Carrier 69NT40-541-306 Operation And Service Download

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4–21

T-354

Cd28

Temperature Units
(Degrees C or
Degrees F)

This code determines the temperature units (



C or



F) which will be used for all

temperature displays. The user selects



C or



F by selecting function code

Cd28 and pushing the ENTER key. The factory default value is Celsius units.

NOTE

This code will display "

-----"

if Configuration Variable CnF34 is set to



Cd29 Failure Action (Mode)

If all of the control sensors are out of range (alarm code AL26) or there is a
probe circuit calibration failure (alarm code AL27), the unit will enter the shut-
down state defined by this setting. The user selects one of four possible actions
as follows:

A - Full Cooling (stepper motor SMV at maximum allowed opening)

B - Partial Cooling (stepper motor SMV 11% open)

C - Evaporator Fan Only

D - Full System Shutdown - Factory Default

Cd30 In-Range Tolerance

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



2 = +/- 1.0



C (+/-1.8



3 = +/- 1.5



C (+/-2.7



4 = +/- 2.0



C (+/-3.6



F) - Factory Default

Cd31

Stagger Start Offset
Time (Seconds)

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 powered up together. The eight possible offset values are:

0 (Factory Default), 3, 6, 9, 12, 15, 18 or 21 seconds

Cd32 Current Limit (Amperes)

The current limit is the maximum current draw allowed on any phase at any
time. Limiting the unit's current reduces the load on the main power supply. This
is ac complished by reducing the SMV position until current draw is reduced to
the set point. When desirable, the limit can be lowered. Note, however, that ca-
pacity is also reduced. The five values for 460VAC operation are:

15, 17, 19, 21 (Factory Default), 23

Cd33

Perishable Mode
Dehumidification
/Humidification
Control (% RH)

Relative humidity set point is available only on units configured for dehumidifi-
cation. 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 dis play. The

value can be set to "OFF." "TEST," or a range of 65 to 95% relative humidity in
increments of 1%. [If bulb mode is active (code Cd35) and "Lo" speed evaporator
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 illumi-
nate, indicating that dehumidification mode is activated. After a period of five min-
utes in the "TEST" mode has elapsed, the previously selected mode is reinstated.

NOTE

If humidification (CnF35) is enabled, then humidification will be enabled and
dehumidification locked out at set points of 75% and above. At set points be
low 75%, dehumidification will be enabled and humidification locked out.

Cd34

Economy Mode
(On-Off)

Economy mode is a user selectable mode of operation provided for power sav-
ing purposes.

Table 4–5 Controller Function Codes (Continued)

CODE

TITLE

DESCRIPTION