WaterFurnace Series NXW - Manual (Page 28)

28
ENVISION 2 NKW 50Hz REVERSIBLE CHILLER INSTALLATION MANUAL
Reference Calculations
Verify the following:
• High voltage is correct and matches nameplate
• Fuses, breakers and wire size are correct
• Low voltage wiring is complete
• Piping is complete and the water system has been cleaned
and flushed
• Air is purged from closed loop system
• Isolation valves are open and water control valves or loop
pumps are wired
• Service/access panels are in place
• Transformer has been switched to lower voltage tap if
needed (380/420 volt units only)
• Unit controls are in “off” position
• Flow switches are installed and ready or wires are jumpered
• Freeze detection setpoints have been set in the
microprocessor
WARNING: Verify ALL water controls are open and
allow water flow PRIOR to engaging the compressor.
Failure to do so can result in freezing the heat
exchanger or water lines causing permanent damage
to the unit.
Unit Startup
Startup Steps
• Set aquastat control above cooling setpoint.
• Set aquastat control in cooling mode.
• Slowly reduce the control setting until both the compressor
and water control valve/loop pumps are activated. Verify
that the compressor is on and that the water flow rate
is correct by measuring pressure drop through the heat
exchanger and comparing to the Pressure Drop table (page
32). Check for correct rotation of scroll compressors. Switch
any two power leads at the L1, L2, and L3 line voltage
termination block if incorrect.
• Perform a cooling capacity test by multiplying L/S x T x 4.1
(antifreeze/water). Use 4.2 for 100% water. Check capacity
against catalog data at same conditions.
• Set control to “OFF” position.
• Leave unit “OFF” for approximately five (5) minutes to allow
pressure to equalize.
• Adjust control below heating setpoint.
• Set control in “HEAT” position mode.
• Slowly increase the control setting until both compressor
and water control valve/loop pumps are activated. The
reversing valve should be heard changing over.
• Perform a heating capacity test by multiplying L/S x T x 4.1
(antifreeze/water). Use 4.2 for 100% water. Check capacity
against catalog data at same conditions.
• Check for vibrations, noise and water leaks.
• Set system to maintain desired setpoint.
• Instruct the owner/operator of correct control and system
operation.
HE
L/S x 4.2*
Heating Calculations: Cooling Calculations:
LWT = EWT +
HR
L/S x 4.2*
LWT = EWT -
NOTE: * When using water. Use 4.1 for 15% methanol/water or Environol solution.
Legend
ABBREVIATIONS AND DEFINITIONS:
COP = coefficient of performance
EER = cooling energy efficiency (TC/kW)
ELT = entering load fluid temperature
EST = entering source fluid temperature to heat pump
FLA = full load amps
FtHd = pressure drop in feet of head
gpm = US gallon per minute
HC = heating capacity in kW
HE = heat of extraction in kW
HR = heat rejected in kW
kPa = kilopascal
kW = kilowatt
L/s = liters per second
LLT = leaving load fluid temperature from heat pump
LRA = locked rotor amps (starting current)
LST = leaving source fluid temperature from heat pump
LWPD = load heat exchanger water pressure drop
MCC = maximum continuous current
PD = pressure drop
psi = pressure drop in pounds per square inch
P/T = Pressure/Temperature
RLA = run load amps
TC = total cooling capacity in kW
W = Watt
CONVERSIONS:
x°F = (x - 32)/1.8°C
1 bar = 100 kPa
1 gpm = 0.0631 L/s
1 US Gallon = 3.785412 L
1 Btu/h = 0.29037 W