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

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Cap Threshold Subtracting ( Z.MIN ) — This parameter is
used in the calculation of SMZ and is calculated as follows:
Z.MIN = Configuration

COOL

Z.GN * (–10 + (4*
( – SUB.R ))) * 0.6
Cap Threshold Adding ( Z.PLU ) — This parameter is used in
the calculation of SMZ and is calculated as follows:
Z.PLU = Configuration

COOL

Z.GN * (10 + (4*
( – ADD.R ))) * 0.6
High Temp Cap Override ( H.TMP ) — If stages of mechani-
cal cooling are on and the error is greater than twice Y.PLU ,
and the rate of change of error is greater than 0.5

F, then a
stage of mechanical cooling will be added every 30 seconds.
This override is intended to react to situations where the load
rapidly increases.
Low Temp Cap Override (
L.TMP ) — If the error is less than
twice Y.MIN , and the rate of change of error is less than
–0.5

F, then a mechanical stage will be removed every 30 sec-
onds. This override is intended to quickly react to situations
where the load is rapidly reduced.
Pull Down Cap Override (
PULL ) — If the error from set-
point is above 4

F, and the rate of change is less than –1

F per
minute, then pulldown is in effect, and “SUM” is set to 0. This
keeps mechanical cooling stages from being added when the
error is very large, but there is no load in the space. Pulldown
for units is expected to rarely occur, but is included for the rare
situation when it is needed. Most likely pulldown will occur
when mechanical cooling first becomes available shortly after
the control goes into an occupied mode (after a warm unoccu-
pied mode).
Slow Change Cap Override ( SLOW ) — With a rooftop unit,
the design rise at 100% total unit capacity is generally around
30

F. For a unit with 4 stages, each stage represents about
7.5

F of change to EDT. If stages could reliably be cycled at
very fast rates, the setpoint could be maintained very precisely.
Since it is not desirable to cycle compressors more than 6 cy-
cles per hour, slow change override takes care of keeping the
PID under control when “relatively” close to setpoint.
MODE TRIP HELPER — The Mode Trip Helper table pro-
vides information on the unit modes and when the modes start
and stop. See Table 94. This information can be used to help
determine why the unit is in the current mode.
CCN/LINKAGE DISPLAY TABLE — The CCN/Linkage
display table provides information on unit linkage. See
Table 95.
COMPRESSOR RUN HOURS DISPLAY TABLE — The
Compressor Run Hours Display Table displays the number of
run time hours for each compressor. See Table 96.
COMPRESSOR STARTS DISPLAY TABLE — The Com-
pressor Starts Display Table displays the number of starts for
each compressor. See Table 97.
TIME GUARD DISPLAY TABLE — The Time Guard Dis-
play Table delay time for each compressor and heat relay. See
Table 98.
SOFTWARE VERSION NUMBERS DISPLAY TABLE —
The Software Version Numbers Display Table displays the
software version numbers of the unit boards and devices. See
Table 99.
Table 91 — Auto View of Run Status Display Table
Table 92 — Economizer Run Status Display Table
ITEM EXPANSION RANGE UNITS POINT WRITE STATUS
VIEW AUTO VIEW OF RUN STATUS
HVAC ascii string spelling out the hvac modes string
OCC Occupied ? YES/NO OCCUPIED forcible
MAT Mixed Air Temperature dF MAT
EDT Evaporator Discharge Tmp dF EDT
LAT Leaving Air Temperature dF LAT
EC.C.P Economizer Control Point dF ECONCPNT
ECN.P Economizer Act.Curr.Pos. 0-100 % ECONOPOS
CL.C.P Cooling Control Point dF COOLCPNT
C.CAP Current Running Capacity CAPTOTAL
HT.C.P Heating Control Point dF HEATCPNT
HT.ST Requested Heat Stage HT_STAGE
H.MAX Maximum Heat Stages HTMAXSTG
ITEM EXPANSION RANGE UNITS POINT WRITE STATUS
ECON ECONOMIZER RUN STATUS
ECN.P Economizer Act.Curr.Pos. 0-100 % ECONOPOS
ECN.C Economizer Act.Cmd.Pos. 0-100 % ECONOCMD forcible
ACTV Economizer Active ? YES/NO ECACTIVE
DISA ECON DISABLING CONDITIONS
UNAV Econ Act. Unavailable? YES/NO ECONUNAV
R.EC.D Remote Econ. Disabled? YES/NO ECONDISA
DBC DBC - OAT Lockout? YES/NO DBC_STAT
DEW DEW - OA Dewpt.Lockout? YES/NO DEW_STAT
DDBC DDBD- OAT > RAT Lockout? YES/NO DDBCSTAT
OAEC OAEC- OA Enth Lockout? YES/NO OAECSTAT
DEC DEC - Diff.Enth.Lockout? YES/NO DEC_STAT
EDT EDT Sensor Bad? YES/NO EDT_STAT
OAT OAT Sensor Bad ? YES/NO OAT_STAT
FORC Economizer Forced ? YES/NO ECONFORC
SFON Supply Fan Not On 30s ? YES/NO SFONSTAT
CLOF Cool Mode Not In Effect? YES/NO COOL_OFF
OAQL OAQ Lockout in Effect ? YES/NO OAQLOCKD
HELD Econ Recovery Hold Off? YES/NO ECONHELD
DH.DS Dehumid Desabled Econ? YES/NO DHDISABL
O.AIR OUTSIDE AIR INFORMATION
OAT Outside Air Temperature dF OAT forcible
OA.RH Outside Air Rel. Humidity % OARH forcible
OA.E Outside Air Enthalpy OAE
OA.D.T OutsideAir Dewpoint Temp dF OADEWTMP