TSI Instruments Alnor Velometer 6000 Series User manual

®
A TSI Company
®
Velometer®
Series 6000
OWNER’S MANUAL

1
TABLE OF CONTENTS
Using the Velometer Safely 2
General Description 3
Meter 3
Range Selector 4
Pitot Probe 5
Lo-Flow Probe 5
Diffuser Probe 6
Static Pressure Probe 6
Preparation for Use 7
Diffuser Probe 7
Static Pressure Probe 8
Pitot Probe 9
Lo-Flow Probe 9
Operation 10
Procedure for Measuring Velocity with Lo-Flow Probe 10
Velocities at Suction Openings—Except Diffusers
or Grilles 10
At Grinding or Buffing Wheels 10
At Spray Booths 10
Velocities at Plating Tanks 10
Procedure for Measuring Diffuser, Register and Grille
Velocities with Diffuser Probe 11
Typical Diffuser Air Flow Measuring Procedure 11
Procedure for Measuring Static Pressure 13
Procedure for Air Flow Measurement in Ducts 13
Determining Cross-Section Areas 14
Measuring Duct Velocity 14
Troubleshooting and Maintenance 16
Troubleshooting Guide 16
Maintenance 17
General 17
Cleaning of the Velometer 17
Replacement Parts and Accessories 17
Replacement of the Range Selector Filter 17
Replacement of O-Rings in Probes 18
Replacement of O-Rings on the Meter 18
Calibration 18
Service Information 19
Instructions for Return 20
Ownership/Calibration Log 21

2
WARNING
!
USING THE VELOMETER SAFELY
All necessary precautions must be observed when operating the Velometer
in the vicinity of moving equipment such as motors and blowers. The user
must exercise care to ensure that the probe or the instrument does not in-
terfere with any moving equipment.
The maximum temperature at which the Velometer can be used is 250°F
(120°C). The maximum pressure difference between the inside of the in-
strument housing and ambient is 4.2 psi. (8.6 gm/cm2). The Velometer is
not designed for gas mixtures other than air.
Any use beyond the operational temperature or pressure limits, or on gas-
ses which are either combustible or may deteriorate materials in the
Velometer, is not recommended and is at the user’s risk.
Opening or otherwise attempting to service your Alnor instrument will void
the warranty. Please read the warranty statement carefully.
WARNING
!CAUTION

3
GENERAL DESCRIPTION
The Alnor Velometer is a direct reading instrument for measuring air ve-
locities. It is designed to measure velocities inside heating and ventilating
ducts, or in open areas such as at fume hoods, grilles, diffusers, slots on
ventilated plating tanks, and so forth. It may also be used for measuring
duct static pressures.
The Velometer set consists of the meter, velocity and static pressure Range
Selectors, measuring probes and connecting hoses.
The Velometer is basically an air flow meter reading in feet per minute (or
meters per second).
The Velometer is built with a taut band meter movement; it is carefully
balanced so that you may hold the meter in any normal position and still
get an accurate reading. All Velometers are uniformly calibrated to fac-
tory standards: optimum accuracy is attained when velometers are used with
accessories of the same set, and with the meter in the horizontal position
(scale window facing up).
Before using the Velometer, study the operational instructions and proce-
dures to insure proper use of the instrument for accurate results.
Meter
The meter receives air through its sensing ports. A force against the vane
causes a deflection of the needle which yields an indicated reading.
On the face of the meter there is a series of range scales (A) which enables
you to read accurately the measured value. Since there are a number of
ranges, it is important that the scale read on the meter face corresponds to
the velocity or static pressure range that is set on the Range Selector.
On the back side of the meter there are two sensing ports (hose connec-
tions) (B) which are for interconnecting to one of the two Range Selectors
with hoses. One port is marked positive (+) and the other negative (–).
Sensing port caps are provided and you should place them over the sens-
ing ports when the meter is not in use.
Check to see that the pointer is at zero each time the meter is put into service.
The zero adjustment screw (C) enables you to make an adjustment. With
the caps still on the ports, use a screwdriver to bring the pointer to zero. It
should continue to read zero whether the meter is lying flat, standing up-
right or is at any position in between, including the position where one end
of the scale is lower than the other.
ARange
Scales
BSensing
Ports
CZero
Adjustment
Screw

