Carrier 69NT40-561-019 Operation And Service Manual page 53

CODE # TITLE
Failure Action
Cd29
(Mode)
In-Range
Cd30
Tolerance
Stagger Start
Cd31 Offset Time
(Seconds)
Current Limit
Cd32
(Amperes)
Perishable Mode
Cd33 Dehumidification
Control (% RH)
Economy Mode
Cd34
(On-Off)
Cd35 Bulb Mode
Evaporator
Cd36
Speed Select
Table 4–5 Controller Function Codes (Continued)
If all of the control sensors are out of range (alarm code AL26) or there is a probe cir-
cuit calibration failure (alarm code AL27), the unit will enter the shutdown state de-
fined by this setting. The user selects one of four possible actions as follows:
A - Full Cooling (Compressor is on, economized operation.)
B - Partial Cooling (Compressor is on, standard operation.)
C - Evaporator Fan Only (Evaporator fans on high speed, not applicable with frozen
set points.)
D - Full System Shutdown - Factory Default (Shut down every component in unit.)
The in-range tolerance will determine the band of temperatures around the set point
which will be designated as in-range. If the control temperature is in-range, the in-
range light will be illuminated. There are four possible values:
1 = +/- 0.5°C (+/- 0.9°F)
2 = +/- 1.0°C (+/- 1.8°F)
3 = +/- 1.5°C (+/- 2.7°F)
4 = +/- 2.0°C (+/- 3.6°F) - Factory Default
The stagger start offset time is the amount of time that the unit will delay at start-up,
thus allowing multiple units to stagger their control initiation when all units are pow-
ered up together. The eight possible offset values are:
0 (Factory Default), 3, 6, 9, 12, 15, 18, or 21 seconds
The current limit is the maximum current draw allowed on any phase at any time. Lim-
iting the unit's current reduces the load on the main power supply. When desirable,
the limit can be lowered. Note, however, that capacity is also reduced. The five values
for 460 VAC operation are: 15, 17, 19, 21, or 23 amperes. The factory default setting
is 21 amperes.
Relative humidity set point is available only on units configured for dehumidification.
When the mode is activated, the control probe LED flashes on and off every second
to alert the user. If not configured, the mode is permanently deactivated and "-----" will
display. The value can be set to "OFF," "TEST," or a range of 65 to 95% relative hu-
midity in increments of 1%. [If bulb mode is active (code Cd35) and "Lo" speed evap-
orator motors are selected (code Cd36), then set point ranges from 60 to 95%.] When
"TEST" is selected or test set point is entered, the heat LED should illuminate, indi-
cating that dehumidification mode is activated. After a period of five minutes in the
"TEST" mode has elapsed, the previously selected mode is reinstated.
Economy mode is a user selectable mode of operation provided for power saving pur-
poses.
Bulb mode is a user selectable mode of operation that is an extension of dehumidifi-
cation control (Cd33). If dehumidification is set to "Off," code Cd35 will display "Nor"
and the user will be unable to change it. After a dehumidification set point has been
selected and entered for code Cd33, the user may change code Cd35 to "bulb." After
bulb has been selected and entered, the user may utilize function codes Cd36 and
Cd37 to make the desired changes.
This code is enabled only if in the dehumidification mode (code Cd33) and bulb mode
(Cd35) has been set to "bulb." If these conditions are not met, "alt" will be displayed
(indicating that the evaporator fans will alternate their speed) and the display cannot
be changed. If a dehumidification set point has been selected along with bulb mode,
"alt" may be selected for alternating speed, "Lo" for low speed evaporator fan only, or
"Hi" for high speed evaporator fan only. If a setting other than "alt" has been selected
and bulb mode is deactivated in any manner, the selection reverts back to "alt."
DESCRIPTION
4–27 T-359