CDHF-SVX01N-EN
81
Figure 64.
Sequence of operation: ice making: stopped to ice to ice building complete
Command Ice Making via:
1. Front Panel OD (On)
2. Tracer (On)
3. External Input (Close/Short)
Evaporator Entering
Water Temperature
Falls Below the
Ice Termination
Setpoint
Remove All Ice Making Commands Via:
1. Front Panel OD (Auto)
2. Tracer (Auto)
3. External Input (Open)
Evaporator Entering Water Temperature
Rises Above the Ice Termination Setpoint
Auto
(Waiting
for a Need
to Cool)
Auto
(Waiting
to Start)
Auto
(Starting
Compressor)
Running
(Ice Building)
Prepare Shutdown
(Ice Building Complete)
Shutting Down
(Ice Building
Complete)
Run Inhibit
(Ice Building
Complete)
Auto
(Waiting
for a Need
to Cool)
Close IGV
(0 to 50 seconds)
Postlube
(3 minutes)
Ignore Evaporator
Pump Off Delay Time
for Ice Building
Head Relief Request Relay Delay
(1 to 60 minutes)
Open IGV at Max Rate/
Max AFD Frequency
Ignore Softloading and
Set CLS to 100%
Energize Ice
Building Relay
Close IGV/Min AFD
Frequency
De-Energize
Ice Building Relay
Energize Head Relief
Request Relay
De-Energize
Condenser
Water Pump Relay
De-Energize Head
Relief Request Relay
De-Energize
Compressor
De-Energize Oil Pump
De-Energize Evaporator
Water Pump Relay
Enforce All Limits and Running Mode Diagnostics
Confirm No Compressor Counts
Within 8 seconds
Hot Water Control
Occasionally, CenTraVac™ chillers are selected to
provide heating as a primary mission. With hot water
temperature control, the chiller can be used as a
heating source or cooling source. This feature provides
greater application flexibility. In this case, the operator
selects a hot water temperature and the chiller capacity
is modulated to maintain the hot water setpoint.
Heating is the primary mission and cooling is a waste
product or is a secondary mission. This type of
operation requires an endless source of evaporator
load (heat), such as well or lake water. The chiller has
only one condenser.
N
No
otte
e:: Hot Water Temperature Control mode does NOT
convert the chiller to a heat pump. Heat pump
refers to the capability to change from a cooling-
driven application to a heating-driven application
by changing the refrigerant path on the chiller.
This is impractical for centrifugal chillers as it
would be much easier to switch over the water
side.
This is NOT heat recovery. Although this feature could
be used to recover heat in some form, a heat recovery
unit has a second heat exchanger on the condenser
side.
The Tracer® AdaptiView™ provides the Hot Water
Temperature Control mode as standard. The leaving
condenser water temperature is controlled to a hot
water setpoint between 80°F and 140°F (26.7°C and
60.0°C). The leaving evaporator water temperature is
left to drift to satisfy the heating load of the condenser.
In this application, the evaporator is normally piped
into a lake, well, or other source of constant
temperature water for the purpose of extracting heat.
In Hot Water Temperature Control mode, all the limit
modes and diagnostics operate as in normal cooling
with one exception: the leaving condenser water
temperature sensor is an MMR diagnostic when in Hot
Water Temperature Control mode. (It is an
informational warning in the Normal Cooling mode.)
In the Hot Water Temperature Control mode, the
differential-to-start and differential-to-stop setpoints
are used with respect to the hot water setpoint instead
of with the chilled water setpoint. The control panel
provides a separate entry at the Tracer® AdaptiView™
to set the hot water setpoint; Tracer® AdaptiView™ is
also able to set the hot water setpoint. In the Hot Water
mode, the external chilled water setpoint is the external
hot water setpoint; that is, a single analog input is
shared at the 1A16-J2-5 to 6 (ground).
An external binary input to select external Hot Water
Control mode is on the EXOP OPTIONAL module 1A18
Содержание CenTraVac CDHF Series
Страница 103: ...CDHF SVX01N EN 103 N No ot te es s ...
