TEC DG-1000 User manual

TRUEFLOW®AIR HANDLER
FLOW METER
USING THE DG-1000 WITH THE
TRUEFLOW AIR HANDLER FLOW METER

2
ENERGY CONSERVATORY WARRANTY
EXPRESS LIMITED WARRANTY:
Seller warrants that this product, under normal use and service as described in the operator’s manual, shall be free from defects in work-
manship and material for a period of 24 months, or such shorter length of time as may be specied in the operator’s manual, from the date of
shipment to the Customer.
LIMITATION OF WARRANTY AND LIABILITY:
This limited warranty set forth above is subject to the following exclusions:
1. With respect to any repair services rendered, Seller warrants that the parts repaired or replaced will be free from defects in workman-
ship and material, under normal use, for a period of 90 days from the date of shipment to the Purchaser.
2. Seller does not provide any warranty on nished goods manufactured by others. Only the original manufacturer’s warranty applies.
3. Unless specically authorized in a separate writing, Seller makes no warranty with respect to, and shall have no liability in connection
with, any goods which are incorporated into other products or equipment by the Purchaser.
4. All products returned under warranty shall be at the Purchaser’s risk of loss. The Purchaser is responsible for all shipping charges to re-
turn the product to The Energy Conservatory. The Energy Conservatory will be responsible for return standard ground shipping charges.
The Customer may request and pay for the added cost of expedited return shipping.
The foregoing warranty is in lieu of all other warranties and is subject to the conditions and limitations stated herein. No other express or
implied warranty IS PROVIDED, AND THE SELLER DISCLAIMS ANY IMPLIED WARRANTY OF FITNESS for particular purpose or merchant-
ability.
The exclusive remedy of the purchaser FOR ANY BREACH OF WARRANTY shall be the return of the product to the factory or designated
location for repair or replacement, or, at the option of The Energy Conservatory, refund of the purchase price.
The Energy Conservatory’s maximum liability for any and all losses, injuries or damages (regardless of whether such claims are based on
contract, negligence, strict liability or other tort) shall be the purchase price paid for the products. In no event shall the Seller be liable for any
special, incidental or consequential damages. The Energy Conservatory shall not be responsible for installation, dismantling, reassembly or
reinstallation costs or charges. No action, regardless of form, may be brought against the Seller more than one year after the cause of action
has accrued.
The Customer is deemed to have accepted the terms of this Limitation of Warranty and Liability, which contains the complete and exclusive
limited warranty of the Seller. This Limitation of Warranty and Liability may not be amended or modied, nor may any of its terms be waived
except by a writing signed by an authorized representative of the Seller.
TO ARRANGE A REPAIR: Visit energyconservatory.com/calibration-repair/ and download the Equipment Service Form. Complete the form
and return with the product. You may also call The Energy Conservatory at 612-827-1117 before sending any product back for repair or to
inquire about warranty coverage. All products returned for repair should include a return shipping address, name and phone number of a
contact person concerning this repair, and the purchase date of the equipment.
Manual Edition: June 2019
Copyright 2019. The Energy Conservatory, Inc. All rights reserved.

3
INTRODUCTION TO THE TRUEFLOW® AIR HANDLER FLOW METER
The air ow rate through residential air handlers is an important variable in estimating and optimizing the performance of heat pumps,
air conditioners and furnaces. Numerous eld studies of installed heating and cooling systems around the United States have found that
insufcient air ow across the indoor coil is an extremely common problem. Low air ow can lead to decreased heating and cooling system
capacity, increased energy use and comfort problems.
The most widely used methods for estimating the air handler ow rate, (the temperature rise method, static pressure and fan curve method,
and the Duct Blaster® isolated return method) have been found to be either problematic or time-consuming to perform. The Energy Con-
servatory’s TrueFlow® Air Handler Flow Meter is designed to provide a simple and accurate measurement of air ow through residential air
handlers rated from 1 to 5 tons. The TrueFlow Meter temporarily replaces the lter in a typical air handler system during the airow measure-
ment procedure. If the lter location is directly adjacent to the air handler, the TrueFlow Meter will measure the total air handler ow. If the
lter is located remotely at a single central return, the TrueFlow Meter will measure the airow through the central return.
Note: If the return duct system is very airtight, the air ow through the single central return will be very close to the total air handler ow.
Extensive eld testing of the TrueFlow Meter has shown that it:
• Is easy and fast to use in the eld. The TrueFlow Meter provides direct CFM readings in approximately 2 to 4 minutes without extensive
calculations or setup. The TrueFlow Meter requires about the same time as the single-point temperature rise method, when including the
time required in the temperature method to measure the output capacity.
