Read these instructions carefully before using the DIFF. It is also important to read the instructions of the used battery charger.

Title : Observator DIFF Automatic Air Volume Flowmeter Version : Version 10.02-EN Date : 11 juni 2010 Author : C.W. Nasveld Read these instructions carefully before using the DIFF. It is also important to read the instructions of the used battery charger. Table of contents page 1 Introduction 2 2 Description and operation 2 2.1 General description 2 2.2 Operation comfort and ergonomics 3 2.3 Operation 3 2.4 Measuring positions 3 3 Practice 4 3.1 Battery information 4 3.2 First use 4 3.3 Battery life 5 3.4 Before using the DIFF 5 3.5 Adjusting the arms 5 3.6 General operation of the Electronics-unit 5 3.7 Turning on 5 3.8 Operation of the menu 5 3.9 Calibration 6 3.10 Measurement 7 3.11 Display settings Backlight and Contrast 7 3.12 Battery-indicator 8 3.13 Auto Off 8 3.14 Language 8 3.15 Measurement Unit 8 3.16 Temperature Unit 9 3.17 Switching the unit off 9 4 Optional Capture Hoods 9 5 Maintenance 10 6 Trouble shooting 11 6.1 Replacement of fuse 12 6.2 Optional items 12 6.3 Spare Parts 12 6.4 Service and recalibration 12 7 Specifications 13 8 Warranty 13 9 Data logging and downloading software DIFFiner 14 10 Declaration of Conformity 15 Page 1 of 15

1. Introduction Congratulations with buying the Observator DIFF Automatic Air Volume Flow Meter with pressure compensation. Full automatic measurement between 10,0 and 400 m3/hr (2,78-111 l/s and 5,89-235CFM) for exhaust and supply air. The standard delivery is consisting of a DIFF Automatic Air Volume Flow Meter, battery charger, 4 pieces SANYO NiMH batteries, calibration report and manual. Options are data logging with DIFFiner software and several fabric nylon hoods and a quick charger. 2. Description and Operation 2.1 General description This electronic portable instrument is special designed for accurate measurement of air volume flows of grilles, diffusers etc. Measurements are done by the ZEROMETHOD. This type of meter is written in the Dutch building resolutions NEN1087 en NEN8087 of the Dutch Normalization Institute. The pressure that is build-up by the instrument itself, because of the internal resistance, is by this zero method automatic compensated against the atmospheric pressure outside the instrument. The pressure compensation is done by a build-in, special designed, fan which is controlled by a differential pressure sensor. The indication is controlled by a sensor which is measuring the speed of the fan and is converted by the electronics in read-out in m3/h (also possibility to read-out in cfm or l/s). After 10-20 seconds (depending on the volumeflow) the digital instrument is indicating the air volume flow which for example is been blow-in or exhausted by a grill. The zero point is always maintained by the DIFF Automatic, which is essential by measurements of fluctuating flows. The meter is also recognizing the flow direction and is indicating the air temperature as well on the display. Accurate measurements can be done on almost all possible measures of blow and exhaust ornaments. It is possible to measure big grilles in parts because the DIFF is not disturbing the blow-in or exhaust air model of the grill. The sum of the measurement is the flow through the grill. Each DIFF is prepared for memory by SD-card. Please contact your local dealer or Observator for the necessary upgrade with pc-software DIFFiner and SD-card. The DIFF can be used for example in housing and utility. It is ideally suited for commissioning specialists, facilities managers, health and safety specialists, test engineers and ventilation installers. But the applications are very wide. Page 2 of 15

2.2 Operation comfort and ergonomics The DIFF is self adjusting for supply and exhaust grilles. You do not have to turn the instrument each time because it is recognizing the flow direction. So you always place the square side over or at the grill. The DIFF gives for flow directions calibrated values. You are able to position the DIFF, by the adjustable arms and display, so that it is easy to operate and to read-out. Because of those possibilities the use of a ladder is mostly unnecessary. 2.3 Operation The instrument is at measurement on a grill causing a difference in pressure between the pressure at the duct side and the room site. By this difference in pressure the air distribution will be influenced and this is causing a fault in measuring by other instrumentation. However the DIFF is measuring the difference in pressure and is compensating this by the build-in fan. In this situation the volume flow through the grill is exactly the same as it was before the DIFF was placed. After the beep you read-out the right volume flow. 2.4 Measuring positions On these pictures the right arms and display positions are shown. Do not place the arms in a straight position with the body of the DIFF. The measurements can be out of specification when the display is in front of the opening of the DIFF. Ceiling grills wall grills Ceiling grills 60x60 cm and line grills. Page 3 of 15

