724-746-5500 | blackbox.com
724-746-5500 | blackbox.com
Page 25
Chapter 2: Installation
2.7 Chilled Water (CW) Cooling
The system uses a chilled water source to provide coolant to the cooling coil in the A/C unit. When the hot aisle air temperature
rises to the CW cut-in setpoint plus dead band, the controller opens the modulating CW control valve proportionally to the
demand for cooling (see Figure 2-7).
2.7.1 Piping Connections
CAUTION
The cooling coil (and associated piping circuits) are pressurized (up to 100 psi) and sealed when they leave the factory. Before
installing the interconnecting piping, release the pressure via an available stem valve or Schrader valve prior to uncapping the
pipes
.
Supply and return lines are routed to either the top or bottom of the cabinet as specified when the Cold Row system is ordered
(see Figures 2-8 and 2-9). On units that are piped from the top, the chilled water supply and return connections are made outside
the cabinet. On units that are piped from the bottom, the chilled water supply and return connections are made inside the
cabinet.
Pipe connections are threaded NPT connections. The pipes are labeled i.e.: “Supply,” “Return.” When making the connections, a
Teflon
®
tape thread sealant is recommended to minimize internal fouling of the piping.
Field piping is not necessarily the same size as the unit’s pipe connections. Piping should be sized to match the system pressure
drop and flow capacity, and may require reducing fittings to match the connection size on the air conditioner. An air vent and
several Schrader valves are installed in the precision A/C unit piping. We recommend providing manual shut-off valves for both
the supply and return fluid for isolating the unit when performing routine maintenance or repairs. Refer to the piping diagram
supplied with your unit.
NOTE: Install a 60-mesh strainer in the supply pipe. Make sure the strainer is readily accessible for servicing or replacement.
Figure 2-7. Typical CW piping diagram.