• Can be used in a wide range of return plenums and air handler fan congurations. Adjustable sizing of the TrueFlow Meter allows it to t
most standard lter slots. Custom adjustments for unusual lter sizes can be easily made by the operator.
• Has a ow accuracy of +/ 7% for most applications when used with a pressure gauge having an accuracy of 1% of reading. The TrueFlow
Meter is approximately 4 times more accurate than the single-point temperature rise method, and of comparable accuracy to the Duct
Blaster isolated return method.
• Is applicable to many systems for which the temperature rise method cannot be used due to inadequate or absent supply plenum tem-
perature measurement points.
• Can be used with any manometer which has a resolution of 1 Pascal or 0.005 In H2O.

4
SYSTEM COMPONENTS OF THE TRUEFLOW® AIR HANDLER FLOW METER
The TrueFlow Air Handler Flow Meter consists of the following
components:
• 2 calibrated Metering Plates.
• 8 spacers which attach to the Metering Plates to provide for
sizing adjustments.
• 1 static pressure probe.
• Flow conversion tables used to convert Metering Plate
pressure measurements to ow in Cubic Feet per Minute.
• 10 feet of blue tubing and 30 feet of clear tubing.
• Operation manual.
• Carrying case.
METERING PLATES
The TrueFlow Meter includes 2 Metering Plates (#14 and #20), each
comprised of a clear plastic plate with a series of round metering holes and
black pressure sensing grids. Each plate has H-channel gasket attached to
all 4 sides. The H-channel gasket provides a seal around the Metering Plate
when it is installed in a lter slot, and also provides an attachment channel
to attach spacers to the plate. Two Metering Plates are provided due to the
large range of lter sizes possible in residential air handling systems.
The Metering Plates are installed in place of the system air lter, which
is always located in the return side of the duct system. The front side of
the Metering Plate has the TEC label and logo on it, as shown to the right,
and needs to be facing “upstream” into the airow (i.e. away from the air
handler fan). The 2 tubing connections to the plate’s pressure sensing grids
are located on the front side of the plate.
Air ow through the Metering Plate is determined by measuring the
pressure difference between the two sensing grids on the plate. The
measured pressure difference is converted to air ow in Cubic Feet per Minute using a ow conversion. Each metering plate contains two
tubing connections to the pressure sensing grids. The Red tubing connection provides a pressure signal from the plate’s “total pressure”
grid. The Green tubing connection provides a pressure signal from the plate’s “static pressure” grid.
SPACERS
The TrueFlow Meter comes with 8 spacers which are used to adjust the size of the Metering
Plates. The 2 Metering Plates and 8 spacers are compatible with the following 12 standard
lter sizes :
Table 1: Standard Filter Sizes Compatible with the TrueFlow Meter
Plate #14: 14 x 20 14 x 25 16 x 20 16 x 24 16 x 25 18 x20
Plate #20: 20 x 20 20 x 22 20 x 24 20 x 25 20 x 30 24 x 24
Each spacer consists of a clear plastic plate with H-channel gasket attached to three sides.
Spacers are attached to the Metering Plate by pushing the open side of the spacer into the
attachment channel found on the Metering Plate H-channel. Install the spacer so that the
outside edge of the gasket on the spacer and the Metering Plate line up with each other.

5
SYSTEM COMPONENTS OF THE TRUEFLOW® AIR HANDLER FLOW METER
It is sometimes necessary to attach two spacers to a Metering Plate at the same time.
Attaching the second spacer is done in the same manner as the rst spacer - push the open
side of the second spacer into the attachment channels found on the Metering Plate and
rst spacer. Install the second spacer so that the outside edge of the gasket on the spacer
and the Metering Plate line up with each other.
Table 2 below lists the combination of Metering Plates and spacers needed to adjust the
TrueFlow Meter to the 12 most commonly found lter sizes.
Table 2: Metering Plate and Spacer Selection Guide
Filter Size (in. x
in.)
Flow Metering
Plate
Spacer Dimen-
sion (in. x In.)
Spacer 1 Spacer 2
14 x 20 #14 ------ ------
14 x 25 #14 5 x 14 ------
16 x 20 #14 2 x 20 ------
16 x 24 #14 2 x 20 4 x 16
16 x 25 #14 2 x 20 5 x16
18 x 20 #14 4 x 20 ------
20 x 20 #20 ------ ------
20 x 22 #20 2 x 20 ------
20 x 24 #20 4 x 20 ------
20 x 25 #20 5 x 20 ------
20 x 30 #20 10 x 20 ------
24 x 24 #20 4 x 20 4 x 24
To use the Selection Guide, locate the lter slot size in the “Filter Slot” column. Determine the TrueFlow Metering Plate and spacers needed
by referring to the “Flow Metering Plate” and “Spacer Dimension” columns. For example, a 16” x 25” lter slot requires the #14 Metering
Plate, along with the 2” x 20” and 5” x 16” spacers.