4
Range Selector
The Range Selector (A) allows you to switch to one of two velocity ranges
or a static pressure range by means of a switch plate (B).
A switch button (C) is provided for changing the Velometer from use with
a Pitot Probe to use with either a Diffuser Probe or a Static Pressure Probe.
When using the Pitot Probe, turn this button and allow it to spring out; when
using either the Diffuser Probe or a Static Pressure Probe, push the button in
and turn to lock it in position. In this position the switch button slot must be
vertical (aligned with arrows on label) for proper instrument operation.
Do not block switch button during operation.
WARNING
!CAUTION
The Range Selector is provided with a plug-in port (D) which accepts the
various probes and allows you to rotate them 360˚. (+) and (–) ports (E)
are provided for hose connections to the meter.
Depending on your model, your set will include one or two Range Selec-
tors that are identified by red or black lettering. This color coding relates
to the same colored scales on the meter.
Take-Up
Adjustment
Screw
A
Range Selector
BSwitch Plate
CSwitch Button
DPlug-In Port
EPort
Connections
F

5
The Range Selector with the black lettering has the following ranges:
Velocity: 0 to 1250 feet per minute
0 to 2500 feet per minute
Static Pressure: 0 to 1 inches of water (6000AP set)
The Range Selector with red lettering has the following ranges:
Velocity: 0 to 5000 feet per minute
0 to 10,000 feet per minute
Static Pressure: 0 to 10 inches of water
A take-up adjustment screw (F) is provided for tightening the switch plate
(B) which may work loose through normal wear. A noticeable effort to
change the setting of the switch plate will indicate proper tightness.
Pitot Probe
The Pitot Probe is designed to measure the velocity of air in ducts and also
in unrestricted areas such as air intakes at grinding/buffing wheels or ven-
tilation slots at plating tanks. For the procedure to measure duct velocities
see pages 13 and 14; for other applications see page 10.
The air intake (and discharge) for the probe is at (A). The probe should be
held at right angles to the air flow; an arrow at the base of the probe (C)
should point in the direction of the air flow.
The probe is marked in one-inch increments (B) for convenience in posi-
tioning the probe inside ducts.
The probe collar (D) acts as a stop when inserting the probe into the Range
Selector; an O-ring acts as a seal when the connecting leg is inserted into
the Range Selector.
Lo-Flow Probe
The Lo-Flow Probe is designed for measuring velocities below 300 feet
per minute in open spaces; it attaches directly to the meter without hoses.
An arrow (A) on the probe serves as a reminder of the direction you must
orient the probe and the meter when taking measurements.
Refer to page 10 for the proper velocity measuring procedure.
AVelocity
Sensing Port
BScale
CAir Flow
Direction
Indicator
DProbe Collar
EConnecting Leg
AAir Flow Direction Indicator

6
Diffuser Probe
The Diffuser Probe is designed to measure the velocity at diffusers, regis-
ters and grilles. The volume of air being supplied or exhausted can be deter-
minedbymultiplyingthe measuredvelocity timesan airflow factor.*Refer
to page 11 for proper diffuser, register and grille measuring procedures.
Thevelocitysensing port (A)senses thevelocityatthediffuser,register,or grille.
The snap-off fins (B) allow you to accurately position the probe vertically,
horizontally or radially.
The probe collar (C) acts as a stop when connecting the probe to the Range
Selector, and the O-ring acts as a seal.
The connecting leg (D) is inserted into the Range Selector.
* Air flow factors, sometimes known as “K” factors, are generally available from the manu-
facturer of the grille or diffuser.
Static Pressure Probe
The Static Pressure Probe is designed for measuring duct static pressure.
The rubber cap (A) provides a seal around the 1/4" hole (in the duct) where
measurements are to be taken.
The probe collar (B) acts as a stop when connecting the probe to the Range
Selector; the O-ring acts as a seal.
The connecting leg (C) is inserted into the Range Selector.
Refer to page 8 for the proper static pressure measuring procedure.
AVelocity
Sensing
Port
BSnap Off
Fins
CProbe
Collar
DConnecting
Leg
ARubber
Cap
BProbe
Collar
CConnecting
Leg

