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General operating sequence, Occupancy determination – Carrier 48/50PD05 User Manual

Page 13

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RH Sensor On OAQ Input (RH.S)

This configuration identifies if a space relative humidity sensor is

installed on the outdoor air quality (OAQ) input. A YES value
enables SP.RH display. A NO value disables SP.RH display and

use.

Space Humidity Switch (RH.SW)

This configuration identifies if a space relative humidity switch is

installed on the ENTHALPY input, and what status (normally

open, normally closed) the input is when the space humidity is
LOW.

Temperature Compensated Start Cooling Factor

(TCS.C)

This factor is used in the equation of the Temperature

Compensated Start Time Bias for cooling. A setting of 0 minutes
indicates Temperature Compensated Start in Cooling is not

permitted.

Temperature Compensated Start Heating Factor

(TCS.H)

This factor is used in the equation of the Temperature
Compensated Start Time Bias for heating. A setting of 0 minutes

indicates Temperature Compensated Start in Heating is not

permitted.

General Operating Sequence

The PD unit must be connected to a space temperature sensor

T--55, T--56, T58 or T59 and will not operate with a conventional
R, Y1, Y2, W1, W2, G, C thermostat. When a T--55, T--56, T58 or

T59 space temperature sensor is connected to the low voltage

terminal board as shown in the Installation Instructions Manual, the
PD unit will try to maintain the Space Temperature

(TemperaturesAIR.TSPT) at one of four set points: The

Occupied Cool Set Point (SetpointsOCSP), the Unoccupied

Cool Set Point (SetpointsUCSP), Occupied Heat Set Point

(SetpointsOHSP), or the Unoccupied Heat Set Point

(SetpointsUHSP).

Occupancy Determination

When the building is in occupied mode, the occupied set points are
active. When the building is in unoccupied mode, the unoccupied

set points are active. The PD control will switch automatically

between cooling and heating to maintain temperature. However, to
minimize unnecessary cool to heat and heat to cool changes, there

is a 10--minute delay after the last stage turns off before the control
will switch modes. The heating and cooling set points are also

separated by a Heat--Cool Set Point Gap (SetpointsGAP) that is

user configurable from 2 to 10 degrees F. This parameter prevents

the unit from over cooling the conditioned space to where heating

mode is required or over heating the conditioned space to where
cooling mode is required.
The T55 space temperature sensor senses the temperature in the
conditioned space with no provisions for adjusting the space

temperature set point at the sensor. The T--56 space temperature

sensor senses the temperature in the conditioned space and allows
for adjustment of the space temperature set point by a configurable

number of degrees F higher or a configurable number of degrees F
lower at the space temperature sensor. The T58 space temperature

sensor communicates with the PD unit control board through a

CCN RS--485 +, --, and ground connection. The T59 space
temperature sensor is a T56 sensor with an integrated temperature

display. A jumper wire is not needed between R and W1 when
using space temperature sensors T55, T56, T58 or T59.
The building’s occupancy is affected by a number of different
factors. When the unit is operating with a space temperature sensor

(T--55, T--56, T--58 or T--59), occupancy affects the unit set points

and the operation of the economizer.

The factors affecting

occupancy are listed below from highest to lowest priority.

Level 1 Priority

The CCN point OCCUPIED is forced via an external device such

as a ComfortIDt controller: when OCCUPIED is forced to YES,
the unit is considered occupied, when OCCUPIED is forced to

NO, the unit is considered unoccupied. If OCCUPIED is not being
forced, proceed to the level 2 priority.

Level 2 Priority

Remote Occupancy Switch should be configured to either

Normally Open or Normally Closed when the user would like to
control the occupancy with an external switch. This switch is

field--supplied (24v, single pole, single throw [SPST]). There are
three possible configurations for the remote occupancy switch:

1. (ConfigurationUNITRM.SW = 0) No Switch
2. (ConfigurationUNITRM.SW = 1) Normally Open

Switch

3. (ConfigurationUNITRM.SW = 2) Normally Closed

Switch

If the switch is configured to No Switch (0), the switch input value

will be ignored and software will proceed to level 3 priority. For
each type of switch, the appropriate configuration and states are

listed in the table below.

TYPE OF SWITCH

SWITCH

CONFIGURATION

STATE OF

SWITCH AND

STATE OF

OCCUPANCY

Occupied when

Closed or

Unoccupied when

Open

Normal Open (1)

Open and

Unoccupied

Closed and

Occupied

Occupied when Open

Normal Closed (2)

Open and

Occupied

Unoccupied when

Closed

Normal Closed (2)

Closed and

Occupied

IMPORTANT: To perform remote occupancy, an Economizer
Control Board must be installed in the unit.

Level 3 Priority

The following occupancy options are determined by the state of

Occupancy

Schedule

Number

(ConfigurationCCNSCH.OSCH.N)

and

the

Global

Schedule Broadcast (ConfigurationCCNBRODB.GS).

1. (ConfigurationCCNSCH.OSCH.N = 0) The unit is

always considered occupied and the programmed schedule
is ignored. This is the factory default.

2. (ConfigurationCCNSCH.OSCH.N = 1- 64) Follow

the local programmed schedule. Schedules 1 to 64 are local

within the controller. The 48/50PD unit can only store one
local schedule and therefore changing this number only
changes the title of the schedule table.

3. (ConfigurationCCNSCH.OSCH.N

=

65- 99)

Follow the global programmed schedule. If the 48/50PD

unit is configured as a Global Schedule Broadcaster

(ConfigurationCCNRODB.GS = YES), the unit

will follow the unit’s programmed schedule and broadcast
the schedule so that other devices programmed to follow
this schedule number can receive the schedule. If the

48/50PD unit is not programmed as a Global Schedule
Broadcaster

(ConfigurationCCNBRODB.GS = NO), the unit

will receive broadcasted schedules from the unit
programmed to broadcast this schedule number. While

using the programmed schedule, occupancy can be
temporarily switched from unoccupied to occupied by

pressing the override button for approximately 3 seconds on
the T--55, T--56, T--58 or T--59 space temperature sensor.
Override will only occur if SPT Override Enabled

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50P

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