Filter Performance - Pressure Drop Inches W.c; Applying Filter Pressure Drop To Determine System Airflow - Luxaire G8D08016UHB11 Technical Manual

036-21013-002 Rev. A (5/00)
FILTER PERFORMANCE
The airflow capacity data published in Blower Performance
Table above, represents blower performance WITHOUT fil-
ters. To determine the approximate blower performance of
the system, apply the filter drop value for the filter being used
or select an appropriate value from the Table below.

FILTER PERFORMANCE - PRESSURE DROP INCHES W.C.

Minimum Opening Size
Airflow Range
1 Opening
0 - 750 230
751 - 1000 330
1001 - 1250 330
1251 - 1500 330
1501 - 1750 380
1751 - 2000 380
2001 & Above 463
* Hogs Hair Filters are the type supplied with furnace (if supplied).
APPLYING FILTER PRESSURE DROP TO
DETERMINE SYSTEM AIRFLOW
To determine the approximate airflow of the unit with a filter in
place, follow the steps below:
1. Select the filter type.
2. Select the number of return air openings or calculate the
return opening size in square inches to determine the
proper filter pressure drop.
3. Determine the External System Static Pressure (ESP)
without the filter.
4. Select a filter pressure drop from the table based upon
the number of return air openings or return air opening
size and add to the ESP from Step 3 to determine the
total system static.
5. If total system static matches a ESP value in the airflow
table (i.e. 0.20, 0.60, etc,) the system airflow corre-
sponds to the intersection of the ESP column and Model/
Blower Speed row.
6. If the total system static falls between ESP values in the
table (i.e. 0.58, 0.75, etc.), the static pressure may be
rounded to the nearest value in the table determining the
airflow using Step 5 or calculate the airflow by using the
following example.
4
2
(in. )
Disposable
2 Openings 1 Opening
0.01
0.05
0.10
0.10
658 0.15
658 0.19
658 0.19
NOTE: The filter pressure drop values in Blower Performanc-
eTables are typical values for the type of filter listed and
should only be used as a guideline. Actual pressure drop rat-
ings for each filter type vary between filter manufacturer.
Filter Type
Hogs Hair
2 Openings 1 Opening
0.01
0.05
0.10
0.10
0.09 0.14
0.11 0.18
0.11 0.18
Example: For a 120,000 Btuh furnace with 2 return openings
and operating on high speed blower, it is found that total sys-
tem static is 0.58" w.c. To determine the system airflow, com-
plete the following steps:
1. Obtain the airflow values at 0.50" & 0.60" ESP.
Airflow @ 0.50": 2130 CFM
Airflow @ 0.60": 2050 CFM
2. Subtract the airflow @ 0.50" from the airflow @ 0.60" to
obtain airflow difference.
2050 - 2130 = -80 CFM
3. Subtract the total system static from 0.50" and divide this
difference by the difference in ESP values in the table,
0.60" - 0.50", to obtain a percentage.
(0.58 - 0.50) / (0.60 - 0.50) = 0.8
4. Multiply percentage by airflow difference to obtain airflow
reduction.
(0.8) x (-80) = -64
5. Subract airflow reduction value from airflow @ 0.50" to
obtain actual airflow @ 0.58" ESP.
2130 - 64 = 2066
*
Pleated
2 Openings 1 Opening
0.15
0.20
0.20
0.25
0.08 0.30
0.10 0.30
0.10 0.30
Unitary Products Group
Luxaire
2 Openings
0.17
0.17
0.17