7
PREPARATION FOR USE
Diffuser Probe
Step 1: Remove sensing port caps.
Step 2: Connect two hoses (C) to sensing ports (B).
Step 3: Select proper Range Selector (D).
Note: For velocities below 2500 feet per minute, use the Range Se-
lector with black letters; for velocities above 2500 feet per minute,
use the Range Selector with red letters.
Step 4: Connect Range Selector (D) to loose ends of hoses (C) that are
already connected to the meter (A) as follows:
For Supply Measurements
Connect the plus (+) sensing port of the meter to the plus (+) sensing
port of the Range Selector, and the minus (–) sensing port of the meter
to the minus (–) sensing port of the Range Selector.
For Return and Exhaust Measurements
Connect the plus (+) sensing port of the meter to the minus (–) sens-
ing port of the Range Selector, and the minus (–) sensing port of the
meter to the plus (+) sensing port of the Range Selector.
Step 5: Insert Diffuser Probe (E) into the Range Selector (D). Push the
Diffuser Probe firmly down until the collar of the probe rests against the
top of the Range Selector.
Step 6: Check position of switch button (Da) on Range Selector (D). It
must be pushed in and turned to latch it in.
Step 7: Check position of switch plate (Db) on Range Selector (D). It must
be positioned for the proper velocity range.
Step 8: Proceed to make necessary velocity measurements; see page 11
for procedures.
Sensing
Ports
AMeter
B
CHose
Db Switch
Plate
Da Switch
Button
EDiffuser
Probe
Range
Selector
D

8
Static Pressure Probe
Step 1: Remove sensing port caps.
Step 2: Connect two hoses (C) to sensing ports (D).
Step 3: Select proper Range Selector (D).
Note: For 0–1" static pressures, use Range Selector with black let-
ters; for 1–10" static pressures, use Range Selector with red letters.
Step 4: Connect the hoses to the Range Selector (D) as follows:
For Positive Pressure Measurements
Connect the plus (+) sensing port of the meter to the plus (+) sensing
port of the Range Selector. Connect the minus (–) sensing port of
the meter to the minus (–) sensing port of the Range Selector.
For Negative Pressure Measurements
Connect the plus (+) sensing port of the meter to the (–) sensing port
of the Range Selector. Connect the minus (–) sensing port of the meter
to the plus (+) sensing port of the Range Selector.
Step 5: Select the proper Static Pressure Probe (E)
Note: For 0–1" static pressures, use the Static Pressure Probe with
black letters. For 1–10" static pressures, use the Static Pressure
Probe with red letters.
Step 6: Insert the Static Pressure Probe (E) into the Range Selector (D).
Push the probe firmly down until the collar of the probe rests against the
top of the Range Selector.
Step 7: Check position of switch plate (Da) on the Range Selector (D).
It must be pushed in and turned to lock it in position.
Step 8: Check position of switch plate (Db) on the Range Selector (D).
It must be to the extreme left.
Step 9: Proceed to make duct static pressure measurements. See page 13
for proper procedure.
AMeter
B
CHoses
Db Switch
Plate
Da Switch
Button
EStatic
Pressure
Probe
Range
Selector
D
Sensing
Ports

9
Pitot Probe
Step 1: Remove sensing port caps.
Step 2: Connect two hoses (C) to sensing ports (B).
Step 3: Select proper Range Selector (D).
Note: For velocities below 2500 feet per minute, use the Range Se-
lector with black letters; for velocities above 2500 feet per minute,
use the Range Selector with red letters.
Step 4: Connect the hoses to the Range Selector (D) as follows: The plus
(+) sensing port of the meter to the plus (+) sensing port of the Range
Selector and the minus (–) sensing port of the meter to the minus (–) sens-
ing port of the Range Selector.
Step 5: Insert the Pitot Probe (E) into the Range Selector (D). Push the
Pitot Probe firmly down until the collar of the probe rests against the top
of the Range Selector.
Step 6: Check position of switch button (Da) on Range Selector (D). It
must be released and left in the out position.
Step 7: Check position of switch plate (Db) on Range Selector (D). It must
be positioned for the proper velocity range.
Step 8: Proceed to make necessary duct velocity measurements. See page
13 for proper procedures.
Lo-Flow Probe
Step 1: Remove sensing port caps.
Step 2: Connect the Lo-Flow
Probe (F) directly to the meter (A)
by placing it onto the sensing ports
(B); no hoses are required. It fits
only one way onto the meter, with
the arrow pointing to the left when
viewing the meter from the front.
Db Switch
Plate
Da Switch
Button
Range
Selector
D
CHoses
A
Meter
B
Sensing
Ports
EPitot
Probe
Lo-Flow Probe F

