Piping connections
After the unit is leveled (and wedged in place for optional spring isolators) the piping connections
may be made: chilled water, condenser water, and refrigerant relief. The piping must be arranged
with offsets for flexibility, and adequately supported and braced independently of the unit to avoid
strain on the unit and vibration transmission. Hangers must allow for alignment of pipe. Isolators
(by others) in the piping and hangers are highly desirable, and may be required by specifications, in
order to effectively utilize the vibration isolation characteristics of the vibration isolation mounts of
the unit.
Check for piping alignment
Upon completion of piping, a connection in each line as close to the unit as possible should be
opened, by removing the flange bolts or coupling and checked for piping alignment. If any of the
bolts are bound in their holes, or if the connection springs out of alignment, the misalignment must
be corrected by properly supporting the piping or by applying heat to anneal the pipe.
Note: If the piping is annealed to relieve stress, the inside of the pipe must be cleaned of scale
before it is finally bolted in place.
Evaporator and condenser water piping
The evaporator and condenser liquid heads of chiller have nozzles which are grooved, suitable
for welding 150 psig DWP flanges or the use of Victaulic couplings. Factory mounted flanges are
optional.
The nozzles and water pass arrangements are furnished in accordance with the job requirements
(see product drawings furnished with the job). Standard units are designed for 150 psig DWP on
the water side. If job requirements are for greater than 150 psig DWP, check the unit data plate
before applying pressure to evaporator or condenser to determine if the chiller has provisions for
the required DWP.
Inlet and outlet connections are identified by labels placed adjacent to each nozzle.
Chilled water
Foreign objects which could lodge in, or block flow through, the evaporator and condenser tubes
must be kept out of the water circuit. All water piping must be cleaned or flushed before being
connected to the chiller pumps, or other equipment.
Permanent strainers
Permanent strainers are supplied by others and are required in both the evaporator and condenser
water circuits to protect the chiller as well as the pumps, tower spray nozzles, chilled water coils and
controls, etc. The strainer must be installed in the entering chilled water line, directly upstream of
the chiller.
Water piping circuits should be arranged so that the pumps discharge through the chiller, and
should be controlled as necessary to maintain essentially constant chilled and condenser water
flows through the unit at all load conditions.
If pumps discharge through the chiller, the strainer may be located upstream from pumps to
protect both pump and chiller. (Piping between strainer, pump and chiller must be very carefully
cleaned before start-up.) If pumps are remotely installed from chiller, strainers should be located
directly upstream of the chiller.
Centrifugal Liquid Chillers38
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