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TABLE 15: Filter Performance - Pressure Drop Inches W.C. and (kPa)
Airflow Range
3
CFM
m
/min
0 - 750
0 - 21.4
751 - 1000
21.25 - 28.32
1001 - 1250
28.33 - 35.40
1251 - 1500
35.41 - 42.48
1501 - 1750
42.49 - 49.55
1751 - 2000
49.56 - 56.63
2001 & Above
56.64 - Above
APPLYING FILTER PRESSURE DROP TO
DETERMINE SYSTEM AIRFLOW
To determine the approximate airflow of the unit with a filter in place, fol-
low 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 pres-
sure 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 w.c. (50 Pa), 0.60 w.c. (150 Pa), etc,) the system airflow cor-
responds 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 w.c. (144 Pa), 0.75 w.c. (187 Pa), 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.
TABLE 16: Field Installed Accessories - Non Electrical
MODEL NO.
1NP0347
1PS0313
1PS0314
1SR0302
1SR0200
1BR0114
1BR0214
1BR0117
1BR0217
1BR0121
1BR0221
1BR0124
1BR0224
1HF0801
Unitary Products Group
Minimum
Opening Size
2
2
in
cm
230
1484
330
2129
330
2129
330
2129
380
2452
380
2542
463
2987
DESCRIPTION
PROPANE (LP) CONVERSION KIT
HIGH ALTITUDE PRESSURE SWITCH KIT
(Does Not Include Orifices)
SIDE RETURN FILTER KIT 1" FILTER
SIDE RETURN FILTER KIT 1-4" FILTER
BOTTOM RETURN FILTER KIT 1" FILTER
BOTTOM RETURN FILTER KIT 1-4" FILTER
BOTTOM RETURN FILTER KIT 1" FILTER
BOTTOM RETURN FILTER KIT 1-4" FILTER
BOTTOM RETURN FILTER KIT 1" FILTER
BOTTOM RETURN FILTER KIT 1-4" FILTER
BOTTOM RETURN FILTER KIT 1" FILTER
BOTTOM RETURN FILTER KIT 1-4" FILTER
INTERNAL FILTER KIT WITH 1" FIBER FILTER
Disposable
Washable Fiber
In W.C.
kPA
In W.C.
0.01
0.00249
0.01
0.05
0.01245
0.05
0.10
0.02491
0.10
0.10
0.02491
0.10
0.15
0.03736
0.14
0.19
0.04733
0.18
0.19
0.04733
0.18
Example: For a 60,000 BTUH (17.58 kW) furnace with a bottom return
opening and operating on high-speed blower, it is found that total sys-
tem static is 0.58" w.c. To determine the system airflow, complete the
following steps:
Obtain the airflow values at 0.50 w.c. (125 Pa) & 0.60 w.c. (150 Pa)
ESP.
Airflow @ 0.50": 1250 CFM (35.4 m
Airflow @ 0.60": 1180 CFM (33.4 m
Subtract the airflow @ 0.50 w.c. (125 Pa) from the airflow @ 0.60 w.c.
(150 Pa) to obtain airflow difference.
1180 - 1250 = -70 CFM (-12 m
Subtract the total system static from 0.50 w.c. (125 Pa) and divide this
difference by the difference in ESP values in the table, 0.60 w.c.
(150 Pa) - 0.50 w.c. (125 Pa), to obtain a percentage.
(0.58 - 0.50) / (0.60 - 0.50) = 0.8
Multiply percentage by airflow difference to obtain airflow reduction.
(0.8) X (-70) = -56
Subtract airflow reduction value to airflow @ 0.50 w.c. (125 Pa) to
obtain actual airflow @ 0.58 in. w.c. (144 Pa) ESP.
1250 - 56 = 1194
272312-UIM-A-0407
Filter Type
Pleated
kPA
In W.C.
0.00249
0.15
0.01245
0.20
0.02491
0.20
0.02491
0.25
0.03487
0.30
0.04484
0.30
0.04484
0.30
3
/min)
3
/min)
3
/min)
USED WITH
ALL MODELS
40, 57, 80, 100
MBH
120
MBH
ALL MODELS
ALL MODELS
14-1/2" CABINETS
14-1/2" CABINETS
17-1/2" CABINETS
17-1/2" CABINETS
21" CABINETS
21" CABINETS
24-1/2" CABINETS
24-1/2" CABINETS
ALL MODELS
kPA
0.03736
0.04982
0.04982
0.06227
0.07473
0.07473
0.07473
27
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