3. Practice 3.1 Battery information The DIFF is designed for modern rechargeable NiMH batteries with a capacity of 2700mAh as a minimum. Charge the SANYO batteries according the manual of the delivered charger (standard white charger 14 hours charging or when LED-indication is off). We suggest you use only the type of batteries and chargers that we delivered to you. Other brands have other specifications. The delivered chargers are carefully selected together with the delivered batteries and are protected against overload and high temperatures. All times we recommend to use the standard white charger instead of the quick charger (2 hours). Use only the quick charger as a stand-by. Charge the batteries in an ambient temperature of 0-50ºC when you use the standard charger. Charge the batteries in an ambient temperature of 10-40ºC when you use the quick charger. Non-rechargeable batteries such as Alkaline and Zinc lead batteries are not applicable for use with the DIFF. The range will drop down to 100 a 300 m3/h when you will use these type of batteries. It is also possible that the DIFF suddenly is switching off. Never try to charge these type of batteries! 3.2 First use Charge the batteries fully all times. After several times charging and discharging the batteries will have the full capacity. The batteries have to be for 14 hours in the charger or when de LED-indication is off. Turn off the instrument when you are replacing the batteries. The batteries are placed in the battery compartment on the backside of the electronics housing. Unscrew the thumb screw to open the cover of the compartment and to take out carefully the battery holder to replace the batteries. Watch the polarity by placing full loaded batteries! The electronics are protected by means of a fuse, see item 6.1. The battery positions are marked on the black battery holder. The stud is the + and the flat side is the of the batteries. Hold the wires by replacing the batteries above the batteries. The wires can be pinched off when they are positioned below the battery holder. Push the batteryholder to the right side of the compartment and replace the cover. You can work with the DIFF a couple off days with fully charged batteries with volume flows till 100m3/h before you have to recharge. The time of use is depending of the volume flows that are measured, (specification; 8 hours fan in continues operation at 75 m3/h). Tips for optimal use Cold batteries will deliver less power. Store the DIFF above the 5 ºC. Take care for an equal temperature of batteries and the DIFF. Prevent condensation. Page 4 of 15

3.3 Battery life The expected battery life of NiMH batteries with every day use of the DIFF will be one year. When you have to charge the batteries more often then normal then you have to buy new ones (Article no. AT-255). If you use every day these batteries we recommend you to use every year new (ca. 250 charge/discharge cycles). If you are using the DIFF less then we recommend you to use every two years new. The capacity becomes less if NiMH batteries become older or when you frequently use the quick charger. The resistance will be higher, this is why they will be warm during charging. The delivered chargers are protected against overheating. You have to throw used batteries away by local legal instructions. 3.4 Before using the DIFF Check if there are no loose objects in the funnel of the DIFF. 3.5 Adjusting the arms The arms of the instrument are adjustable. You are able to adjust these when you push the gray buttons on the turning-points simultaneously. The arms are clicking on different angles (every 30 ). You may choose for the angle at which you hold the instrument in the most pleasant way. You are also able to turn the electronics housing so that you easily read-out the display. Do not place the arms in a straight position with the body of the DIFF. The measurements can be out of specification when the display is in front of the opening of the DIFF. 3.6 General operation of the electronics-unit The operation of the DIFF is done by one single button. Readout by the display. 3.7 Turning On Push on the middle of the black button on the display housing. 3.8 Operation of the Menu On the LCD you see a Menu of which you can make a selection. The following selections are possible = = = = = M E N U = = = = = B A C K L I G H T C O N T R A S T - > O F F C A L I B R A T I O N M E A S U R E M E N T The arrow is marking the selection. When you are turning the button to the right the next item will be selected. Page 5 of 15

