Fluke 810 Service Guide

What’s shakin’ with

your HVAC system?

Application Note

Senior HVAC technician Ron Auvil checks out a chiller, a
noisy pump, and a couple of shaky compressors with the
Fluke 810 Vibration Tester

The new Fluke 810 Vibration Tester
was designed to enable technicians
with no training in vibration measure­ment and analysis to test pumps,
motors, compressors, and other HVAC
equipment and get both diagnoses
and recommendations for required

action on the spot within just a few
minutes. I took an 810 with me on
recent visits to a couple of facilities
with critical HVAC applications to learn
how it works and to try it out under
real-world conditions.

Beating bad bearings

My first stop was a late-night
visit to the chilled water plant
of a local hospital. A reliable
supply of chilled water to cool
the hospital’s emergency rooms
and data center is a big priority
there, so they test the system
along with the emergency
backup generator every month.
Before we shut down the system
for testing, we did a walk­through and gave the primary
chilled water pumps and other
equipment a good visual inspec­tion. While we were doing
so, one of the hospital techni­cians told me that one of the
2,000-gallon-per-minute chilled
water pumps seemed to be run­ning a little loud. I agreed, but
although an experienced ear is
an important troubleshooting
tool, this symptom was trouble­some but not conclusive. This
seemed like a great opportunity
to try out the Fluke 810 for the
first time.

It took me about ten minutes
to read the 810’s instruction
manual and get set up. The
first thing the 810 prompted
me to do was to enter some
basic information about the
drive train setup, such as motor
horsepower, RPM, and pump
layout. I was able to get a lot of
this information from the motor
nameplate. To measure the run­ning speed (RPMs), I plugged in
the laser tachometer that comes
with the 810 and pointed it at
the motor shaft. It gave me a
reading of 1,711 RPM, which
was automatically entered into
the 810.

After I finished entering the
setup information, I attached the
810’s vibration sensor while the
hospital technician looked on
so he would be able to do it in
the future. There are two ways
that you can attach the 810’s
three-axis vibration sensor. The
first and easiest way is to use
the sensor’s powerful magnetic
mounting. The other way is to

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epoxy one of the metal mount­ing 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 replace­ment 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 centrifu­gal 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 diag­nosis 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 analy­sis 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 sen­sor’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 informa­tion (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.

Common HVAC applications for vibration testers

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

2 Fluke Corporation What’s shakin’ with your HVAC system?

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

A vibration tester even
an expert can love

One of my favorite sites to visit
is a large arena that is home to
an NBA team and both profes­sional and college hockey teams.
The site also regularly hosts ice
skating shows and competi­tions. Several large reciprocating
compressors are used to make
the ice for these events. (Inter­estingly, the ice used for hockey
is kept at a different tempera­ture than the ice used for figure
skating. The ice temperature for
both, however, is kept to tight
tolerances, and before an event
starts, compliance is verified by
officials using a Fluke infrared
thermometer.)

When we visited the rink,
its cooling system was being
checked in preparation for the
busy season ahead. As part of
the equipment overhaul and
checkout, we decided use the
Fluke 810 Vibration Tester to
perform a thorough vibration test
on the ice system reciprocating
compressors. Since I knew we
would want to check the equip­ment again in the future, we
epoxied the provided mounting
pads onto the proper locations
on the compressors.

We decided to check the pump
first. On pump startup, we used
the 810’s laser tachometer to
measure the motor RPMs and
enter the other required data
with the keypad, and then took
our vibration measurements.
Next we did the same for the
reciprocating compressors.

Although the Fluke 810
Vibration Tester was developed
for people with no vibration
measurement experience, it
also has features that people
with vibration expertise will

appreciate. For example, the
810 generates a graph of the
vibration spectra that you
can examine right on its color
screen. (You can also download
the vibration data from the 810
to a computer and examine it
with the included Viewer PC
software.) This enables vibra­tion consultants and others with
vibration expertise to evaluate
vibration data visually. Doing so,
we were able to see a truncated
waveform for the piston stroke
and top dead center timing at
the end of the stroke on one of
the compressors. Experience
indicated that this was caused
by some looseness in rod end
bearings. We repaired these and
then rechecked. All was well!

When we tested a second,
identical compressor, the 810
indicated some structural loose­ness. When we re-torqued the
hold-down bolts and rechecked
with the 810, the vibration prob­lem had disappeared.

By measuring and evaluat­ing the vibration data for these
two machines with the Fluke
810, we were able to detect and
correct problems that could have
caused real problems.

Something for everyone

You don’t have to be a pro
to appreciate the Fluke 810
Vibration Tester, because the
expertise is built into the device.
We were able to read the
manual, attach the sensor, enter
the required information, and
get understandable and useful
diagnostic information within
minutes of opening the box. By
just following the prompts that
appear on the screen you can
start saving thousands of dollars
in reduced downtime and emer­gency maintenance.

Fluke. Keeping your world
up and running.

Fluke Corporation

PO Box 9090, Everett, WA 98206 U.S.A.

Fluke Europe B.V.

PO Box 1186, 5602 BD
Eindhoven, The Netherlands

For more information call:

In the U.S.A. [phone] or
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Fax [phone]
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Fax [phone]
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Web access: http://www.fluke.com

©2010 Fluke Corporation.
Specifications subject to change without notice.
Printed in U.S.A. 10/2010 3941896B A-EN-N

Modification of this document is not permitted
without written permission from Fluke Corporation.

®

3 Fluke Corporation What’s shakin’ with your HVAC system?