Note: If you need to match a lter slot size that is not listed in the Selection Guide, custom sized spacers can be cut from any 3/32” or 1/8”
thick material (e.g. plastic sheet or cardboard). These custom spacers can be attached to the Metering Plates in the same manner as the
standard spacers, or they can be taped to the edge of the Metering Plate. In addition, the H-channel gasket can be temporarily removed (by
removing the gasket fastener plugs) to reduce the size of the Metering Plates or spacers.
Adding a single spacer
Adding a second spacer
STATIC PRESSURE PROBE
The TrueFlow Meter comes with one static pressure probe. During the air ow
measurement procedure, the operator will need to measure the operating pressure in
the duct system, both with the existing lter in place and with the TrueFlow Meter in
place. These two operating pressure measurements are used to adjust the measured
air ow through the Metering Plate for differences in resistance between the existing
lter and the TrueFlow Meter.

6
USING THE DG-1000 WITH THE TRUEFLOW AIR HANDLER FLOW METER
BASIC OPERATION
MEASURING THE NORMAL SYSTEM OPERATING PRESSURE
1. Measure the Normal System Operating Pressure (NSOP) with the existing lter in place
(replace if it is dirty) by installing a static pressure probe into the ductwork at one of
the 3 locations listed below:
• Insert the static pressure probe into the side surface of the supply plenum. The
static pressure probe should point into the airstream.
• Or, insert the tip of the static pressure probe into a “dead-end” corner of the supply
plenum.
• Or, insert the static pressure probe in the side surface of the return plenum.
2. Attach one end of the clear tube to the static pressure probe, and attach the other end to the Channel A
input tap.
3. Turn on the air handler fan to the desired speed.
4. Turn on the DG-1000 gauge by pressing and holding the power button
until the green light comes on and wait for the home screen to
appear.
5. Press Tubing Assistant. This will set-up the DG-1000 for proper conguration
and readings.
6. Press Air Handler.
7. Press Gauge Inside. (Most of the time measurements are
taken with the gauge inside, regardless of where the air
hanlder is. But if the guage is outside the building envelope,
press Gauge Outside.)
8. Press TrueFlow.
9. Continue with your selection or go back to make changes.
10. The tubing diagram appears. Connect the DG-1000 with the
proper tubing connections to the TrueFlow Meter and the air
handler. Press the play button.
11. Your DG-1000 is now ready to take measurements.

7
12. Press where it says “SET NSOP”. Since the air handler is already on and the tubing is
connected to the duct, the DG-1000 will display the static pressure in the duct work.
This number is used to adjust the air ow readings of the system when the TrueFlow
Meter is installed instead of the regular lter.
13. On Channel A the pressure of the system is being measured. On Channel B is the
number of seconds that have elapsed. Once the number on Channel A stabilizes, press
ENTER. The display will show the next steps to complete the measurement. When
ready press OK.
14. The display on Channel A will change from SET NSOP to SET TFSOP. You will also see
the amount of the adjust ment that will be made to the system pressure value during the
test and a CEAR button to start over with the NSOP.
MEASURING THE TRUEFLOW SYSTEM OPERATING PRESSURE
1. Turn off the air handler but keep the DG-1000 Gauge on.
2. Remove the lter from the lter slot
3. If the lter slot is larger than 14 x 20 or 20 x 20, add the
necessary spacers, as described earlier, to the plate of
choice to match the lter being removed.
4. Place the TrueFlow Meter into the lter slot, with the
front side with the lables facing into the airstream and
the tubes from the TrueFlow meter leading outside of
the lter slot area. Cover the lter slot area. Do not
pinch the tubes extending from the duct work.
USING THE DG-1000 WITH THE TRUEFLOW AIR HANDLER FLOW METER
Flexible tubing connections
Airow is moving right
to left so the front of
the plate faces into the
airow to the right.
Airow is moving from the bottom to the top so the front
of the plate faces down into the airow.
Airow is moving from the room into the duct so the
front of the plate faces into the room into the airow.
Keep grill door open during test.

8
USING THE DG-1000 WITH THE TRUEFLOW AIR HANDLER FLOW METER
5. Turn on the air handler.
6. Press on the PLATE area to select the correct size of plate that was installed in the lter
slot. (You will see that there is additional selections for a lter grill. There is a different
calibration value built into the DG-1000 to be used when the TrueFlow Meter is in a lter
grill. This provides a more accurate number to account for the different air ow pattern
that exists in a lter grill.)
7. Channel A will display the TFSOP and Channel B will display the ow in cfm.
8. Once the Channel A number stabilizes, activate hold to freeze the number on the screen.
Hold can be activated by touching the hand in the red status bar, or by double tapping in
either Channel A or Channel B.