= = = = = M E N U = = = = = C O N T R A S T O F F - > C A L I B R A T I O N M E A S U R E M E N T B A C K L I G H T By turning the button to the left you select the item that is on top of the selected item. You are activating this by pressing the button in the middle. The arrow stays on its position and the list is scrolling further. The item at the bottom of the list is disappearing and is coming back on top of the list. 3.9 Calibration After you turn on the instrument calibration is necessary. With this calibration the ultra sensitive differential pressure meter will be adjusted to the ambient temperature. Tip: place the DIFF over an exhaust grill for 20 seconds for quick acclimatization before you do the calibration when you have big differences in temperature. To secure the accuracy it is necessary that you calibrate every half hour. When the ambient temperature is changing fast or when the DIFF is having another temperature, it is necessary to calibrate regurly. The calibration will be done as follows: Make sure the DIFF is placed on a flat surface and that there is no moving air through or above the DIFF. Activate CALIBRATION in the menu. You will see the following: = C A L I B R A T I O N = = C A L I B R A T I N G... The calibration is done in seconds. = C A L I B R A T I O N = = C A L I B R A T I N G... S U C C E S F U L You will return to the menu by pushing the black button. You may check the calibration to do a measurement. If it is ok then it shows 0 m3/h, l/s or cfm. When the measurement shows more then 0 m3/h, l/s or cfm the calibration failed. Try the calibration again and make sure the DIFF is placed on a flat surface and that there is no moving air through or above the DIFF. Page 6 of 15

If calibration fails all the time it is necessary to send the DIFF to Observator for factory calibration or repair. 3.10 Measurement Make selection MEASUREMENT in the menu after the calibration S U P P L Y A I R T E M P 2 2. 9 C A I R F L O W [ M 3 / H ] + 0. 0 Position the DIFF with the square side over or against the grill so that it is covering the whole area. With big grills you may divide the area in several parts and take the sum for total volume flow. Push now on the middle of the black button. Do not start the measurement when it is not placed over the grill yet! The DIFF will do first a pre-measurement. After this you will hear the motor speeding up. Then the DIFF will do the final measurement. Wait till the final measurement is done. Depending of the volume flow this may take a few till decades of seconds. The display is giving, during the measurement, the momentary value of the volume flow and the temperature. This value cannot be trusted as the DIFF is still busy to carry out the pressure compensation. You will hear a beep when the final measurement is done, the motor stops and the display shows the right volume flow, air temperature and flow direction. You may now remove the DIFF. S U P P L Y A I R T E M P 2 0. 9 C A I R F L O W [ M 3 / H ] + 3 8. 8 The + mark and the word SUPPLY is telling that it is a supply grill. The mark and the word exhaust is telling you that it is an exhaust grill By pushing the button again you are returning to the menu. The measured value is not available anymore. Note The motor can reach a rotation speed of a couple of thousand rotations per minute at high volume flows and that s why it is causing some noise The whistle sound that you will hear is caused by the motor control and is normal. By measurement above 400 m3/h the word OVERRANGE will appear and the motor will stop. 3.11 Display settings Backlight and Contrast With difficult light circumstances it may be necessary to adjust the level of the backlight. = = = = = = = = = = = = = = = B A C K L I G H T = = = = = = = = = = = = = = = D I F F D R I V E R = = = = = = = = = = = = = = = Page 7 of 15

With extreme low or high temperatures it can be necessary to adjust the contrast. Select CONTRAST in the menu. Turn on the button (to the left more dark and to the right more light) till the reading is satisfactory. This adjustment will be kept in memory when you turn off the instrument. = = = = = = = = = = = = = = = C O N T R A S T = = = = = = = = = = = = = = = D I F F D R I V E R = = = = = = = = = = = = = = = 3.12 Battery-indicator On the measurement screen you are be informed about the status of the battery. With one full block left you have to recharge the batteries. You may also select from the menu BATTERY. Select BATTERY in the menu. Is telling you how much power is left in the batteries. Can be not accurate because of: - Old batteries - Big temperature difference between batteries and electronics. = BATTERY == 075% With new batteries full load capacity will be reached after a several loadings. 3.13 Auto Off To save battery power the DIFF will be shut off automatically if it is not been used for 10 minutes. 3.14 Language Select your language = LANGUAGE == ENGLISH 3.15 Measurement Unit Select your unit = MEAS UNIT == M3/H Page 8 of 15

