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• 120°F to 140°F Condenser LWT: 430 to 560 psig
Suction pressure: Take at Schrader fitting
provided on the suction line. Normal suction
pressures are: • 42°F to 60°F LWT: 104 to
155 psig
• 15°F to 39°F LWT: 60 to 103 psig
Compressor Operational Noises
At low ambient startup: When the compressor
starts up under low ambient conditions, the initial
flow rate of the compressor is low. Under these
conditions, it is not unusual to hear the compressor
rattle until the suction pressure climbs and the flow
rate increases. These sounds are normal and do
NOT affect the operation or reliability of the
compressor.
Excessive Amp Draw
Excessive Amp Draw occurs either because the
compressor is operating at an abnormally high
condensing temperature OR because of low
voltage at the compressor motor.
Motor amp draw may also be excessive if the
compressor has internal mechanical damage. In
this situation, vibration and discolored oil can also
be observed.
Low Suctions
Continuous low suction pressures are most likely
caused by low evaporator load coupled with a
system anomaly such as low chilled water flow.
Note: Operation of the chiller with saturated
suction temperatures below freezing will cause
damage to the evaporator. If this occurs
immediately stop the machine, diagnose and
correct the problem.
Heat Exchanger Maintenance
When to Clean a Brazed Plate Heat Exchanger
(BPHE)
A temperature difference, less than specified,
indicates a sign of scaling because fouling of the
channel plate surface decreases the heat transfer.
Hence the inlet and outlet temperatures of the
BPHE should be measured continuously. Pressure
drops larger than specified indicate scaling since it
restricts the channel passage and thus increases
velocity. Make sure that readings follow water
flow rate corresponding to the specification, since
changes in flow rate effect temperatures and
pressure drops. By removing the scale build-ups,
the operating efficiencies of the equipment and
heat transfer surfaces are restored. Other benefits
from removing the scale are that it lowers the
pressure drops, reduces the power consumption
and extends the lifetime of the equipment.
How to Clean a Brazed Plate Heat Exchanger
(BPHE)
FWCD chiller BPHEs are cleaned quickly and
easily with Cleaning in Place (CIP), a method used
for the interior surfaces of closed systems, such as
pipes, vessels, process equipment, and filters. A
chemical fluid is circulated through the BPHE,
without the need for disassembly. The chemicals
dissolve or loosen deposits from process
equipment and piping, giving uniform removal
and lower overall operating costs. Following is a
general description of the system setup, the CIP
procedure, and the various cleaning fluids.
Cleaning in Place (CIP) Procedure
Start
1. Shut off relevant pumps
2. Shut off the primary side's valves
3. Shut off the secondary side's valves
4. Empty the BPHE
5. Wash it with water to remove loose
contamination
6. Connect the machine via inlet/outlet at
front or backside
7. Mix chemical and water according to
instructions such as for Scale 132 Copper
8. Heat the solution to 120-140F, make use of
primary side heat if possible
9. Pump the solution in the BPHE using the
lower opening to ventilate air. A flow rate
corresponding to 1.5 times the normal flow
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