Application Note

2 Fluke Corporation What’s shakin’ with your HVAC system?
epoxy one of the metal mount-
ing pads that come with the 810
onto the piece of machinery and
attach the sensor to the pad.
The second method provides the
810 with higher quality data,
but the data collection takes a
little longer. It’s the preferred
method for attaching the sensor
to equipment that you plan to
test regularly because once you
have a pad attached, you can
quickly attach the sensor in the
exact same place the next time,
making the process as quick,
consistent, and accurate as
possible.
Since this was our first
experience using the Fluke 810,
we decided to use the sensor’s
magnetic mount so we could get
some readings without delay.
The graphical display on the
Fluke 810 showed us the two
places where we should attach
the sensor to the pump, which
we did. After the sensor was
attached, it took less than a
minute to take a measurement.
That was it! The Fluke 810’s
onboard diagnostics indicated
on the color display that the
pump bearings had high wear
and recommended that we
replace them. Since we were
testing the equipment late at
night during the minimum usage
period (2 AM!), we scheduled
the pump repair for the next
day. When it was time for the
repair, the chilled water system
was run on the backup pump
while the bearings on the main
pump were changed. The repair
was a routine bearing replace-
ment and went smoothly, which
is exactly the kind of repair
you want. If the primary pump
had gone down, it might have
caused the entire chiller plant
to shut down, which could have
caused overheating computers
in the data center to shut down
and the operating rooms to lose
their cooling, which could be
life-threatening.
Chiller commissioning
During my visit, the hospital was
in the process of adding a new
1,250-ton centrifugal chiller
to its chiller rotation. When a
new machine is being brought
online, it’s the ideal time to take
baseline vibration measurements
that you can compare against
measurements that you take in
the future. Getting good baseline
measurements like this for the
owner’s records is an important
step when setting up a centrifu-
gal chiller control system.
I should mention that although
we used the 810 Vibration
Tester to take baseline vibration
measurements, the 810 does not
require baseline measurements
to evaluate a piece of machinery.
Instead, the 810 makes a diag-
nosis by comparing the vibration
measurements that you take
against a “synthetic baseline”
of vibration information for a
machine similar to the one that
you are testing. This synthetic
baseline is part of the 810’s
onboard “expert system” that
was developed by Fluke and
a partner firm who developed
its vibration expertise during
many years of vibration analy-
sis of industrial and military
equipment.
Since we knew that we would
be taking vibration readings
on the new chiller again, we
decided not to use the sen-
sor’s magnetic mount this time
and instead to epoxy four of
the mounting pads included
with the 810 onto the chiller
in the locations indicated in
the 810’s manual. After we
entered the required informa-
tion (horsepower from the
motor nameplate, RPM, use of a
variable speed drive, etc.), we
attached the vibration sensor
and took our readings. The 810
indicated that the new chiller
was operating perfectly! Later
we used the 810’s USB port to
transfer our vibration readings
from the 810 to a computer for
storage.
Air conditioning and cooling systems
• Centrifugal chillers
• Reciprocating chillers
• Chilled water pumps
• Condenser water pumps
• Cooling tower fans
• Fans and pumps on variable speed systems
Air handlers
• Supply fan motors
• Return fan motors
• Fan motors on variable speed systems
Heating systems
• Hot water pumps
• Condensate pumps
• Makeup water pumps
• Pumps on variable speed
systems
Product refrigeration
• Refrigerant pumps
• Screw chillers
• Motors on variable speed
systems
Common HVAC applications for vibration testers