10
OPERATION
After assembling the correct probe to the Velometer as shown on pages
7–9 you are ready to take the necessary measurements. Below
are some typical applications and cautions when using the various probes.
When using the Velometer for measuring air velocity at conditions
other than .075 lbm/ft3refer to the correction chart on page 19 for
maximum accuracy.
Procedure for Measuring Velocity with Lo-Flow Probe
1. Place the meter where you wish to measure the air flow.
If you are holding it, keep it at arm’s length and stand so
you do not obstruct the flow of air past the meter.
2. Hold the meter so that the arrow on the probe points in the
direction of air flow; if the direction is not known, turn the
meter until you observe the maximum pointer deflection.
3. Read the air velocity on the 0 to 300 FPM scale.
4. Record the reading on an appropriate air balancing worksheet.
Velocities at Suction Openings—Except Diffusers or Grilles
At Grinding or Buffing Wheels:
When measuring velocities at grinding or buffing wheels, use the Pitot Probe
or the Lo-Flow Probe. The head of the probe should be held in a plane
defined by the outside edge of the hood.
At Spray Booths:
When measuring the velocity at spray booths, use the Lo-Flow Probe. The
head of the probe should be placed in a plane defined by the outside edge
of the spray booth.
Velocities at Plating Tanks:
To measure the velocity at plating tanks, use the Pitot Probe. The probe
should be held close to the exhaust port of the tank, with the arrow on the
probe pointing toward the exhaust port.

11
Procedure for Measuring Diffuser, Register and Grille
Velocities with Diffuser Probe
To calculate the air volume passing through a diffuser, register or grille
outlet, measure the velocity at the outlet, applying the air flow factor that
is provided by the outlet manufacturer, and use the following equation:
Q = K xV
Where English Units Metric Units
Q = Volume flow rate ft3/min m3/s
K = Manufacturer’s flow factor — —
V = Average measured velocity ft/min m/s
Instructions for positioning the Diffuser Probe at the outlet for measuring
the velocity, as well as an appropriate flow factor, are available from the
outlet manufacturer. Shown below is a typical example:
Typical Diffuser Air Flow Measuring Procedure
To determine the volume of air discharged, a Velometer with a Diffuser
Probe may be used as shown below.
Note that the bottom of the positioning fins on the probe are level with
(and touching) the bottom of the intermediate spinning of the diffuser. The
probe is held vertically. The flow factors shown in the accompanying table
are applied to an average of six velocity readings taken at equally spaced
positions around the periphery of the diffuser.
Diffuser Air Flow
Size Factor
10 0.42
12 0.66
14 0.9
17 1.3
20 1.8
24 2.8
32 4.9
40 7.7

12
For maximum accuracy, observe the following precautions:
1. Use only the appropriate diffuser, register or grille
manufacturer’s measuring procedures.
2. Make a complete and accurate velocity reading.
3. Record the velocity measurements on a diffuser air balanc-
ing worksheet as shown.
AIR BALANCING—DIFFUSER READINGS
4. When the procedures instruct you to apply an average veloc-
ity reading, divide the opening into a number of equal areas
and determine an average of single readings taken at the cen-
ter of the equal areas.
5. When making a record of the measurements, include room
location, outlet model, flow factor, design air volume if
known, measured outlet velocity and calculated air volume.