9. Your test is now complete.
10. Turn off the air handler before removing the TrueFlow Meter. Remove the TrueFlow Meter,
return the orginal lter, cover the lter slot.
11. The results of the test are now compared to the air handler manufacturers specied value
for ow to determine next actions to take.
Specifications
Flow Accuracy: +/- 7% for most applications when used with a 1% pressure gauge (DG-1000). *
Flow Range: #14 Metering Plate: 365 cfm to 1,565 cfm.
#20 Metering Plate: 485 cfm to 2,100 cfm.
Nominal Size of #14 Metering Plate: 14.5 in. by 20.5 in. (with gasket material).
Metering Plates: #20 Metering Plate: 20.5 in. by 20.5 in (with gasket material).
System Weight: 13 lbs. (2 Metering Plates, 8 spacers, carrying case, tubing, static pressure probe, manual.)
* The accuracy of the TrueFlow Air Handler Flow Meter is installation dependent. The stated ow accuracy covers 95% of the typical instal-
lations documented during both the eld and laboratory testing of the device. Obstructions within 6 inches upstream or 2 inches downstream
of the Metering Plate that are blocking air ow through any of the metering holes may reduce the ow accuracy beyond the specications
listed here. Always follow the installation and operation instructions listed elsewhere in this manual.

9
Air Density Factors to Convert from Indicated Flow to Volumetric Flow
Temp. of air
through the
Metering Plate (F) 01000 2000 3000 4000 5000 6000 7000 8000 9000 10000
00.933 0.95 0.968 0.986 1.005 1.023 1.043 1.062 1.083 1.104 1.125
10 0.943 0.961 0.978 0.996 1.016 1.034 1.054 1.074 1.095 1.116 1.138
20 0.953 0.971 0.989 1.007 1.026 1.045 1.065 1.085 1.106 1.128 1.15
30 0.963 0.981 0.999 1.017 1.037 1.056 1.076 1.097 1.118 1.139 1.162
40 0.973 0.991 1.009 1.028 1.048 1.067 1.087 1.108 1.129 1.151 1.173
50 0.983 1.001 1.019 1.038 1.058 1.077 1.098 1.119 1.14 1.162 1.185
60 0.992 1.01 1.029 1.048 1.068 1.088 1.108 1.13 1.152 1.174 1.197
70 1.002 1.02 1.039 1.058 1.078 1.098 1.119 1.14 1.163 1.185 1.208
80 1.011 1.03 1.049 1.068 1.089 1.109 1.13 1.151 1.174 1.196 1.219
90 1.021 1.039 1.058 1.078 1.099 1.119 1.14 1.162 1.184 1.207 1.231
100 1.03 1.049 1.068 1.088 1.109 1.129 1.15 1.172 1.195 1.218 1.242
110 1.039 1.058 1.078 1.097 1.118 1.139 1.161 1.183 1.206 1.229 1.253
120 1.048 1.067 1.087 1.107 1.128 1.149 1.171 1.193 1.216 1.24 1.264
130 1.057 1.076 1.096 1.117 1.138 1.159 1.181 1.203 1.227 1.25 1.275
140 1.066 1.085 1.106 1.126 1.148 1.169 1.191 1.213 1.237 1.261 1.285
150 1.075 1.094 1.115 1.135 1.157 1.178 1.201 1.224 1.247 1.271 1.296
Volumetric Flow = Indicated Flow x Sqrt (0.075/air density) where air density is the density of air, in lbs/ft3, going through the
Metering Plate.
Temp. of air
through the
Metering Plate (F) 01000 2000 3000 4000 5000 6000 7000 8000 9000 10000
01.071 1.052 1.033 1.014 0.995 0.977 0.959 0.941 0.923 0.906 0.889
10 1.06 1.041 1.022 1.004 0.985 0.967 0.949 0.931 0.913 0.896 0.879
20 1.049 1.03 1.011 0.993 0.974 0.957 0.939 0.921 0.904 0.887 0.87
30 1.038 1.02 1.001 0.983 0.964 0.947 0.929 0.912 0.895 0.878 0.861
40 1.028 1.009 0.991 0.973 0.955 0.937 0.92 0.903 0.886 0.869 0.852
50 1.018 0.999 0.981 0.963 0.945 0.928 0.911 0.894 0.877 0.86 0.844
60 1.008 0.99 0.972 0.954 0.936 0.919 0.902 0.885 0.868 0.852 0.836
70 0.998 0.98 0.962 0.945 0.927 0.911 0.894 0.877 0.86 0.844 0.828
80 0.989 0.971 0.954 0.936 0.919 0.902 0.885 0.869 0.852 0.836 0.82
90 0.98 0.962 0.945 0.928 0.91 0.894 0.877 0.861 0.844 0.828 0.813
100 0.971 0.954 0.936 0.919 0.902 0.886 0.869 0.853 0.837 0.821 0.805
110 0.962 0.945 0.928 0.911 0.894 0.878 0.862 0.845 0.829 0.814 0.798
120 0.954 0.937 0.92 0.903 0.886 0.87 0.854 0.838 0.822 0.807 0.791
130 0.946 0.929 0.912 0.896 0.879 0.863 0.847 0.831 0.815 0.8 0.785
140 0.938 0.921 0.905 0.888 0.871 0.856 0.84 0.824 0.808 0.793 0.778
150 0.93 0.914 0.897 0.881 0.864 0.849 0.833 0.817 0.802 0.787 0.772
Air Density Factors to Convert from Indicated Flow to SCFM Flow
SCFM = Indicated Flow x Sqrt (air density/0.075) where air density is the density of air, in lbs/ft3, going through the Metering Plate.

