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Carrier WEATHERMAKER 48/50AJ User Manual

Page 38

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38

out a LOW COOL or a HIGH COOL mode and maintain a

low or high cool supply air set point.

C.TYP = 6 (SPT-2 STG)

This configuration will force the control to monitor the

space temperature sensor to make a determination of mode

and allow two stages of cooling.

MACHINE DEPENDENT CONFIGURATIONS — Some

configurations are linked to the physical unit and must not be

changed. The configurations are provided in case a field re-

placement of a board occurs and the settings are not preserved

by the download process of the new software. The following

configurations apply to all machine control types (C.TYP) ex-

cept 4 and 6. These configurations are located at the local dis-

play under Configuration

UNIT. See Table 44.

Table 44 — Machine Dependent Configurations

*Dependent on unit.

Unit Size (SIZE) — There are several unit sizes (tons) for the

A Series control. Make sure this configuration matches the size

called out by the model number of the unit. This is important as

the cooling stage tables are directly determined based on this

configuration.
Refrigerant Type (RFG.T) — This configuration specifies the

type of refrigerant used in the unit. Configuration RFG.T is set

to 0 if the refrigerant used is R-22. Configuration RFG.T is set

to 1 if the refrigerant used is R-410A. Make sure this configu-

ration matches the refrigerant called out by the model number

of the unit.
Condenser Type (CND.T) — This configuration specifies the

type of condenser installed in the unit. Configuration CND.T is

set to 0 if the condenser is a round tube, plate fin coil (RTPF).

Configuration CND.T is set to 1 if the condenser is a micro-

channel heat exchanger coil (MCHX). Make sure this configu-

ration matches the condenser type called out by the model

number of the unit.
SET POINTS — The set points for both cooling and heating

are located at the local display under Setpoints. See Table 45.

SUPPLY AIR RESET CONFIGURATION — Supply Air

Reset can be used to modify the current cooling supply air set

point. Supply Air Reset is applicable to control types, C.TYP =

1,2,3, and 5. The configurations for reset can be found at the

local display under Configuration

EDT.R. See Table 46.

EDT Reset Configuration (RS.CF) — This configuration ap-

plies to several machine control types (Configuration

UNIT

C.TYP = 1,2,3, and 5).

• 0 = NO RESET

No supply air reset is in effect

• 1 = SPT RESET

Space temperature will be used as the reset control variable

along with both RTIO and LIMT in the calculation of the

final amount of reset to be applied (Inputs

RSET

SA.S.R).

• 2 = RAT RESET

Return-air temperature will be used as the reset control vari-

able along with both RTIO and LIMT in the calculation of

the final amount of reset to be applied (Inputs

RSET

SA.S.R).

• 3 = 3RD PARTY RESET

The reset value is determined by a 4 to 20 mA third party

input. An input of 4 mA would correspond to 0º F reset. An

input of 20 mA would correspond to 20º F reset. Configur-

ing the control for this option will cause RES.S to become

enabled automatically with the CEM board. To avoid

alarms make sure the CEM board and third party input are

connected first before enabling this option.

Reset Ratio (RTIO) — This configuration is used when

RS.CF is set to 1 or 2. For every degree that the controlling

temperature (space/return) falls below the occupied cooling set

point (OCSP), the calculated value of the supply air reset will

rise by the number of degrees as specified by this parameter.
Reset Limit (LIMT) — This configuration is used when

RS.CF is set to 1 or 2. This configuration places a clamp on the

amount of supply air reset that can be applied.
EDT 4-20 mA Reset Input (RES.S) — This configuration is

automatically enabled when Configuration

EDT.R

RS.CF is set to 3 (third party reset).
COOLING CONFIGURATION — Relevant configurations for

mechanical cooling are located at the local display under

Configuration

COOL. See Table 47.

Table 45 — Setpoints

Table 46 — Supply Air Reset Configuration

ITEM

EXPANSION

RANGE

CCN

POINT

DEFAULTS

UNIT

UNIT CONFIGURATION

SIZE

Unit Size (20-60)

20-60

UNITSIZE

*

RFG.T

REFRIG

0-1

REFRIG_T

*

CND.T

CND HX TYP

0-1

COILTYPE

*

ITEM

EXPANSION

RANGE

UNITS

CCN POINT

DEFAULT

OHSP

Occupied Heat Setpoint

40-99

dF

OHSP

68

OCSP

Occupied Cool Setpoint

40-99

dF

OCSP

75

UHSP

Unoccupied Heat Setpoint

40-99

dF

UHSP

55

UCSP

Unoccupied Cool Setpoint

40-99

dF

UCSP

90

GAP

Heat-Cool Setpoint Gap

2-10

^F

HCSP_GAP

5

V.C.ON

VAV Occ. Cool On Delta

0-25

^F

VAVOCON

3.5

V.C.OF

VAV Occ. Cool Off Delta

1-25

^F

VAVOCOFF

2

SASP

Supply Air Setpoint

45-75

dF

SASP

55

SA.HI

Supply Air Setpoint Hi

45-75

dF

SASP_HI

55

SA.LO

Supply Air Setpoint Lo

45-75

dF

SASP_LO

60

SA.HT

Heating Supply Air Setpt

90-145

dF

SASPHEAT

85

T.PRG

Tempering Purge SASP

–20-80

dF

TEMPPURG

50

T.CL

Tempering in Cool SASP

5-75

dF

TEMPCOOL

5

T.V.OC

Tempering Vent Occ SASP

–20-80

dF

TEMPVOCC

65

T.V.UN

Tempering Vent Unocc. SASP

–20-80

dF

TEMPVUNC

50

ITEM

EXPANSION

RANGE

UNITS

CCN POINT

DEFAULT

EDT.R

EVAP.DISCHRGE TEMP RESET

RS.CF

EDT Reset Configuration

0 - 3

EDRSTCFG

0

RTIO

Reset Ratio

0 - 10

RTIO

2

LIMT

Reset Limit

0 - 20

^F

LIMT

10

RES.S

EDT 4-20 ma Reset Input

Enable/Disable

EDTRSENS

Disable