Oriflow Cobra User manual

© Copyright 2017 ORIFLOW LLC
Operating Instructions for
Cobra and Lynx
Duct Leakage Testers
(Metric)

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
1
Table of Contents
Introduction
Introduction ……………………………………….…….. 2
Safety Precautions
Safety Precautions ………………………………….…. 2
Prior to Testing
Are You Using the Correct Tester? …………………… 3
System Preparation …………………….………………. 3
Power Requirements ………………………………….... 3
Extension Cord Requirements ……………………….... 4
Flex-Duct Length ………………………………………... 4
Determining Maximum Allowable Leakage ….……..... 4
Determining Which Orifice Plate to Use …………….... 5 - 6
Duct Leakage Test Setup and Procedure
Install Orifice Plate and Upper Tube Section ………… 7 - 8
Connect Flexible Duct to Orifice Tube ………………... 9
Connect Flexible Duct to Duct System ……………….. 9
System Test Pressure Connection ……………………. 10
Duct Leakage Test Setup (SUPPLY) …………………. 11
Duct Leakage Test Setup (RETURN/EXHAUST) …… 12
Zeroing Pressure Gauges ……………………………… 13
Avoiding Over-Pressurization ………………………….. 14
Obtaining System Test Pressure ……………………… 15
Determining Leakage Rate……………………………… 15 – 17
Troubleshooting
Can’t obtain system test pressure ……………………… 17
Zero reading on “DUCT SYSTEM” gauge ………….... 18
Zero reading on “ORIFICE TUBE” gauge …………….. 19
“ORIFICE TUBE” gauge reading maxed out………...... 19

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Introduction
These operating instructions are for ORIFLOW models COBRA and LYNX air
leakage testers. Take pride in knowing that you have purchased the best air leakage
tester on the market. It is no secret that Oriflow manufactures the highest quality
testers, and has unparalleled customer service and technical support.
The orifice plates available for your duct leakage tester are constructed from laser-
cut 1.6 mm stainless steel and do not require recalibration for 5 years. Note the
authority having jurisdiction may override this requirement, and if so, Oriflow has
reasonable rates for re-calibrating orifice plates manufactured by Oriflow.
Safety Precautions
Before operating your tester, read the following safety precautions:
DO NOT operate the tester in the rain,
DO NOT operate the tester while it is near or in water,
DO NOT operate the tester with a damaged electrical cord or plug,
DO NOT remove the inlet safety screen,
DO NOT touch the blower wheel when the unit is plugged in,
DO NOT look into the discharge end of the tester when the unit is plugged in,
DO NOT use the tester as a ladder or step stool,
DO NOT allow children near the tester,
DO use an extension cord of the proper gauge (see Table 2),
DO use the proper voltage and line frequency listed on the motor nameplate,
DO lock the caster when the tester is positioned horizontally,
DO use the tester on level ground,
DO secure the tester when transporting it,
DO wear proper hearing protection, safety glasses and work gloves,
DO seek assistance when lifting the tester (e.g., loading onto truck, going up
or down stairs).

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Prior to Testing
Are you Using the Correct Tester?
See Table 1 for the maximum capacity for each duct tester when using the largest
orifice plate.
Table 1 – Duct Leakage Tester Capacities
MaximumLeakageCapacity(L/s)*
Model250Pa500Pa.1000Pa1500Pa2000Pa.2500Pa3000Pa3500Pa4000Pa.
Lynx260L/s255L/s215L/s110L/s—————
Cobra310L/s305L/s285L/s220L/s95L/s————
Panther635L/s625L/s570L/s505L/s415L/s290L/s125L/s——
Rhino770L/s730L/s 670L/s630L/s560L/s490L/s420L/s310L/s225L/s
*–Usingthelargestsizedorificeavailableforthemodellisted.
System Preparation
Cap off all ends of system using clear plastic and duct tape or sheetmetal duct end
caps. Make sure you test the part of the duct system that leakage testing is required.
Usually, this is from the system fan up to, but not including, the VAV boxes (terminal
units). Refer to the engineer's specifications and all applicable codes and test
standards.
Power Requirements
Do you have an adequate power supply for your tester (see Table 2)?
Table 2 – Tester Amp Draw
Tester Model Voltage Flow Control
Option Full Load Amps
Lynx 115 Slide Gate 12.7
Cobra 115 Slide Gate 12.8
Cobra 115 VFD 14.0
Cobra 230 Slide Gate 6.4
Cobra 230 VFD 8.0