10
TrueFlow
System
Operating
Pressure
in Pascals.
(TF SOP)
Normal System Operating Pressure in Pascals (NSOP)
NSOP / TFSOP Flow Resistance Correction Factor =
50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150
50 1.00 1.05 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.41 1.45 1.48 1.52 1.55 1.58 1.61 1.64 1.67 1.70 1.73
55 0.95 1.00 1.04 1.09 1.13 1.17 1.21 1.24 1.28 1.31 1.35 1.38 1.41 1.45 1.48 1.51 1.54 1.57 1.60 1.62 1.65
60 0.91 0.96 1.00 1.04 1.08 1.12 1.15 1.19 1.22 1.26 1.29 1.32 1.35 1.38 1.41 1.44 1.47 1.50 1.53 1.55 1.58
65 0.88 0.92 0.96 1.00 1.04 1.07 1.11 1.14 1.18 1.21 1.24 1.27 1.30 1.33 1.36 1.39 1.41 1.44 1.47 1.49 1.52
70 0.85 0.89 0.93 0.96 1.00 1.04 1.07 1.10 1.13 1.16 1.20 1.22 1.25 1.28 1.31 1.34 1.36 1.39 1.41 1.44 1.46
75 0.82 0.86 0.89 0.93 0.97 1.00 1.03 1.06 1.10 1.13 1.15 1.18 1.21 1.24 1.26 1.29 1.32 1.34 1.37 1.39 1.41
80 0.79 0.83 0.87 0.90 0.94 0.97 1.00 1.03 1.06 1.09 1.12 1.15 1.17 1.20 1.22 1.25 1.27 1.30 1.32 1.35 1.37
85 0.77 0.80 0.84 0.87 0.91 0.94 0.97 1.00 1.03 1.06 1.08 1.11 1.14 1.16 1.19 1.21 1.24 1.26 1.28 1.31 1.33
90 0.75 0.78 0.82 0.85 0.88 0.91 0.94 0.97 1.00 1.03 1.05 1.08 1.11 1.13 1.15 1.18 1.20 1.22 1.25 1.27 1.29
95 0.73 0.76 0.79 0.83 0.86 0.89 0.92 0.95 0.97 1.00 1.03 1.05 1.08 1.10 1.12 1.15 1.17 1.19 1.21 1.24 1.26
100 0.71 0.74 0.77 0.81 0.84 0.87 0.89 0.92 0.95 0.97 1.00 1.02 1.05 1.07 1.10 1.12 1.14 1.16 1.18 1.20 1.22
105 0.69 0.72 0.76 0.79 0.82 0.85 0.87 0.90 0.93 0.95 0.98 1.00 1.02 1.05 1.07 1.09 1.11 1.13 1.15 1.18 1.20
110 0.67 0.71 0.74 0.77 0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 1.00 1.02 1.04 1.07 1.09 1.11 1.13 1.15 1.17
115 0.66 0.69 0.72 0.75 0.78 0.81 0.83 0.86 0.88 0.91 0.93 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 1.12 1.14
120 0.65 0.68 0.71 0.74 0.76 0.79 0.82 0.84 0.87 0.89 0.91 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 1.12
125 0.63 0.66 0.69 0.72 0.75 0.77 0.80 0.82 0.85 0.87 0.89 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10
130 0.62 0.65 0.68 0.71 0.73 0.76 0.78 0.81 0.83 0.85 0.88 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.07
135 0.61 0.64 0.67 0.69 0.72 0.75 0.77 0.79 0.82 0.84 0.86 0.88 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.05
140 0.60 0.63 0.65 0.68 0.71 0.73 0.76 0.78 0.80 0.82 0.85 0.87 0.89 0.91 0.93 0.94 0.96 0.98 1.00 1.02 1.04
145 0.59 0.62 0.64 0.67 0.69 0.72 0.74 0.77 0.79 0.81 0.83 0.85 0.87 0.89 0.91 0.93 0.95 0.96 0.98 1.00 1.02