13
Procedure for Measuring Static Pressure
1. Select the location for the static pressure reading and drill a
1/4" hole. You may wish to paint a circle around the hole and
number it for future convenience.
2. Assemble the Velometer for positive (or negative) readings
as described above.
3. Place the rubber cup of the probe firmly over the hole, and
read the static pressure on the black or red “Inches of Water
Gauge” scale.
4. Record the reading on an appropriate air balancing worksheet.
Fan Inlet
Fan
Discharge
Procedure for Air Flow Measurement in Ducts
To calculate the air volume passing through a duct, measure the average
velocity inside the duct, determine the cross-sectional area of the duct, and
apply the following equation:
Q = A xV
Where English Units Metric Units
Q = Volume flow rate ft3/min m3/s
A = Cross-section area ft2m2
V = Average duct velocity ft/min m/s

14
Determining Cross-Section Areas
The cross-section of the duct is based on the actual inside duct area through
which air flows. If the duct is internally lined with insulation, the thick-
ness of that insulation must be taken into consideration when calculating
the duct area.
Example: 24" wide x12" high duct with no internal insulation
has a cross-section area of 2 square feet.
38" wide x14" high duct with 1" internal insulation
has a cross-section area of 3 square feet.
Measuring Duct Velocity
The velocity of an air stream in a duct is not uniform throughout the cross-
section; air near the walls moves more slowly due to friction. Elbows, tran-
sitions and obstructions also cause variations in the velocity at any one
cross-section.
To obtain the average velocity in ducts of 4" diameter or larger, drill a 1/2"
diameteror largerhold inthe ductand takea seriesof ductvelocity readings
(commonly referred to as a traverse) with the Pitot Probe at points of equal
areaacross the duct.A formal patternof sensingpoints is recommendedand
these points are referred to as traverse point readings. Shown are recom-
mended velocity reading point locations for traversing round and square
(or rectangular) ducts.
Note: Pitot Probe Stations Indicated By .
Round Duct Traverse Points Square and Rectangular
Duct Traverse Points
Centers Of
Equal Areas
R
0.316R
0.548R
0.707R
0.837R
0.949R
Centers of
Equal Concentric
Areas

15
In round ducts, take velocity readings at the center of equal concentric areas;
take at least 20 readings along two diameters. In square or rectangular ducts,
take a minimum of 16 and a maximum of 64 readings at centers of equal
areas. Calculate the average of all readings.
For maximum accuracy, observe the following precautions:
1. Perform the traverse in a section of the duct where the air
stream is as uniform as practical. This is generally a location
of eight or more duct diameters of straight duct upstream from
the traverse location.
2. Do not take the traverse near a duct elbow, transition or
obstruction.
3. Make a complete, careful and accurate traverse and record
the results on a worksheet.

16
TROUBLESHOOTING AND MAINTENANCE
Troubleshooting Guide
Problem Correction
1. Velometer not adjusted. See zero adjust-
ment method, page 3.
2. Assembled probe and meter accidentally
reading pressure or aiflow. Check adjust-
ment with caps on sensing ports.
3. If Velometer does not remain at zero in all
positions it should be returned to the fac-
tory for calibration.
1. Different probes being used. The same
probe should be used on both ranges.
2. Wrong probe being used. See pages 7–9 for
correct application.
3. Measurement technique is different. Hold
probe in the same way, and at the same
place in the air flow, on all ranges.
4. Different Range Selector in use. Be sure
that both Range Selectors are in operating
condition: O-rings not worn, filters clean.
5. Range Selector switch not in operating
position. Switch plate must be at either
extreme of its travel.
1. Verify that the proper probe is being used.
2. Check for leaks in the O-rings on sensing
ports, Range Selector and probe. Replace
if necessary.
3. Filter in the Range Selector needs to be
cleaned.
4. Wrong scale is being read, or Range Se-
lector switch not set properly.
5. Hoses are not 24 in. long. Do not use hoses
that are different (longer or shorter) than
thoseoriginallyprovidedwiththeVelometer.
1. Airflowisbeingblockedbyoperator’shands.
2. Hand on the switch button of Range Selec-
tor. (See page 4.)
3. Hoses or probe not connected.
1. Probe not being used properly. (See section
ofmanualdescribinguseofspecificprobes.)
2. Hose connections must be reversed, either
at the Range Selector or at the meter.
Reading not the same
from range to range.
Velometer not at zero
(before use).
Readings are low.
No readings.
Negative readings.