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Extension Cord Requirements
If you need an extension cord, is it the proper gauge? See Table 3 below for
extension cord requirements.
Table 3 – Required Extension Cord Wire Gauge
Tester Model Flow Control
Option Voltage Extension Cord
Length (meters) Wire Gauge
Lynx or Cobra Slide Gate 115 3 to 15 14
15 to 30 12
Cobra Slide Gate 230 3 to 50 14
15 to 30 14
Cobra VFD 115 3 to 50 14
15 to 30 12
Cobra VFD 230 3 to 50 14
15 to 30 14
Flex-Duct Length
Make sure you have enough flexible-duct with your tester for the job. Each tester
includes 3.8 m, which is enough for most applications. Extra lengths of flexible-duct
are available at www.oriflow.com/products.
Determining Maximum Allowable Leakage
To determine the maximum allowable leakage for the project, use ORIFLOW’s free
online programs to make these calculations (www.oriflow.com/programs).
In the U.S., calculations are done for either of the two typical specifications:
1. Percentage of system flow, or
2. SMACNA Leakage Class.
In Europe, Australia and other countries outside of the U.S., the following
specification is commonly used:
1. Pressure Classification (Class A, B, C or D)
If the specification uses SMACNA Leakage Class or Pressure Class, you will need to
calculate the total duct system surface area.
Oriflow has FREE Adobe forms available that will calculate duct surface area given
the duct shape, dimensions and length (www.oriflow.com/freeform). These forms
also calculate Leakage Factor, allowable leakage and Pass/Fail criteria among other
calculations.

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Determining Which Orifice Plate to Use
After determining the allowable leakage at the system test pressure, refer to the
following tables for the capacities of each orifice plate available for the Cobra and
Lynx model testers. The proper plate is the one where the specified allowable
leakage falls between the minimum and maximum leakage at the system static
pressure.
For example, if you are testing a system at 1000 Pa pressure and the maximum
allowable leakage is 165 L/s, you will need a 76 mm orifice plate if using the Cobra
tester (see Table 6) or a 102 mm plate if using the Lynx tester (Table 7).
Table 4 – Tester Capacities using the 25 mm Orifice Plate
System Static
Pressure
(Pa)
Minimum
Leakage*
(L/s)
COBRA Tester
Maximum
Leakage
(L/s)
LYNX Tester
Maximum
Leakage (L/s)
250
4.2 18 15
500 4.2 17 30
750 4.2 16 14
1000 4.2 14 13
1250 4.2 12 8
1500 4.2 10 5
2000 4.2 4.2 --
Table 5 – Tester Capacities using the 51 mm Orifice Plate
System Static
Pressure
(Pa)
Minimum
Leakage*
(L/s)
COBRA Tester
Maximum
Leakage
(L/s)
LYNX Tester
Maximum
Leakage (L/s)
250
16 73 61
500 16 71 59
750 16 68 57
1000 16 63 50
1250 16 59 40
1500 16 47 24
2000 16 17 --

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Determining Which Orifice Plate to Use (continued)
Table 6 – Tester Capacities using the 76 mm Orifice Plate
System Static
Pressure
(Pa)
Minimum
Leakage*
(L/s)
COBRA Tester
Maximum
Leakage
(L/s)
LYNX Tester
Maximum
Leakage (L/s)
250
39 196 165
500 39 193 160
750 39 184 151
1000 39 177 135
1250 39 160 109
1500 39 137 66
2000 39 54 --
Table 7 – Tester Capacities using the 102 mm Orifice Plate
System Static
Pressure
(Pa)
Minimum
Leakage*
(L/s)
COBRA Tester
Maximum
Leakage
(L/s)
LYNX Tester
Maximum
Leakage (L/s)
250
83 309 260
500 83 304 255
750 83 297 241
1000 83 283 215
1250 83 257 172
1500 83 219 109
2000 83 94 --