150 0.58 0.61 0.63 0.66 0.68 0.71 0.73 0.75 0.77 0.80 0.82 0.84 0.86 0.88 0.89 0.91 0.93 0.95 0.97 0.98 1.00
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50
10 1.00 1.10 1.18 1.26 1.34 1.41 1.48 1.55 1.61 1.67 1.73 1.79 1.84 1.90 1.95 2.00 2.05 2.10 2.14 2.19 2.24
12 0.91 1.00 1.08 1.15 1.22 1.29 1.35 1.41 1.47 1.53 1.58 1.63 1.68 1.73 1.78 1.83 1.87 1.91 1.96 2.00 2.04
14 0.85 0.93 1.00 1.07 1.13 1.20 1.25 1.31 1.36 1.41 1.46 1.51 1.56 1.60 1.65 1.69 1.73 1.77 1.81 1.85 1.89
16 0.79 0.87 0.94 1.00 1.06 1.12 1.17 1.22 1.27 1.32 1.37 1.41 1.46 1.50 1.54 1.58 1.62 1.66 1.70 1.73 1.77
18 0.75 0.82 0.88 0.94 1.00 1.05 1.11 1.15 1.20 1.25 1.29 1.33 1.37 1.41 1.45 1.49 1.53 1.56 1.60 1.63 1.67
20 0.71 0.77 0.84 0.89 0.95 1.00 1.05 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.41 1.45 1.48 1.52 1.55 1.58
22 0.67 0.74 0.80 0.85 0.90 0.95 1.00 1.04 1.09 1.13 1.17 1.21 1.24 1.28 1.31 1.35 1.38 1.41 1.45 1.48 1.51
24 0.65 0.71 0.76 0.82 0.87 0.91 0.96 1.00 1.04 1.08 1.12 1.15 1.19 1.22 1.26 1.29 1.32 1.35 1.38 1.41 1.44
26 0.62 0.68 0.73 0.78 0.83 0.88 0.92 0.96 1.00 1.04 1.07 1.11 1.14 1.18 1.21 1.24 1.27 1.30 1.33 1.36 1.39
28 0.60 0.65 0.71 0.76 0.80 0.85 0.89 0.93 0.96 1.00 1.04 1.07 1.10 1.13 1.16 1.20 1.22 1.25 1.28 1.31 1.34
30 0.58 0.63 0.68 0.73 0.77 0.82 0.86 0.89 0.93 0.97 1.00 1.03 1.06 1.10 1.13 1.15 1.18 1.21 1.24 1.26 1.29
32 0.56 0.61 0.66 0.71 0.75 0.79 0.83 0.87 0.90 0.94 0.97 1.00 1.03 1.06 1.09 1.12 1.15 1.17 1.20 1.22 1.25
34 0.54 0.59 0.64 0.69 0.73 0.77 0.80 0.84 0.87 0.91 0.94 0.97 1.00 1.03 1.06 1.08 1.11 1.14 1.16 1.19 1.21
36 0.53 0.58 0.62 0.67 0.71 0.75 0.78 0.82 0.85 0.88 0.91 0.94 0.97 1.00 1.03 1.05 1.08 1.11 1.13 1.15 1.18
38 0.51 0.56 0.61 0.65 0.69 0.73 0.76 0.79 0.83 0.86 0.89 0.92 0.95 0.97 1.00 1.03 1.05 1.08 1.10 1.12 1.15
40 0.50 0.55 0.59 0.63 0.67 0.71 0.74 0.77 0.81 0.84 0.87 0.89 0.92 0.95 0.97 1.00 1.02 1.05 1.07 1.10 1.12
42 0.49 0.53 0.58 0.62 0.65 0.69 0.72 0.76 0.79 0.82 0.85 0.87 0.90 0.93 0.95 0.98 1.00 1.02 1.05 1.07 1.09
44 0.48 0.52 0.56 0.60 0.64 0.67 0.71 0.74 0.77 0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 1.00 1.02 1.04 1.07
46 0.47 0.51 0.55 0.59 0.63 0.66 0.69 0.72 0.75 0.78 0.81 0.83 0.86 0.88 0.91 0.93 0.96 0.98 1.00 1.02 1.04
48 0.46 0.50 0.54 0.58 0.61 0.65 0.68 0.71 0.74 0.76 0.79 0.82 0.84 0.87 0.89 0.91 0.94 0.96 0.98 1.00 1.02
50 0.45 0.49 0.53 0.57 0.60 0.63 0.66 0.69 0.72 0.75 0.77 0.80 0.82 0.85 0.87 0.89 0.92 0.94 0.96 0.98 1.00
TrueFlow
System
Operating
Pressure
in Pascals.