17
Maintenance
General
Alnor Velometers require very little service except for replacement of
O-ring gaskets and cleaning or replacing the filter elements in the Range
Selectors. If any difficulties in the operation of the Velometer should de-
velop, please contact Alnor Instrument Company. Do not return any in-
struments without written authorization from Alnor Instrument Company.
Cleaning of the Velometer
In case it is necessary to clean the exterior of the meter, use a damp cloth
or a cloth moistened with alcohol and wipe the exterior carefully. Do not
rub excessively. DO NOT USE CARBON TETRACHLORIDE.
Replacement Parts and Accessories
In case additional parts are required to convert one Velometer set to an-
other, or in case broken or damaged parts must be replaced, order the parts
from the factory. All parts are interchangeable and no specific calibration
of probes is required with any particular instrument; simply specify the
Alnor number of the replacement part or accessory.
Replacement of Range Selector Filter
To replace the filter of the Range Selector, proceed as follows:
Remove the two Phillips Head screws on the collar above the Range Selec-
torswitch. Exert slightpressureto hold theupper and lowerhalf of theRange
Selector assembly together to permit easy withdrawal of the two screws.
Carefullypull the upperandlower half ofthe Range Selectorassembly apart.
Replaceable Parts
(A) Filter 321-012-005
(B) O-Ring 342-006-055
Phillips Oval Head Screws
Handle Receptacle
Probe Socket
Filter Element (A)
Air Vent Switch Button
“O” Ring (B)
Range Switch Knob
Switch Plate
Switch Housing Assembly
Take Up
Adjustment Screw

18
Withdraw the filter Part Number 321-012-005. Carefully clean the filter
element by means of a brush or vacuum cleaner, or wash it in luke-warm
water with grit-free soap. In case the filter element is damaged, replace it.
Before reassembling the Range Selector, carefully clean all parts.
To install the cleaned or replacement filter, slip the bore of the filter over
the protruding nipple portion of the lower Range Selector part. Place the
filter element onto the lower Range Selector part with the open end down.
Then slip the probe socket over the protruding nipple portion. Carefully
align all three outside diameters of the lower Range Selector part, the filter
and the probe socket. Slip all three parts into the upper Range Selector
housing so that the air vent switch button protruding from the lower Range
Selector assembly aligns with the channel in the upper Range Selector as-
sembly. Exert slight pressure when inserting the Phillips Head screw and
lightly tighten both Phillips Head screws.
Replacement of O-Rings in Probes
To replace the O-ring in the probes remove the old O-ring by means of a
hook-shaped tool, or by squeezing. Clean the O-ring groove before install-
ing the new O-ring. Slip the new O-ring in place and apply a thin film of
Silicone grease or lubricant on the outside of it. The O-ring Part Number
342-006-048 fits all Velometer probes.
Replacement of O-Rings on the Meter
Replace the O-rings of the meter connection ports first by removing the
old O-rings using a hood or by squeezing; clean the grooves and then slip
new O-rings Part Number 342-006-030 in place.
Calibration
Your Velometer should be returned to the factory for checking and/or
calibration six months after first use, and thereafter at least once a year,
depending on how it is used.
It should be carefully packed according to the return instructions on
page 21.
Alnor Instrument Company
7555 N. Linder Avenue
Skokie, IL 60077
Attention: Service Department

19
SERVICE INFORMATION
ContactAlnor InstrumentCompany before returning your AlnorInstrument
to the factory. See Instructions For Return. Follow the procedure carefully
asit will expediteprocessing. Failure tofollow the procedurewill/may cause
return of unit unrepaired. Send your instrument to the factory transportation
prepaid.Toassure fast turn-aroundtime,fill out thisformwithas much detail
as possible and attach it to the instrument.
Instrument Model____________________________________________
Serial Number ______________________________________________
Date of Purchase ____________________________________________
Where Purchased ____________________________________________
Describe Malfunction ________________________________________
Describe Environment ________________________________________
Return Instrument to:
Name _____________________________________________________
(Your name or company)
Address ____________________________________________________
Telephone __________________________________________________
Address Correspondence to:
Name _____________________________________________________
Address ____________________________________________________
Telephone __________________________________________________