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Install Orifice Plate and Upper Tube Section
The orifice plate that was determined from the previous section should now be
installed with the serial number facing upwards so the corresponding calibration
certificate may be referenced after installation. Refer to Figures 1 through 4.
Figure 1 – Install Orifice Plate and then Rotate Clockwise
Figure 2 – Rotate Orifice Plate Clockwise until it Locks in Place

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Install Orifice Plate and Upper Tube Section (continued)
After the orifice plate is locked in place, place the upper tube section over the
bolt/wing nut set, rotate clockwise, and tighten wing nuts (Figures 3 and 4).
Figure 3 – Install Upper Tube Section and Rotate Clockwise
Figure 4 – Tighten Wing Nuts after Rotation

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Connect Flexible Duct to Orifice Tube
See Figure 5 below for securing one end of the flexible duct to the orifice tube. Note
that the worm-gear clamp should be slid over the flex-duct before connecting it to
the orifice tube. Slide the flexible duct so that it overlaps the orifice tube 50 to 75 mm,
and tighten clamp using a 8 mm nut driver.
Figure 5 – Installing Flex-Duct on Tube
Connect Flex-Duct to Duct System
Connect the 152 mm end of the flex-duct to the duct system. Find a convenient
location in the duct system where the tester has easy access. Make sure the
connection is a sturdy, sealed tight connection. You don’t want to create a leaky
connection thereby adding to the system leakage.
Figure 6 – Connection to Duct System

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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System Test Pressure Connection
Refer to Figures 7 and 8. To monitor the system static pressure, you need to drill a 8
mm diameter hole at least 1 m away from the flex-duct connection. Next, insert the
grey, plastic static pressure tap that is located on the end of the pressure tubing
coming from the “DUCT SYSTEM” gauge. Seal the pressure tap to the duct wall
using duct tape (Figure 7).
If the static pressure tap is missing, just insert end of pressure tubing from the
“DUCT SYSTEM” gauge so that 150 to 305 mm of tubing is inside the duct system.
Using putty or duct tape, seal the connection. See Figure 8.
Figure 7 – Connection to Duct System using Static Pressure Tap
Figure 8 - Static Pressure Tubing Connection
DUCT SYSTEM pressure
tubing inserted into duct
system

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Duct Leakage Test Setup (SUPPLY)
See Figure 9 for the test setup for SUPPLY duct system testing (positive pressure
testing). On the backside of the DUCT SYSTEM pressure gauge, move the pressure
tubing to the pressure port labeled SUPPLY SYSTEM.
Figure 9 – Duct Leakage Test Setup for a SUPPLY System

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Duct Leakage Test Setup (RETURN/EXHAUST)
Refer to Figure 10 for the test setup required to measure air leakage of a
RETURN/EXHAUST system (negative pressure testing). On the backside of the
DUCT SYSTEM pressure gauge, move the pressure tubing to the pressure port
labeled RETURN SYSTEM.
Connect the 152 mm end of the flex-duct to the inlet of the blower so that air from the
system is drawn into the blower. You will determine the leakage of the system since
the air drawn from the blower is discharged through the orifice plate which you are
measuring.
Figure 10 – Duct Leakage Test Setup for a RETURN/EXHAUST System

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Zeroing Pressure Gauges
Before you turn on the tester, make sure both gauges have been zeroed.
Zeroing Analog Gauges
Using a small slotted screwdriver, turn the zero-adjustment screw on the
gauge until the needle is aligned with the zero reading. Turning the screw
clockwise increases the pressure reading; turning it counterclockwise
decreases the reading. See Figure 11.
Figure 11 – Zeroing Analog Gauges
Zeroing Digital Gauges
First, turn on both gauges by pressing the black (or red) button located on the
backside of each gauge.
Use the following steps to zero each digital gauge:
1. Press MENU button once.
2. Press
▼arrow button until Adu shows on screen.
3. Press
Ebutton once to go into auto-zero mode
4. Press
Ebutton again and AUTO will be blinking on screen
5. Press
Ebutton a third time to complete the zeroing process.
6. Press MENU button two times to get back to the pressure reading.
7. Pressure should be reading zero or within +/- 4 Pa. If not, repeat
steps.

