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.Determine the External System Static Pressure (ESP) without the filter.
3.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.
4.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.
5.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.
UNIT CLEARANCES TO COMBUSTIBLES
Example: For a 130,000 Btuh furnace operating on high speed blower, it is found that total system static is 0.58" w.c. To determine the system airflow, complete the following steps:
1.Obtain the airflow values at 0.50" & 0.60" ESP.
Airflow @ 0.50": 2125 CFM
Airflow @ 0.60": 2035 CFM
2.Subtract the airflow @ 0.50" from the airflow @ 0.60" to obtain airflow difference.
2035 - 2125 =
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
5.Subract airflow reduction value to airflow @ 0.50" to obtain actual airflow @ 0.58" ESP.
2125 - 72 = 2053
APPLICATION | TOP | FRONT | REAR | LEFT | RIGHT | FLUE | FLOOR/ | CLOSET | ALCOVE | ATTIC | LINE | |
SIDE | SIDE | BOTTOM | CONTACT | |||||||||
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
| |
DOWNFLOW | 1 | 3 | 0 | 0 | 0 | 0 | 1"* | YES | YES | YES | NO | |
HORIZONTAL | 0 | 3 | 0 | 1 | 1 | 0 | COMBUSTIBLE | NO | YES | YES | YES† |
*. Special floor base or air conditioning coil required for use on combustible floor.
†.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.
ACCESSORIES
PROPANE (LP) CONVERSION KIT -
1NP0347 - All units
This accessory conversion kit may be used to convert natural gas (N) units for propane (LP) operation. Conversions must be made by qualified distributor or dealer personnel.
CONCENTRIC VENT TERMINATION -
1CT0302 (2") 1CT0303 (3")
For use through rooftop, sidewall. Allows combustion air to enter and exhaust to exit through single common hole. Elimi- nates unslightly elbows for a cleaner installation.
COIL TRANSITION KIT -
1TK0917 - 17” Furnace
1TK0921 - 21” Furnace
1TK0924 - 24” Furnace
Required in downflow applications when using G*FD series coils.
CONDENSATE NEUTRALIZER KIT - 1NK0301
Neutralizer cartidge has a 1/2" plastic tube fittings for installa- tion in the drain line. Calcium carbonate refill media is also avaiable from the Source 1 Parts (p/n
HIGH ALTITUDE PRESSURE SWITCHES -
Used to convert units for operation at altitudes from 4,500 ft. to 10,000 ft. Refer to table on page 3 for proper pressure switch application. For Application See
Unitary Products Group | 5 |
