Carrier 48/50AJ Machine Dependent Configurations, Setpoints, Supply Air Reset Configuration

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

ITEM	EXPANSION	RANGE	CCN	DEFAULTS
			POINT
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	*

*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

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

Table 46 — Supply Air Reset Configuration

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

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