Carrier 040-420 specifications Example 1 Reading Alarm Codes, Operationat and Mode Display Codes

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.

i

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
ENTRY	RESPONSE
	‘MvoEo;2;;5	Keypad has not been used for
		at least 10 minutes. Alternating
	0 STAGES	summary display appears on
	2 ALARMS	screen
p-jq	2 ALARMS	2 alarms detected
cl	ALARM 9	First alarm code
+
EXPH	COOLER LEAVING
	FLUID THERMISTOR	Explanation of alarm	code
0	FAILURE
4	ALARM 42	Second alarm code Cooler
Ll		freeze protection
EXPN	COOLER FREEZE	Explanation of alarm	code
0	PROTECTION

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
		Unit is off. LOCAL/ENABLE-STOP-CCN switch is
LOCAL OFF		in OFF position, or LOCAL/ENABLE-STOP-CCN
		switch may be in LOCAL position with external ON/
		OFF switch in OFF position
CCN OFF		Unit is off due to CCN network command. LOCAL/
		ENABLE-STOP-CCN switch is in CCN position.
CLOCK OFF		Unit is off due to internal clock schedule. LOCAL/
		ENABLE-STOP-CCN switch is in LOCAL position.
		Unit is on. LOCAL/ENABLE-STOP-CCN switch is
LOCAL ON		in LOCAL position If external ON/OFF switch is used,
		it will be in ON bosition.
CCN ON		Unit is on due to CCN command LOCAUENABLE-
		STOP-CCN switch is in CCN position.
		Unit is on due to internal clock schedule or occu-
CLOCK ON		pied override function. LOCALIENABLE-STOP-
		CCN switch is in LOCAL position.
		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
		level (CSP2 set Point is in SET function)
		Temperature reset is in effect. In this mode, unit is
		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
		based on return water, outdoor-air temperature or
		space temperature
		Demand limit is in effect. This indicates that ca-
		pacity of unit is being limited by demand limit con-
MODE 9		trol option Because of this limitation, unit may
		not be able to produce the desired leaving water
		temperature
		Load limit is in effect. This indicates that capacity of
		a system of units is being limited by a CCN load-
MODE 10		shed command Due to this limitation, unit may
		not be able to produce the desired leaving water
		temperature.
MODE	II	Not aoalicable.I I
		Ramp load (pulldown) limiting is in effect. In this mode,
		the r&e at which leaving water temperature is dropped
		is limited to a predetermined value to prevent com-
MODE	12	pressor overloading, See CRAMP set point in the
		SET function in Table 9 The pulldown limit can be
		modified, if desired, to any rate from 2 F to 2 F
		( lo to lo Q/minute
		Timed override is in effect This is a 1 to 4 hour
		temporary override of the programmed schedule,
MODE	13	forcing unit to occupied mode Override can be im-
		plemented with unit under LOCAL or CCN control
		Override expires after each use
		Low cooler suction protection is in effect In this mode,
		circuit capacity is not allowed to increase if cooler
		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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