3.16 Temperature Unit Select your unit = TEMP UNIT == CELSIUS 3.17 Switching the unit off = OFF == 3.18 Over range protection The DIFF will switch off above 400m3/h and will show OVERRANGED and a not correct Airvolumeflow. See also 7.1 = OVERRANGED == 4. Optional Capture Hoods Capture hoods can be used when the measures of the grill you want to measure are to wide for the standard opening. You can do partial measurements and take the some of these or use one of the optional hoods. Please take care if you measure at high inducing squirrel grills, use in this case the cross. The cross is delivered with the hoods 60x60cm and 40x40cm. This cross can be placed with barbed tape after setting up the hood. The DIFF is having 4 points of support (internal corner) at the square side, to set up optional capture hoods with glass-fiber stiffening poles placing these diagonal to the hood frame. Place the DIFF on the round opening on the floor. Put from the top the double elastics over the square side. Pull the hood up and put one side against your body. Pull now at one side the elastics in their position (see picture). Pull now on both elastics. Place two stiffening poles (see picture). Now turn the whole for 180 degrees and pull the other side in its position and position the other stiffening poles. The stiffening poles are placed cross-wise. Page 9 of 15

Pull again on both elastics to make sure they are tight well. Each optional hood has its own set of poles. Flexing of the poles may be necessary. Place now if necessary the cross. 5. Maintenance The DIFF is a precision instrument. Some simple routine maintenance after each use will ensure that your DIFF will function correctly for many years. Remove any moisture droplets using a clean, absorbent cloth/paper before dissembling and storing the unit. Remove batteries if the unit is to be stored, unused for an extended period. Always store and transport the unit in the carry-case provided. Store in dry conditions. If stored in cold conditions, always allow the unit to warm to ambient temperatures before use. DO NOT remove the grills inside the DIFF. CHECK periodically for damage or any visible cracks. Instrument case may be wiped clean with a damp cloth and dried: DO NOT immerse the instrument in water. DO NOT use abrasive cleaning products. These will damage the case and scratch the display. Capture hood fabric can be wiped with a clamp cloth, if necessary, and moisture droplets dried with an absorbent cloth/paper. Periodically, wash in cold water using a mild detergent. Drip dry, ensuring it cannot become caught on any sharp objects. A repair set is delivered with the hood. A damaged hood will seriously affect the measurements taken. Page 10 of 15

ANTI-STATIC SOLUTION can be applied sparingly to the instrument by using a clean, lint-free cloth and carefully rubbing it over the instrument case and window. NOTE: This is normally only necessary when working in low humidity conditions. It is strongly recommended that the DIFF will be recalibrated each year. 6. Trouble shooting symptom diagnose Solution Battery indication one full square or 30% or lower Battery indication low while batteries are fully charges At high volume flows the DIFF is not switching off At high volume flows the DIFF is not switching off while battery set is fully charged. The DIFF will not turn on while pushing the black button After calibration the measurement is not 0 m3/h After several calibrations the measurement on the table is still not 0 m3/h Bad read-out of the display Display suddenly dark DIFF stops working (no display on LCD) Big variations in reading and or wrong flowdirection Indication OVERRANGED and a not correct value Batteries are old To less battery power. By 400 m3/h you need at least 80% battery power. By 10-350 m3/h you need at least 20% battery power Batteries are old Batteries empty Fuse defect Calibration done while there is pressure difference because of draught or the instrument is not standing still Adjustment of contrast and backlight wrong Static electricity or auto power off because of low battery Not switched on. The AUTO-OFF feature will have turned off the instrument You started the measurement will the DIFF was not placed over the grill yet You are trying to measure above the range of 400 m3/h Recharge your set of batteries Place a new fully charged set of batteries Recharge the set of batteries Place a new fully charged set of batteries Recharge the batteries Replace the fuse Make sure the DIFF is placed on a flat surface and that there is no moving air above the DIFF. Please send the DIFF back to Observator for repair of factory calibration Adjust these, see item 3.11. Replace the batteries or recharge Push on the middle of the black button to activate the DIFF again Place the DIFF over the grill before you start the measurement Lower the volumeflow true the grill of take measurements in parts Page 11 of 15