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Avoid Over-Pressurization
Prior to starting the blower, shut the inlet slide gate on models without the speed
controller option. For models with the VFD speed controller, press and hold the
DOWN button until the readout shows 10.00 (the lowest speed setting). If
powering up for the first time, the reading will already be at 10.00. See Figure 12.
Figure 12 – Avoid Over-Pressurizing by Minimizing Air Delivery upon Startup (inlet slide
model on left, VFD speed control model on right)
Obtaining System Test Pressure
Turn the blower on and slowly open the inlet slide gate (Figure 13) if your tester
has an inlet slide gate. If your tester has the VFD speed controller, press the green
RUN button, and then press the UP arrow button to increase fan speed.
Pressing and holding the UP button will increase speed more quickly. See
Figure 13.
Figure 13 – Obtaining System Test Pressure (inlet slide model on left, VFD speed control
model on right)

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Obtaining System Test Pressure (continued)
Regardless of tester model used, pay attention to the “DUCT SYSTEM” gauge while
increasing airflow. When you have reached the required system static pressure,
tighten the set-screw on the inlet damper (or STOP pressing the UP arrow button
on the speed controller).
Figure 14 – Duct System Gauge Reading (analog on left, digital on right)
Determining the Leakage Rate
Now that you have obtained the system test pressure, note the pressure reading of
the ORIFICE PLATE gauge (Figure 15). Refer to your calibration certificate to
determine the leakage rate that corresponds to the gauge reading. An example of a
calibration certificate is shown in Figure 16; it is for informational purposes only and
used in the example shown on the next page. Always refer to the calibration
certificate(s) that came with your calibrated orifice plate(s).
Figure 15 –ORIFICE PLATE Gauge Reading (analog on left, digital on right)

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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SAMPLE CALIBRATION CERTIFICATE
USE YOUR CERTIFICATE
Figure 16 – Example Calibration Certificate. Use the calibration certificate that came with your orifice
plate
Example (refer to Figures 15 and 16)
For an ORIFICE TUBE gauge reading of 725 Pa (Figure 15), the leakage
rate is approximately 235 L/s using the calibration certificate shown in
Figure 16 (see arrow).
For an exact value, use the equation that comes with every calibration
certificate. For the example shown in Figure 16:
Leakage = 8.733 x
where the value of “8.733” is a constant and will be specific to the orifice
plate used (every plate has its own value; yours will be different).
Using a calculator, take the square root of the gauge reading first, and then
multiply by the constant for your orifice plate (for this example, the constant
is "8.733"). The exact leakage is 8.733 x (square root of 725) = 235.1 L/s.

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Oriflow has a FREE Adobe format Duct Test Summary Sheet available that will
calculate the leakage, leakage factor, allowable leakage, Pass/Fail criteria and duct
surface area among other variables (www.oriflow.com/freeform). Files are available
for SMACNA or DW/143 requirements.
Troubleshooting
Can’t obtain system test pressure (THIS IS THE MOST COMMON ISSUE)
This happens when the system is leaking too much air. Make sure all outlets are
sealed. Check corners of rectangular duct for excessive leakage. Inspect all duct
and fitting joints for leakage. Make sure you seal all suspect joints and allow to cure
24 to 48 hours. Always refer to duct sealant manufacturer’s instructions.
Check for these other sources of leakage:
Rectangular duct joints (check and seal corners),
Fire or smoke dampers,
Duct joints (pay particular attention to flex-duct joints if they are part of the
leak test),
VAV boxes (pay particular attention to parallel box back draft dampers),
Built-up air handlers,
Plenums,
Uncured duct sealant blow-thru (follow manufacturer instructions for cure
time),
Improperly sealed joints,
Hot water coils and electric heaters,
Open duct end that was supposed to be sealed/capped-off for the leak test.
A non-toxic smoke machine is an excellent tool for locating significant sources of
leakage. Call ORIFLOW at 727-400-4881 or online at www.oriflow.com for more
information.

