York G8C05012(MU,MD)B12, Техническое руководство

Страница: 7 / 8

270844-YTG-A-0407
Unitary Products Group 7
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 w.c., 0.60 w.c., etc.,) the system airflow
corresponds 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., 0.75 w.c., etc.), the static pressure
may be rounded to the nearest value in the table deter-
mining the airflow using Step 5 or calculate the airflow by
using the following example.
Example: For a 75,000 BTUH furnace with 2 return openings
and operating on high-speed blower, it is found that total sys-
tem static is 0.38” w.c. To determine the system airflow, com-
plete the following steps:
Obtain the airflow values at 0.30 w.c. & 0.40 w.c. ESP.
Airflow @ 0.30”: 1408 CFM
Airflow @ 0.40”: 1343 CFM
Subtract the airflow @ 0.30 w.c. from the airflow @ 0.40 w.c.
to obtain airflow difference.
1343 - 1408 = -65 CFM
Subtract the total system static from 0.30 w.c. and divide this
difference by the difference in ESP values in the table, 0.40
w.c. - 0.30 w.c., to obtain a percentage.
(0.38 - 0.30) / (0.40 - 0.30) = 0.8
Multiply percentage by airflow difference to obtain airflow
reduction.
(0.8) X (-65) = -52
Subtract airflow reduction value to airflow @ 0.30 w.c. to
obtain actual airflow @ 0.38 in. w.c. ESP.
1408 - 52 = 1356
1. Special floor base or air conditioning coil required for use on combustible floor.
2. Line contact only permitted between lines formed by the intersection of the rear panel and side panel (top in horizontal position) of
the furnace jacket and building joists, studs or framing.
*
Cabinet clearance is "0", vent clearance is required.
ACCESSORIES
Propane Conversion Kit (Standard) – 1NP0366
This accessory conversion kit may be used to convert natural
gas units for propane (LP) operation at altitudes 0-2,000 ft.
Conversion must be made by qualified distributor or dealer
personnel.
Propane Conversion Kit (High Altitude) – 1PS0467
This accessory conversion kit may be used to convert natural
gas units for propane (LP) operation at altitudes from 2,000 to
8,000 ft. Conversion must be made by qualified distributor or
dealer personnel.
Natural Gas Conversion Kit (High Altitude) – 1PS0466
This accessory conversion kit may be used to convert natural
gas units for high altitude operation at altitudes from 2,000 to
8,000 ft. Conversion must be made by qualified distributor or
dealer personnel.
Combustible Floor Base
This accessory is used for downflow applications on combus-
tible surfaces.
17-1/2" "B" Cabinets 1FB0318
21" "C"
Cabinets 1FB0319
24-1/2" "D" Cabinets 1FB0320
Bottom External Filter Rack
This accessory is used to upflow/bottom return air applica-
tions. Packaged and sold in quantities of six (6).
17-1/2" "B" Cabinets 1BR0312BK
21"
"C" Cabinets 1BR0316BK
24-1/2" "D" Cabinets 1BR0320BK
UNIT CLEARANCES TO COMBUSTIBLES
Application Top Front Rear Left Side
Right
Side
Flue
Floor /
Bottom
Closet Alcove Attic
Line
Contact
Upflow 1 6 0 0 0 6 Combustible Yes Yes Yes No
Upflow
B-Vent
1 2 0 0 0 1 Combustible Yes Yes Yes No
Horizontal 0 6 0 0 1 6 Combustible No Yes Yes
Yes(See Note
2
)
Horizontal
B-Vent
1 2 0 0 1 1 Combustible No Yes Yes
Yes(See Note
2
)
Downflow 1 6 0 0 5* 6
1" (See Note
1
)
Yes Yes Yes No
Downflow
B-Vent
1 2 0 0 0 1
1" (See Note
)
Yes Yes Yes No