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Fig. 45 — Trending Screen Set-Up Page
Fig. 46 — Trending Screen Display Page
Hydraulic Option
WATER FLOW MEASUREMENT
The PIC6 controller provides the function of measuring water
flow rate.
Equipped with a field installed flow meter, it can compute the
water flow rate from the input signal sent from the evaporator/
condenser water flow sensor (4 to 20 mA) to the IOB (see
Fig. 4, IOB4 wiring schematic).
Step 1: Set
Factory Parameters
IOB4 Option
as “Yes.”
Step 2: Set
Option Configuration
Water Flow Measure-
ment
as “1 = Flow Meter,” and enter the corresponding value
of Water Flow at 4 mA and 20 mA.
Step 3: In “Hydraulic Status” menu, check evaporator/condenser
water flow rate value. (The flow rate value will be linear interpo-
lated by actual reading and configured water flow rate at 4 mA/
20 mA.)
Water flow can also be computed from water pressure sensors
or water pressure drop sensors (see IOB4 wiring schematic).
IOB4 Option must be Enabled and Water Flow Measurement
option configured as “2 = Water Pres. Difference” and the
evaporator/condenser pressure drop baseline and water flow
must be entered as inputs.
Equipped with a normally open flow switch, the evaporator/
condenser water flow can be directly indicate the flow status
(see IOB1 wiring schematic).
WATER PRESSURE DIFFERENCE MEASUREMENT
When entering and leaving water pressure transducers or 4 to
20 mA water pressure differential transducers are installed, the
PIC6 can compute or read the water pressure difference be-
tween entering and leaving water pressure, and thereby deter-
mine if the water is flowing. After the water pump is switched
on, if the water pressure difference reaches the threshold, the
water flow check is passed and the chiller can start. Otherwise
there will be an alarm shutdown.
Step 1: Set
Factory Parameters
IOB4 Option
as “Yes.”
Step 2: Set
Option Configuration
Water Pressure Option
as either “1 = Pres” or “2 = Pres.D” (4 to 20 mA signal). Note
that for Option 2 the Water Pres Drop @ 20 mA must also be
set in Option Configuration.
Step 3: In “Hydraulic Status” menu, check Condenser Water
Delta P, Condenser Water Flow, Evaporator Water Delta P,
Evaporator Water Flow.
MARINE OPTION(S)
A marine (shipboard) chiller has different requirements com-
pared with typical chillers.
NOTE: These options are not intended to be used for comfort
cooling applications.
Power Request
If
Factory Parameters
Power Request Option
is enabled,
when chiller is starting up, it will send power request signal and
alert 104 while verifying water flow. After it receives permission
to start feedback, the start-up will proceed. The power request
signal will remain active until the compressor is switched on. If
start feedback has not been received 5 minutes after power re-
quest is sent, or permission to start feedback is deactivated be-
fore compressor is switched on, the start-up process will termi-
nate and trigger an alarm. If
Factory Parameters
Cont Power
Request
option is enabled, the power request signal will remain
active after the compressor is switched on. Should the signal be
deactivated while the compressor is running, an alarm shutdown
will be triggered.
Evaporator Approach Calculation
If
Option Configuration
Evap App Calc Selection
is set to Sat
Temp, evaporator approach will be calculated from evaporator
leaving water temperature and evaporator saturated temperature.
If this option is set to Ref Temp, evaporator approach will be
calculated from evaporator leaving water temperature and
evaporator refrigerant temperature.
Free Cooling
If
Factory Parameters
Free Cooling Option
is enabled, any
one of the following will make the chiller start free cooling.
• Enable
General Parameters
Start Free Cooling
• In Network Mode, enable
General Parameters
Start
Free Cooling
from CCN, BACNet
1
, or Modbus
2
.
• Close Free Cooling Start Switch contact. (5TB terminals
65, 66) with field supplied relay.
When free cooling is in progress, the chiller will take these
actions:
• Switch on evaporator and condenser water pump
• Open head pressure valve to maximum opening position
• Open guide vanes to maximum opening position
• Activate free cooling mode output contact (24 VAC on
5TB terminal 67)
• Display Free Cooling mode on the homepage.
• Force liquid bypass valve open
• Fully open free cooling vent valve between evaporator and
condenser
Free cooling mode will only be activated when chiller is not
running. If the chiller is running, free cooling start request will
1. BACnet is a registered trademark of ASHRAE (American Society of
Heating, Refrigerating, and Air-Conditioning Engineers).
2. Modbus is a registered trademark of Schneider Electric.
