IBM 9008-22L Site And Hardware Planning page 77

• Be adjustable only with the use of a tool.
• Have a discharge opening that is directed so that discharged water or fluid does not create a
hazard or be directed toward any person.
• Be of adequate discharge capacity to ensure that the maximum working pressure is not
exceeded.
• Be installed without a shutoff valve between the overpressure safety device and the protected
device.
Read the following guidelines before you design the installation:
• A method for monitoring and setting the total flow rate that is delivered to all of the heat exchangers is
required. This can be a discrete flowmeter that is built into the flow loop or a flowmeter within the
secondary loop of the coolant distribution unit (CDU).
• After you set the total flow rate for all of the heat exchangers by using a flowmeter, it is important to
design the plumbing so that it provides the flow rate that you want for each heat exchanger and
provides a way to verify the flow rate. Other methods, such as inline or external flowmeters, can provide
a more accurate method for setting the flow rate through the individual shutoff valves.
Manifolds and piping:
Manifolds that accept large-diameter feed pipes from a pump unit are the preferred method for
splitting the flow of water to smaller-diameter pipes or hoses that are routed to individual heat
exchangers. Manifolds must be constructed of materials that are compatible with the pump unit and
related piping. The manifolds must provide enough connection points to allow a matching number of
supply and return lines to be attached, and the manifolds must match the capacity rating of the
pumps and the loop heat exchanger (between the secondary cooling loop and the building chilled-
water source). Anchor or restrain all manifolds to provide the required support to avoid movement
when quick-connect couplings are connected to the manifolds.
Example of manifold supply pipe sizes:
• Use a 50.8 mm (2 in.) or larger supply pipe to provide the correct flow to three 19 mm (0.75 in.)
supply hoses, with a 100 kW coolant distribution unit (CDU).
• Use a 63.5 mm (2.50 in.) or larger supply pipe to provide the correct flow to four 19 mm (0.75 in.)
supply hoses, with a 120 kW CDU.
• Use an 88.9 mm (3.50 in.) or larger supply pipe to provide the correct flow to nine 19 mm (0.75 in.)
supply hoses, with a 300 kW CDU.
To stop the flow of water in individual legs of multiple circuit loops, install shutoff valves for each
supply and return line. This provides a way to service or replace an individual heat exchanger without
affecting the operation of other heat exchangers in the loop.
To ensure that water specifications are being met and that the optimum heat removal is taking place,
use temperature and flow metering (monitoring) in secondary loops.
Anchor or restrain all manifolds and pipes to provide the required support and to avoid movement
when quick-connect couplings are being attached to the manifolds.
Flexible hoses and connections to manifolds and heat exchangers:
Pipe and hose configurations can vary. You can determine the best configuration for your installation
by analyzing the needs of your facilities, or a site preparation representative can provide this analysis.
Flexible hoses for the cold-water supply and warm water return are provided with the delivery of the
rear door heat exchanger (allowing needed movement for opening and closing the rack rear door). The
customer needs to supply a 2.54 cm (1 in.) female national pipe thread (NPT) fitting for each supply
and return hose connection to the facility. The IBM supplied hoses contain the quick connect fittings
to mate to the fittings on the rear door heat exchanger.
Use solid piping or tubing that has a minimum inner diameter of 19 mm (0.75 in.) and the fewest
possible joints between a manifold and a heat exchanger in each secondary loop.
Site and hardware planning 63