Honeywell Perfect Window ER200 Instruction Manual page 9

Fig. 8. Airflow measurement grid.
Balancing Airflows
Balancing system airflow is important to verify the Fresh Air
Ventilation System is delivering the intended airflow.
Balancing is a good check for duct system blockages, fan
operation, and that system exhaust and supply pressure are
equal.
Honeywell 272672 Round Balancing Grid can be mounted in
the duct work connected to the Fresh Air Ventilation System
to balance the airflow. See Fig. 8. Grids can be used
temporarily or installed permanently to allow periodic check.
The grid is connected to a pressure measurement to translate
the pressure reading into an airflow reading (cfm or L/s) using
the table mounted on the grid or Table 1.
The grids must be used with a pressure measurement device
capable of measuring pressures ranging from 0 to 0.25 in. wc
(60 Pa). Use a magnehelic gauge or incline manometer,
available from your local wholesaler. A single pressure
measurement device can be used to measure airflow in both
Fresh Air Ventilation System air streams.
Measuring and Balancing Fresh Air Ventilation
System Airflows
One or two grids can be installed to take the measurements.
When using one, move it from the exhaust to the supply air
ducts to get the readings. Use the following procedure to get
accurate measurements:
Close all doors, windows and any other openings in the
building. Exhaust appliances (exhaust fans, furnace,
clothes dryer, water heater, etc.) must be off while
measuring airflow and balancing the Fresh Air
Ventilation System.
Insert the grid in the exhaust duct. Install so that the
arrow on the grid casing points in the direction of the
airflow in the duct work. Mount on the warm side of the
duct work where airflow turbulence from a fan blower,
duct elbow or damper is minimized. Turbulence can
result in incorrect airflow measurements. See Fig. 9.
NOTE: The magnehelic gauge or incline manometer
must be mounted on a level surface. Incline
manometers include a bubble-type level
indicator. When the unit is level, zero the
pressure measuring device. Magnehelic
gauges must be lightly tapped to verify
pressure reading before making any
adjustments or readings.
ER200 PERFECT WINDOW
PRESSURE TAPS;
CONNECT TO
MAGNEHELIC GAUGE
OR INCLINE
MANOMETER
M3101
9
™
FRESH AIR VENTILATION SYSTEM
Attach flexible tubing from the low pressure port on the
pressure gauge to the downwind tap on the airflow grid.
Seal the ductwork using duct tape.
Attach tubing from the high pressure tap on the
pressure measuring device to the upwind tap on the
airflow grid.
Turn on airflow and note the pressure registering on the
pressure measurement gauge. If the reading on the
pressure measuring device is negative, the pressure
connections are reversed and need to be changed.
Use the table on the airflow grid or Table 1 below to
translate the pressure measurement into an airflow
reading.
Table 1. Pressure To Airflow Conversion Chart For a
Seven-inch Airflow Grid.
Pressure
(in. wc)
cfm
0.010 73
0.015 89
0.020 103
0.025 115
0.030 126
0.035 136
0.040 145
0.045 154
0.050 162
0.055 170
0.060 178
0.065 185
0.070 192
0.075 199
0.080 205
0.085 211
0.090 218
0.095 223
0.100 229
0.105 235
0.110 240
0.115 246
0.120 251
0.125 256
0.130 261
0.135 266
0.140 272
NOTE: Check local codes for balancing requirements.
Normally the Fresh Air Ventilation System is
balanced at its highest speed; however, some
local codes require that the Fresh Air
Ventilation System be balanced at its normal
continuous speed.
Airflow
L/s
(34)
(42)
(48)
(54)
(59)
(64)
(68)
(73)
(76)
(80)
(84)
(87)
(90)
(94)
(97)
(100)
(103)
(105)
(108)
(111)
(113)
(116)
(118)
(121)
(123)
(126)
(128)
68-0131—2