Carrier AquaEdge 19DV series, Управление, эксплуатация и устранение неисправностей

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The default screen indicates when the chilled water reset is ac-
tive. The control point Reset on the General Parameters screen
indicates the amount of reset.
To activate a reset type, access the Reset Configuration
(RESETCFG) screen and input all configuration informa-
tion for that reset type.
Reset Type 1: 4 to 20 mA Temperature Reset
Reset Type 1 is an automatic reset utilizing a 4 to 20 mA analog
input signal provided from any external sensor, controller, or
other device which is appropriately configured. For this type,
Degrees Reset At 20 mA is configured in the RESETCFG table.
Reset Type 2: Remote Temperature Reset
Reset Type 2 is an automatic water temperature reset based on
a remote temperature sensor input signal. This function can be
accessed by setting the following configurations:
1. Configure the remote temperature at which no reset occurs
( Remote temp

NO RESET ).
2. Configure the remote temperature at which full reset
occurs ( Remote temp

FULL RESET ).
3. Enter the amount of reset (Deg Reset Water DT Full).
Reset Type 3: Controlled Water Temp Delta Reset
Reset Type 3 is an automatic controlled water temperature re-
set based on heat exchanger temperature difference. This func-
tion can be accessed by setting the following configurations:
1. Configure the controlled water temperature delta T at which
no reset occurs ( Controlled Water DELTA T

NO
RESET ).
2. Configure the controlled water temperature delta T at
which full reset occurs ( Controlled Water DELTA T

FULL RESET) .
3. Enter the amount of reset (Deg Reset Water DT Full).
CAPACITY CONTROL
Capacity control provides chilled or condenser water tempera-
ture control by modulating the position of the inlet guide vane 1
and VFD speed for variable speed compressors.
For 19DV when increased capacity is needed, the control will
first try to increase IGV TARGET POSITION if it has not
reached the travel limit; if the travel limit has been reached, the
control increases VFD TARGET SPEED. If decreased capacity
is needed, the control first tries to decrease VFD TARGET
SPEED if it has not reached the minimum VFD speed; if the
minimum VFD speed has been reached, the control decreases
IGV TARGET POSITION instead. See Fig. 31.
From the compressor relay closed point to the end of ramp
loading, the VFD TARGET SPEED is the configured VFD
start-up speed. When the chiller is running normally, the capac-
ity control determines whether and how much to change VFD
TARGET SPEED. When the chiller is in the shut-down pro-
cess, VFD TARGET SPEED will be the minimum VFD speed.
NOTE: If the VFD option is set to NO VFD, or the compressor re-
lay is not closed, VFD TARGET SPEED will be 0.
The guide vane position is determined by the Capacity Control
function under normal conditions and other functions in abnor-
mal conditions, which include capacity inhibit request or capaci-
ty decrease request. The guide vane actuator is driven by com-
paring the guide vane target position and the actual position.
Guide vane position is limited to a value between zero and IGV
Travel Limit, which is configured from the Service Configura-
tion menu. When the chiller is shutting down or off, the guide
vane is always driven to zero during normal shutdown. Guide
Vane 2 is forced based on linear interpolation of set points based
on Guide Vane 1 position (see 19DV Configuration).
Fig. 31 — Guide Vane Position and VFD Speed
GUIDE VANE S AT MAX.
MODULATE VFD
GUIDE VANE S
VFD AT S TART-UP S PEED,
MODULATE GUIDE VANE S
VFD
S TARTUP:
VFD TO S TART-UP S PEED,
GUIDE VANE S CLO S ED
MAX.
S TART
MIN.
VFD % S PEED
0 TRAVEL LIMIT
100
GUIDE VANE S % PO S ITION