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Zero reading on “DUCT SYSTEM” gauge
If the gauge reading is zero, refer to the table below to fix this problem. Perform
troubleshooting steps in the order shown in the Table 7 below.
Table 7 –Troubleshooting steps when “DUCT SYSTEM” gauge is zero
Step Scenario What to do
1 Inlet damper was left shut,
cutting off air to the system. Open inlet damper slowly.
2 Pressure tubing connected
to gauge incorrectly
Look at the P1 and P2 stickers that are located on the
orifice tube and gauges. Make sure tubing from P1 tap
matches the P1 tap on the “ORIFICE TUBE” gauge.
3 Plugged fitting or
malfunctioning gauge.
Gently blow through other end of pressure tubing from
“DUCT SYSTEM” gauge, and watch needle increase
pressure reading.
4 System is leaking
too much air.
Check for these other sources of leakage:
Rectangular duct joints (check and seal corners),
Fire or smoke dampers,
Duct joints (pay particular attention to flex-duct
joints if they are part of the leak test),
VAV boxes (pay particular attention to parallel box
back draft dampers),
Built-up air handlers,
Plenums,
Uncured duct sealant blow-thru (follow
manufacturer instructions for cure time),
Improperly sealed or un-sealed joints,
Hot water coils and electric heaters,
Open duct end that was supposed to be
sealed/capped-off for the leak test.

© Copyright 2018 ORIFLOW LLC Rev: 03/2018
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Zero reading on “ORIFICE TUBE” gauge
If the gauge reading is zero, refer to the table below to fix this problem. Perform
troubleshooting steps in the order shown in Table 8 below.
Table 8 –Troubleshooting steps when “ORIFICE TUBE” gauge is zero
Step Scenario What to do
1 Inlet damper was left shut,
cutting off air to the system. Open inlet damper slowly.
2 Plugged pressure taps.
Remove pressure tubing from “ORIFICE TUBE” gauge, and
blow through each end to make sure the pressure taps on
the orifice tube are clear.
3 Orifice plate too large for
application.
If you are using a 102 mm ID orifice plate, and the system
is leaking 20 L/s, you probably won’t even notice the gauge
needle moving. This will happen to larger orifice plates too.
You need to use or purchase an orifice plate with a smaller
bore diameter so that a small amount of airflow/leakage will
result in a bigger pressure drop.
4 System is leaking very little
air.
You’ll know if this is true if the fan inlet is almost shut. Not
likely unless system is small. Fix is to use plate with
smaller bore diameter.
4 Pressure tubing connected
incorrectly.
Look at the P1 and P2 stickers that are located on the
orifice tube and gauges. Make sure they match.
5 Malfunctioning gauge.
Remove the clear pressure tubing from the lower pressure
tap on the orifice tube and blow through the end of the
tubing. The needle should move in response. If not, the
gauge is faulty.
6 Not sure
The best way to make sure that your tester is working
properly is to disconnect the flex duct from the system and
turn the blower on, and slowly open the inlet damper. If you
feel a lot of air coming out of the tube end, you should see
a pressure reading on the gauge “ORIFICE TUBE”.
“ORIFICE TUBE” gauge reading maxed out
Scenario 1: The system is leaking too much air. Make sure all outlets are
sealed. Check corners of rectangular duct for excessive leakage. Inspect all
duct and fitting joints for leakage. Make sure you seal all suspect joints and
allow curing time of 24 to 48 hours. Always refer to duct sealant
manufacturer’s instructions.
Scenario 2: orifice plate bore could be too small, causing a high pressure
drop at low to moderate flows. You need an orifice plate with a larger bore.
ORIFLOW LLC
www.oriflow.com
2125 Range Rd., Unit B
Clearwater, Florida 33765
727-400-4881 (phone)
877-420-7091 (fax)
[email protected]