than 32 F (0’ C). If these conditions persist beyond 10 minutes, circuit is shut down and fault code 44 or 45 is displayed.
CCN - CarrierComfort Network
To enter the MODES subfunction, depress MFI and use the q key to determine if more than one mode ap- plies. See Example 2 to read current mode with expansion.
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