United Technologies Carrier Weathermaker 48A2, Controls, Start-Up, Operation, Service, And Troubleshooting

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• 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
setpoint ( 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 36.
Capacity Threshold Adjust ( Z.GN ) — This configuration is
used for units using the “SumZ” algorithm for cooling capacity
control ( Configuration

UNIT

C.TYP = 1, 2, 3 or 5). The
configuration affects the cycling rate of the cooling stages by
raising or lowering the threshold that demand must rise above
in order to add or subtract a stage of cooling.
Normally this configuration should not require any tuning or
adjustment. If there is an application where the unit may be sig-
nificantly oversized and there are indications of high compres-
sor cycles, then the Capacity Threshold Adjust ( Z.GN ) can be
used to adjust the overall logic gain. Normally this is set to 1.0,
but it can be adjusted from 0.5 to 4.0. As the value of Z.GN is
increased, the cycling of cooling stages will be slowed.
Table 34 — Setpoints
Table 35 — Supply Air Reset Configuration
Table 36 — Cooling Configuration
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
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
COOL COOLING CONFIGURATION
Z.GN Capacity Threshold Adjst –10 - 10 Z_GAIN 1
MC.LO Compressor Lockout Temp –20 - 55 dF OATLCOMP 40
C.FOD Fan-Off Delay, Mech Cool 0-600 sec COOL_FOD 60
MLV Min. Load Valve (HGBP)? Yes/No MLV_SEL No
M.M. Motor Master Control ? Yes/No MOTRMAST No
MM.OF Motor Master Setpoint Offset –20 - 20 dF MMSPOFST –10
MM.RR Motor Master PD Run Rate 10-120 sec MM_RATE 10
MM.PG Motor Master Proportional Gain 0.0-5 MM_PG 1
MM.DG Motor Master Derivative Gain 0-5 MM_DG 0.3
MM.TI Motor Master Integration Time 0-50 MM_TI 30
DS.EN Enable Digital Scroll? Yes/No DIGCMPEN No
DS.MC DS Min Digital Capacity 25 - 100 % MINCAPDS 50
DS.AP Dig Scroll Adjust Delta 0 - 100 % DSADJPCT 100
DS.AD Dig Scroll Adjust Delay 15 - 60 sec DSADJDLY 20
DS.RP Dig Scroll Reduce Delta 0 - 100 % DSREDPCT 6
DS.RD Dig Scroll Reduce Delay 15 - 60 sec DSREDDLY 30
DS.RO Dig Scroll Reduction OAT 70 - 120 dF DSREDOAT 95
DS.MO Dig Scroll Max Only OAT 70 - 120 dF DSMAXOAT 105
HPSP Head Pressure Setpoint 80 - 150 dF HPSP 110
A1.EN Enable Compressor A1 Enable/Disable CMPA1ENA Enable
A2.EN Enable Compressor A2 Enable/Disable CMPA2ENA Enable
B1.EN Enable Compressor B1 Enable/Disable CMPB1ENA Enable
B2.EN Enable Compressor B2 Enable/Disable CMPB2ENA Enable
CS.A1 CSB A1 Feedback Alarm Enable/Disable CSB_A1EN Enable
CS.A2 CSB A2 Feedback Alarm Enable/Disable CSB_A2EN Enable
CS.B1 CSB B1 Feedback Alarm Enable/Disable CSB_B1EN Enable
CS.B2 CSB B2 Feedback Alarm Enable/Disable CSB_B2EN Enable
REV.R Rev. Rotation Verified? Yes/No REVR_VER No
H.SST Hi SST Alert Delay Time 5 - 30 min HSSTTIME 10