(TF SOP)
Normal System Operating Pressure in Pascals (NSOP)
FLOW RESISTANCE CORRECTION FACTORS IN PASCALS

11
Normal System Operating Pressure in In. H2O (NSOP)
TrueFlow
System
Operating
Pressure
in In. H20
(TF SOP)
NSOP / TFSOP
Flow Resistance Correction Factor =
0.20 0.22 0.24 0.26 0.28 0.30 0.32 0.34 0.36 0.38 0.40 0.42 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 0.60
0.20 1.00 1.05 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.41 1.45 1.48 1.52 1.55 1.58 1.61 1.64 1.67 1.70 1.73
0.22 0.95 1.00 1.04 1.09 1.13 1.17 1.21 1.24 1.28 1.31 1.35 1.38 1.41 1.45 1.48 1.51 1.54 1.57 1.60 1.62 1.65
0.24 0.91 0.96 1.00 1.04 1.08 1.12 1.15 1.19 1.22 1.26 1.29 1.32 1.35 1.38 1.41 1.44 1.47 1.50 1.53 1.55 1.58
0.26 0.88 0.92 0.96 1.00 1.04 1.07 1.11 1.14 1.18 1.21 1.24 1.27 1.30 1.33 1.36 1.39 1.41 1.44 1.47 1.49 1.52
0.28 0.85 0.89 0.93 0.96 1.00 1.04 1.07 1.10 1.13 1.16 1.20 1.22 1.25 1.28 1.31 1.34 1.36 1.39 1.41 1.44 1.46
0.30 0.82 0.86 0.89 0.93 0.97 1.00 1.03 1.06 1.10 1.13 1.15 1.18 1.21 1.24 1.26 1.29 1.32 1.34 1.37 1.39 1.41
0.32 0.79 0.83 0.87 0.90 0.94 0.97 1.00 1.03 1.06 1.09 1.12 1.15 1.17 1.20 1.22 1.25 1.27 1.30 1.32 1.35 1.37
0.34 0.77 0.80 0.84 0.87 0.91 0.94 0.97 1.00 1.03 1.06 1.08 1.11 1.14 1.16 1.19 1.21 1.24 1.26 1.28 1.31 1.33
0.36 0.75 0.78 0.82 0.85 0.88 0.91 0.94 0.97 1.00 1.03 1.05 1.08 1.11 1.13 1.15 1.18 1.20 1.22 1.25 1.27 1.29
0.38 0.73 0.76 0.79 0.83 0.86 0.89 0.92 0.95 0.97 1.00 1.03 1.05 1.08 1.10 1.12 1.15 1.17 1.19 1.21 1.24 1.26
0.40 0.71 0.74 0.77 0.81 0.84 0.87 0.89 0.92 0.95 0.97 1.00 1.02 1.05 1.07 1.10 1.12 1.14 1.16 1.18 1.20 1.22
0.42 0.69 0.72 0.76 0.79 0.82 0.85 0.87 0.90 0.93 0.95 0.98 1.00 1.02 1.05 1.07 1.09 1.11 1.13 1.15 1.18 1.20
0.44 0.67 0.71 0.74 0.77 0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 1.00 1.02 1.04 1.07 1.09 1.11 1.13 1.15 1.17
0.46 0.66 0.69 0.72 0.75 0.78 0.81 0.83 0.86 0.88 0.91 0.93 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 1.12 1.14
0.48 0.65 0.68 0.71 0.74 0.76 0.79 0.82 0.84 0.87 0.89 0.91 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 1.12
0.50 0.63 0.66 0.69 0.72 0.75 0.77 0.80 0.82 0.85 0.87 0.89 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10
0.52 0.62 0.65 0.68 0.71 0.73 0.76 0.78 0.81 0.83 0.85 0.88 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.07
0.54 0.61 0.64 0.67 0.69 0.72 0.75 0.77 0.79 0.82 0.84 0.86 0.88 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.05
0.56 0.60 0.63 0.65 0.68 0.71 0.73 0.76 0.78 0.80 0.82 0.85 0.87 0.89 0.91 0.93 0.94 0.96 0.98 1.00 1.02 1.04
0.58 0.59 0.62 0.64 0.67 0.69 0.72 0.74 0.77 0.79 0.81 0.83 0.85 0.87 0.89 0.91 0.93 0.95 0.96 0.98 1.00 1.02
0.60 0.58 0.61 0.63 0.66 0.68 0.71 0.73 0.75 0.77 0.80 0.82 0.84 0.86 0.88 0.89 0.91 0.93 0.95 0.97 0.98 1.00
