WaterFurnace Series NXW - Manual (Page 10)

10
ENVISION 2 NKW 50Hz REVERSIBLE CHILLER INSTALLATION MANUAL
General
System piping should be kept as simple as possible to
minimize the pressure drop, but hand valves should be field
installed to facilitate unit servicing. The piping installation
should provide service personnel with the ability to measure
and/or monitor water temperatures and pressures.
Source and load fluid connections are provided with 2-inch
[50.8mm] Victaulic grooved nipples (see Figure 4). Each
nipple will also have a PT port installed for test and balance
purposes. It will be the installing contractor’s responsibility
to adequately support incoming piping to avoid damage to
the unit’s piping or heat exchangers. The water lines should
be routed so as not to interfere with access to the unit.
For any installation where the transmission of vibration
through the piping connections could cause unacceptable
noise levels in occupied spaces it is important to provide
adequate vibration damping.
NOTE: Units are factory run-tested using propylene
glycol. Prior to connecting piping to unit, thoroughly flush
heat exchangers.
Before final connection to the unit, the supply and return
hose kits must be connected to each other, bypassing
the unit, and the system flushed to remove dirt, piping
chips and other foreign material. Normally, a combination
balancing and close-off (ball) valve is installed at the return,
and a rated gate or ball valve is installed at the supply. The
return valve can be adjusted to obtain the proper water
flow. The valves allow the unit to be removed for servicing.
The proper water flow must be delivered to each unit
whenever the unit heats or cools. The proper flow rate
cannot be accurately set without measuring the water
pressure drop through the refrigerant-to-water heat
exchanger. A 3 GPM flow rate per ton [0.054 LPS per kW]
of cooling capacity (2.25 GPM per ton [0.0404 LPS per
kW] minimum) is required.
NOTE: The placement and connection of the water
circulating pump(s) must be taken into consideration prior
to designing the final water piping systems.
Field Connected Water Piping
CAUTION: Remove the plastic protective caps in the ends of each of the four water pipes on the heat
exchangers prior to piping connection. Failure to remove the caps will result in serious damage and could void
the warranty.
Closed Loop Tower/Boiler Systems
The water loop is usually maintained between 60°F [15.5°C]
and 90°F [32.2°C] for proper heating and cooling operation.
This is accomplished with a cooling tower and a boiler.
To reject excess heat from the condenser water loop, the
use of a closed-circuit evaporative cooler or an open type
cooling tower with a secondary heat exchanger between
the tower and the condenser water loop is recommended.
If an open type cooling tower is used without a secondary
heat exchanger, continuous chemical treatment and filtering
of the water must be performed to ensure the water is free
from damaging materials.
CAUTION: Water piping exposed to outside
temperature may be subject to freezing.
Open Loop Well Water Systems
Installation of an open loop system is not recommended
without using a secondary heat exchanger unless water
quality guidelines are met.
Earth Coupled Systems
All supply and return water piping should be insulated to
prevent excess condensation from forming on the water
lines. Ensure pumping system is capable of providing
adequate flow rate at the system pressure drop, 3.0 GPM
per ton [0.054 LPS per kW] (source side) is recommended.
Antifreeze in the loop is strongly recommended.