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43
Table 47 — Run Status Cool Display
Current Running Capacity (C.CAP)
This variable represents the amount of capacity in percent that
is currently running.
Current Cool Stage (CUR.S)
This variable represents the cool stage currently running.
Maximum Cool Stages (MAX.S)
This variable is the maximum number of cooling stages the
control is configured for and capable of controlling.
Active Demand Limit (DEM.L)
If demand limit is active, this variable will represent the
amount of capacity that the control is currently limited to.
Capacity Load Factor (SMZ)
This factor builds up or down over time (–100 to +100) and is
used as the means of adding or subtracting a cooling stage
during run time. It is a normalized representation of the rela-
tionship between “Sum” and “Z.”
Next Stage EDT Decrease (ADD.R)
This variable represents (if adding a stage of cooling) how
much the temperature should drop in degrees depending on the
R.PCT
calculation and exactly how much additional capacity
is to be added.
ADD.R
=
R.PCT
*
(
C.CAP
— capacity after adding a cooling
stage)
For example: If
R.PCT
= 0.2 and the control would be adding
20% cooling capacity by taking the next step up, 0.2 times 20 =
4°F (
ADD.R
).
Next Stage EDT Increase (SUB.R)
This variable represents (if subtracting a stage of cooling)
how much the temperature should rise in degrees depending
on the
R.PCT
calculation and exactly how much capacity is
to be subtracted.
SUB.R
=
R.PCT
*
(
C.CAP
— capacity after subtracting a
cooling stage)
For Example: If
R.PCT
= 0.2 and the control would be subtract-
ing 30% capacity by taking the next step down, 0.2 times –30 =
–6°F (
SUB.R
).
Rise Per Percent Capacity (R.PCT)
This is a real time calculation that represents the amount of de-
grees of drop/rise across the evaporator coil versus percent of
current running capacity.
R.PCT
= (
MAT
–
EDT
)/
C.CAP
Cap Deadband Subtracting (Y.MIN)
This is a
control variable used for Low Temp Override
(
L.TMP
) and Slow Change Override (
SLOW
).
Y.MIN
=
-
SUB.R
*0.4375
Cap Deadband Adding (Y.PLU)
This is a control variable used for High Temp Override
(
H.TMP
) and Slow Change Override (
SLOW
).
Y.PLU
=
-
ADD.R
*0.4375
Cap Threshold Subtracting (Z.MIN)
This parameter is used in the calculation of SumZ and is calcu-
lated 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 SumZ and is calcu-
lated as follows:
Z.PLU
=
Configuration
COOL
Z.GN
* (10 + (4*
(
-
ADD.R
))) * 0.6
High Temp Cap Override (H.TMP)
If stages of mechanical 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 per minute, 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 per minute, then a mechanical stage
will be removed every 30 seconds. This override is intended to
quickly react to situations where the load is rapidly reduced.
Pull Down Cap Override (PULL)
If the error from setpoint 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
ITEM
EXPANSION
RANGE
UNITS
CCN POINT
WRITE STATUS
COOL
COOLING INFORMATION
C.CAP
Current Running Capacity
%
CAPTOTAL
CUR.S
Current Cool Stage
COOL_STG
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
Summary of Contents for WEATHERMAKER 48A2020
Page 112: ...112 Fig 20 Typical Main Control Box Wiring Schematic 48 50A Units ...
Page 113: ...113 Fig 21 Typical Auxiliary Control Box Wiring Schematic ...
Page 114: ...114 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown ...
Page 115: ...115 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown TO NEXT PAGE ...
Page 116: ...116 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont ...
Page 117: ...117 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown ...
Page 118: ...118 Fig 25 Typical Controls Option Wiring Schematic SW1 SW2 OR DEHUMIDIFY SWITCH ...
Page 119: ...119 Fig 26 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown ...
Page 120: ...120 Fig 27 Typical Power Schematic of Greenspeed Low Ambient Option 48 50A 060 Unit Shown ...
Page 121: ...121 Fig 28 Typical Small Chassis Component Location Size 020 035 Units ...
Page 122: ...122 Fig 29 Typical Large Chassis Component Locations Size 040 060 Units ...
Page 185: ...185 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716 ...