During a measurement motor stops for a moment You are measuring at the lower end of the measuring range around the 10 m3/h Keep the DIFF over de grill. De motor will start again and the measurement will be finished 6.1 Replacement of fuse The DIFF is containing a fuse 5x20 mm 250V / 5A slow. The fuse holder is positioned in the right side of the display/electronics-housing. You may open the fuse holder by turning with a big flat screwdriver. Please check if the batteries are placed in the right position before placing a new fuse. 6.2 Optional items articlenumber Description AT-251 Quick charger for 4xAA NiMH batteries (2 hours at 2700 mah batteries). Power supply 100-240V AT-255 Set (4 pcs) of rechargeable batteries AA 2700mAh NiMH AT-240 Fabric Hood 310x1534mm incl. frame and fiber rods AT-241 Fabric Hood 310x1234mm incl. frame and fiber rods AT-245 Fabric Hood 600x600mm incl. cross, frame and fiber rods Fabric Hood 400x400mm incl. cross, frame and fiber rods AT-260 Upgrade data logging with pc-software DIFFiner and SD-card 6.3 Spare parts articlenumber AT-300-130 AT-300-140 AT-255 AT-250 AT-280 CL-DIFF Description Glassfuse 5x20mm 5AT Battery Holder Wire Battery Holder Set (4 pcs) of rechargeable batteries AA 2700 mah NiMH Charger for 4xAA NiMH batteries (13 hours at 2700 mah batteries). Power supply 100-240V. Incl. set of batteries. Fiberrod of Hood 400x400mm Fiberrod of Hood 600x600mm Fiberrod of Hood 310x1234mm Fiberrod of Hood 310x1534mm Carrying case Calibration-service. 12-points (supply and exhaust) calibration with certificate. 6.4 Service and recalibration If the instrument appears not to be working correctly or requires re-calibration, contact your nearest Observator agent or the Observator NL Service Department. For re-calibration it is not necessary to supply an optional hood. Page 12 of 15

7. Specifications Measures (250x250)x510xØ200mm Weight 2.9 kg with batteries, without transport case Working conditions -10 tot +50 ºC, 0-95% RV None condensating Measuring range 10-400 m3/h and -15 tot +70 ºC Accuracy ±3% from reading ±1 m3/h, ±1ºC. Resolution display Resolution zero pressure meter Power supply 0,1<100>1 m3/h, 0,1 ºC. < 0,2 Pa 4x 1,2 V AA NiMH 2700 mah, rechargeable Auto power off Measuring time Housing material Method of measuring EMC Moisture protection Battery life Low battery or after when not used for 10 minutes <30 seconds. Depending of Volume flow ABS plastic According Dutch NEN1087/1088/8088 According EN60132-1, IEC61000-5-5 etc IP20 according IEC-60529 8 hours fan in continuous operation at 75 m3/h. Measured with the delivered Sanyo 2700 mah batteries 8. Warranty Free replacement of defective parts during a period of 12 months from date of delivery. From warranty excluded are damages caused by improper use or handling Page 13 of 15

9. Data logging and downloading software It is possible to order (AT-260) an upgrade of your DIFF together with pc-software DIFFiner and 2GB SD-card. With this possibility you will get a measurement report of the measured installation(s). In the MENU you will get the function STORAGE. When this function is not available yet or you will be asked for a code, please contact your dealer or Observator Instruments. Below you will find the instruction for use after purchasing the upgrade: Download the pc-software DIFFiner from the website www.observator.com//airtechnology/support. Place the SD-card (if necessary through the optional USB-adapter, in your PC. Start now the DIFFiner-software Select the SD-card Create the project you want to measure. Create a database for ROOM TYPES, GRILLE TYPES, GRILLE POSITIONS and GRILLE SITUATIONS. With the arrows you are able to create a default on top of the list. Fill in the known design data of each BUILDING. With the button NEW below the page you select the ROOMS out of the created database. SAVE the data when you have completed the data Place now the SD-card in the DIFF (left side of the display) Select STORAGE Select now the PROJECT you want Select the BUILDING you want Select the ROOM you want to measure Select the GRILLE you want to measure Check the grille details and change if necessary Select MEASUREMENT The design flow is marked as D and the measured value as M. The situation of the grille can be changed under S. The type of grille can be changed under T. The position can be changed under = P. After a measurement you have the choice to measure again. The final measurement will be stored after selecting en pressing the enter function. Take out the SD-card when you are finished and place it into the DIFF. Open DIFFiner and select your PROJECT and press OPEN. Press now PRINT for a report in HMTL-version or EXCEL for export to Excel. In Excel you may do other extra calculations and include you company-logo. With the EXCEL-button under PROJECT you are able to print more reports simultaneously. When you just want to see the data you select your building and klik on OPEN. Under PROJECT, OPEN, EXPORT you are able to store the data on an other location on your PC. Under PROJECT, OPEN, IMPORT you are able to import a file. In precaution DIFFiner will create an other name. The design data can be duplicated under BUILDING and OPEN. Page 14 of 15

10. Declaration of Conformity Page 15 of 15