Normal System Operating Pressure in In. H2O (NSOP)
TrueFlow
System
Operating
Pressure
in In. H20
(TF SOP)
0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.24
0.04 1.00 1.12 1.22 1.32 1.41 1.50 1.58 1.66 1.73 1.80 1.87 1.94 2.00 2.06 2.12 2.18 2.24 2.29 2.35 2.40 2.45
0.05 0.89 1.00 1.10 1.18 1.26 1.34 1.41 1.48 1.55 1.61 1.67 1.73 1.79 1.84 1.90 1.95 2.00 2.05 2.10 2.14 2.19
0.06 0.82 0.91 1.00 1.08 1.15 1.22 1.29 1.35 1.41 1.47 1.53 1.58 1.63 1.68 1.73 1.78 1.83 1.87 1.91 1.96 2.00
0.07 0.76 0.85 0.93 1.00 1.07 1.13 1.20 1.25 1.31 1.36 1.41 1.46 1.51 1.56 1.60 1.65 1.69 1.73 1.77 1.81 1.85
0.08 0.71 0.79 0.87 0.94 1.00 1.06 1.12 1.17 1.22 1.27 1.32 1.37 1.41 1.46 1.50 1.54 1.58 1.62 1.66 1.70 1.73
0.09 0.67 0.75 0.82 0.88 0.94 1.00 1.05 1.11 1.15 1.20 1.25 1.29 1.33 1.37 1.41 1.45 1.49 1.53 1.56 1.60 1.63
0.10 0.63 0.71 0.77 0.84 0.89 0.95 1.00 1.05 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.41 1.45 1.48 1.52 1.55
0.11 0.60 0.67 0.74 0.80 0.85 0.90 0.95 1.00 1.04 1.09 1.13 1.17 1.21 1.24 1.28 1.31 1.35 1.38 1.41 1.45 1.48
0.12 0.58 0.65 0.71 0.76 0.82 0.87 0.91 0.96 1.00 1.04 1.08 1.12 1.15 1.19 1.22 1.26 1.29 1.32 1.35 1.38 1.41
0.13 0.55 0.62 0.68 0.73 0.78 0.83 0.88 0.92 0.96 1.00 1.04 1.07 1.11 1.14 1.18 1.21 1.24 1.27 1.30 1.33 1.36
0.14 0.53 0.60 0.65 0.71 0.76 0.80 0.85 0.89 0.93 0.96 1.00 1.04 1.07 1.10 1.13 1.16 1.20 1.22 1.25 1.28 1.31
0.15 0.52 0.58 0.63 0.68 0.73 0.77 0.82 0.86 0.89 0.93 0.97 1.00 1.03 1.06 1.10 1.13 1.15 1.18 1.21 1.24 1.26
0.16 0.50 0.56 0.61 0.66 0.71 0.75 0.79 0.83 0.87 0.90 0.94 0.97 1.00 1.03 1.06 1.09 1.12 1.15 1.17 1.20 1.22
0.17 0.49 0.54 0.59 0.64 0.69 0.73 0.77 0.80 0.84 0.87 0.91 0.94 0.97 1.00 1.03 1.06 1.08 1.11 1.14 1.16 1.19
0.18 0.47 0.53 0.58 0.62 0.67 0.71 0.75 0.78 0.82 0.85 0.88 0.91 0.94 0.97 1.00 1.03 1.05 1.08 1.11 1.13 1.15
0.19 0.46 0.51 0.56 0.61 0.65 0.69 0.73 0.76 0.79 0.83 0.86 0.89 0.92 0.95 0.97 1.00 1.03 1.05 1.08 1.10 1.12
0.20 0.45 0.50 0.55 0.59 0.63 0.67 0.71 0.74 0.77 0.81 0.84 0.87 0.89 0.92 0.95 0.97 1.00 1.02 1.05 1.07 1.10
0.21 0.44 0.49 0.53 0.58 0.62 0.65 0.69 0.72 0.76 0.79 0.82 0.85 0.87 0.90 0.93 0.95 0.98 1.00 1.02 1.05 1.07
0.22 0.43 0.48 0.52 0.56 0.60 0.64 0.67 0.71 0.74 0.77 0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 1.00 1.02 1.04
0.23 0.42 0.47 0.51 0.55 0.59 0.63 0.66 0.69 0.72 0.75 0.78 0.81 0.83 0.86 0.88 0.91 0.93 0.96 0.98 1.00 1.02
0.24 0.41 0.46 0.50 0.54 0.58 0.61 0.65 0.68 0.71 0.74 0.76 0.79 0.82 0.84 0.87 0.89 0.91 0.94 0.96 0.98 1.00
FLOW RESISTANCE CORRECTION FACTORS IN INCHES OF WATER COLUMN

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USING THE DG-1000 WITH THE TRUEFLOW AIR HANDLER FLOW METER