53
Table 32 — Run Status Cool Display
Pull Down Cap Override (
PULL) — If the error from set
point is above 4F, and the rate of change is less than –1F 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
7.5F of change to EDT. If stages could reliably be cycled at
very fast rates, the set point 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 set point.
Humidi-MiZer® Capacity
(CAPC) — This variable repre-
sents the total reheat capacity currently in use during a Humidi-
MiZer mode. A value of 100% indicates that all of the dis-
charge gas is being bypassed around the condenser and into the
Humidi-MiZer dehumidification/reheat coil (maximum re-
heat). A value of 0% indicates that all of the flow is going
through the condenser before entering the Humidi-MiZer de-
humidification/reheat coil (dehum/subcooling mode).
Condenser EXV Position
(C.EXV) — This variable repre-
sents the position of the condenser EXV (percent open).
Bypass EXV Position
(B.EXV) — This variable represents
the position of the bypass EXV (percent open).
Humidi-MiZer 3-Way Valve
(RHV) — This variable repre-
sents the position of the 3-way valve used to switch the unit
into and out of a Humidi-MiZer mode. A value of 0 indicates
that the unit is in a standard cooling mode. A value of 1 indi-
cates that the unit has energized the 3-way valve and entered
into a Humidi-MiZer mode.
Cooling Control Point
(C.CPT) — Displays the current cool-
ing control point (a target value for air temperature leaving the
evaporator coil location). During a Humidi-MiZer mode, this
variable will take on the value of the dehumidify cool set point
(Configuration
DEHU
D.C.SP). Compressors will stage
up or down to meet this temperature.
Evaporator Discharge Temperature
(EDT) — Displays the
temperature measured between the evaporator coils and the
Humidi-MiZer dehumidification/reheat coil. Units configured
with Humidi-MiZer system have a thermistor grid installed be-
tween these two coils to provide the measurement. This tem-
perature can also be read at Temperatures
AIR.T
CCT.
Heating Control Point
(H.CPT) — Displays the current heat-
ing control point for Humidi-MiZer system. During a Reheat
mode, this temperature will be either an offset subtracted from
return air temperature (D.V.RA) or the Vent Reheat Set Point
(D.V.HT). During a Dehumidification mode, this temperature
will take on the value of the original cooling control point so
that the supply air is reheated just enough to meet the sensible
demand in the space. The Humidi-Mizer modulating valves
will adjust to meet this temperature set point.
Leaving Air Temperature
(LAT) — Displays the leaving air
temperature after the Humidi-MiZer reheat/dehumidification
coil.
ITEM EXPANSION RANGE UNITS CCN POINT WRITE STATUS
COOL COOLING INFORMATION
C.CAP Current Running Capacity % CAPTOTAL
CUR.S Current Cool Stage COOL_STG
REQ.S Requested Cool Stage CL_STAGE
MAX.S Maximum Cool Stages CLMAXSTG
DEM.L Active Demand Limit % DEM_LIM forcible
SUMZ COOL CAP. STAGE CONTROL
SMZ Capacity Load Factor -100 – +100 SMZ
ADD.R Next Stage EDT Decrease ^F ADDRISE
SUB.R Next Stage EDT Increase ^F SUBRISE
R.PCT Rise Per Percent Capacity RISE_PCT
Y.MIN Cap Deadband Subtracting Y_MINUS
Y.PLU Cap Deadband Adding Y_PLUS
Z.MIN Cap Threshold Subtracting Z_MINUS
Z.PLU Cap Threshold Adding Z_PLUS
H.TMP High Temp Cap Override HI_TEMP
L.TMP Low Temp Cap Override LOW_TEMP
PULL Pull Down Cap Override PULLDOWN
SLOW Slow Change Cap Override SLO_CHNG
HMZR HUMIDIMIZER
CAPC Humidimizer Capacity HMZRCAPC
C.EXV Condenser EXV Position COND_EXV
B.EXV Bypass EXV Position BYP_EXV
RHV Humidimizer 3-Way Valve HUM3WVAL
C.CPT Cooling Control Point COOLCPNT
EDT Evaporator Discharge Tmp EDT
H.CPT Heating Control Point HEATCPNT
LAT Leaving Air Temperature LAT
EXVS EXVS INFORMATION
A1.EX Circuit A EXV 1 Position XV1APOSP
A2.EX Circuit A EXV 2 Position XV2APOSP
B1.EX Circuit B EXV 1 Position XV1BPOSP
B2.EX Circuit B EXV 2 Position XV2BPOSP
SH.A1 Cir A EXV1 Superheat Tmp SH_A1
SH.A2 Cir A EXV2 Superheat Tmp SH_A2
SH.B1 Cir B EXV1 Superheat Tmp SH_B1
SH.B2 Cir B EXV2 Superheat Tmp SH_B2
CTRL EXVS CONTROL INFORMATION
C.SHS EXV Superheat Ctrl SP SH_SP_CT
C.FLS EXV SH Flooding Ctrl SP FL_SP_CT
C.EXP EXV PID Ctrl Prop. Gain EXV_PG_C
C.EXT EXV Ctrl Integrat. Time EXV_TI_C
C.EXM Cir Strt EXV Mn Ctrl Pos EXCSMP_C
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