Installation Manual

Blower Speed Selection
LEFT-HAND AIR
DISCHARGE (TOP VIEW)
TEST HOLES
AIR FLOW
Figure 7. Static Pressure Test
Cabinet
Vol: CFM
Drop: in. w.g.
Model Width in. Dry Wet
18/24ANPA
14.5 600 .11 .17
14.5 800 .18 .25
18/24BNPA
17.5 600 .11 .17
17.5 800 .18 .25
24ANPA 14.5 800 .16 .18
24BNPA 17.5 800 .16 .18
30ANPA 14.5 1000 .18 .20
30BNPA 17.5 1000 .18 .20
30/36ANPA
14.5 1000 .19 .21
14.5 1200 .27 .30
30/36BNPA
17.5 1000 .13 .16
17.5 1200 .17 .21
30/36CNPA
21 1000 .13 .16
21 1200 .17 .21
36ANPA 14.5 1200 .27 .30
36BNPA 17.5 1200 .17 .21
48BNPA
17.5 1400 .23 .24
17.5 1600 .30 .31
48CNPA
21 1400 .13 .16
21 1600 .16 .20
49CNPA 21 1600 .17 .22
50/60CNPA 21 1600 .23 .29
60CNPA 21 2000 .29 .34
60DNPA 24.5 2000 .21 .27
Table 2.
and the duct. Drill holes away from refrigerant piping.
avoid unit damage.
CAUTION
Proper air volume must be provided over the evaporator
coil. Select a blower motor speed tap that will provide 400
± 50 CFM per 12,000 Btu/h of cooling capacity (wet coil). A
static pressure reading must be taken to see if the pressure
drop falls within the proper range. See Table 2.
To ensure accuracy, air must be read from below the coil
an accurate reading.
1. Drill one 5/16” air test hole into the delta plate between
the coil slabs.
2. Drill one 5/16” air test hole into the duct above the top
of the coil.
3. Connect the instrument for static pressure
measurement hoses to the air entering side of coil.
end seal. Seal around holes with sealant.
4. Turn on electrical power to the furnace and set the
thermostat to initiate a cooling demand.
5. Table 2 lists air volumes and equivalent static pressure
readings for these units. Observe the static pressure
reading. If the reading is below the required air
volume, increase the blower speed; if the reading is
above the required air volume, decrease the blower
speed. Refer to the furnace wiring diagram for blower
speed settings.
6. When the required static pressure readings are
obtained, remove the test hose lines and insert snap
hole plugs into test holes.
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