Carrier 48N - Manual (Page 17)

Table 14—Model 48NT060 (Belt Drive) Air Delivery (Cfm) At Indicated External
Static Pressure (in. W.C.) (Dry Coil without Air Filter*)
End Discharge
EXTERNAL STATIC PRESSURE—INCHES WATER
PULLEY TURNS 208V 230V or 460V
RPM OPEN 0.0 0.2 0.4 0.6 0.8 0.0 0.2 0.4 0.6 0.8
1430 1 See Note #2 2761 2534 2343 2152 1965 2808 2588 2331 2189 2007
1380 2 2685 2444 2230 2035 1829 2716 2498 2282 2075 1864
1330 3 2583 2341 2129 1921 _ 2585 2355 2154 1921 —
1280 4 2445 2174 1960
— —
2454 2209 1966 1733 —
1230 5 2287 1964 1775 — — 2287 2028 1780 — —
Table 15—Model 48NT060 (Belt Drive) Air Delivery (Cfm) At Indicated External
Static Pressure (in. W.C.) (Dry Coil without Air Filter*)
Down Discharge
EXTERNAL STATIC PRESSURE—INCHES WATER
PULLEY TURNS 208V 230V or 460V
RPM OPEN 0.0 0.2 0.4 0.6 0.8 0.0 0.2 0.4 0.6 0.8
1430 1 See Note #2 2623 2407 2225 2044 1867 2667 2458 2243 2078 1906
1380 2 2551 2322 2118 1933 1737 2580 2373 2168 1971 1771
1330 3 2454 2221 2022 1825
— 2465 2237 2046 1825 —
1280 4 2323 2065 1862
— —
2331 2098 1867
— —
1230 5 2272 1866 — — — 2173 1927 — — —
NOTES: 1. Factory setting is 4 turns open.
2. Do not operate biower beiow 1 turn open on motor puiiey. Motor overheating may resuit.
3. Do not operate unit in cooiing mode at airfiow rate beiow 1750 cfm. Indoor coii icing may occur.
’Air delivery values are without air filter. Air delivery values are for dry coil. See Table 16, page 10 for coil pressure drop. Deduct field supplied filter pressure
drop and wet coil pressure drop to obtain external static pressure available for ducting.
Table 16—Wet Coil Pressure Drop
Airflow
(CFM)
Pressure Drop
(in. W.C.)
650 0.038
850 0.046
1050 0.066
1250 0.081
1450 0.111
1650 0.129
1850 0.150
2050 0.180
2250 0.198
A. Air Filter
A CAUTION
Never operate the unit without a suitable air filter in
the return-air duct system. Always replace the filter
with the same dimensional size and type as originally
installed. See Tables 2 thru 7 for recommended filter
sizes.
Inspect air filter(s) at least once each month and replace
(disposable-type) or clean (cleanable-type) at least twice dur­
ing each heating and cooling season or whenever the filter(s)
becomes clogged with dust and lint.
Replace filters with the seune dimensional size and type as
originally provided, when necessary.
B. Unit Top Removal
A CAUTION
Condenser fan and motor are fastened to the unit top.
When removing the top, use extreme care to not puU
the fan motor leads loose.
NOTE: When performing maintenance or service procedures
that require removal of the unit top, be sure to perform all
of the routine maintenance procedures that require top
removal, including: inspection of the heat exchanger area,
coil inspection and cleaning, emd condensate drain pan
inspection and cleaning.
Only qualified service personnel should perform mainte­
nance and service procedures that require unit top removal.
Refer to the following top removal procedures:
1. Turn off gas supply, then turn off electric power to
unit.
2. Remove all screws that secure unit top, including
screws euound four sides and those on top that screw
into internal divider panels. Save all screws.
3. Tape all side panels at each seam near unit top. Use
tape strips that are at least 5-ins. long to prevent sides
from falling when top is removed.
4. Lift top from unit carefully. Set top on edge and ensure
that top is supported by unit side that is opposite duct
(or plenum) side. Use extreme care to prevent damage
to the fan blades, motor, and insulation.
5. Carefully replace and secure unit top to unit, using
screws removed in step 3, when maintenance and/or
service procedures are concluded. (Be sure to use origi­
nal screws that have rubber washers to seal out water
when securing top to internal divider panels.)
C. Evaporator Blower and Motor
For longer life, operating economy, and continuing efl&-
ciency; clean accumulated dirt and grease from the blower
wheel and motor annually.
Lubricate the motor every 5 years if the motor is used inter­
mittently (thermostat FAN switch in AUTO position), or
every 2 yeeus if the motor is used continuously (thermostat
FAN switch in ON position).
A WARNING
Turn off the gas supply, then disconnect and tag electri­
cal power to the unit before cleaning and lubricating the
blower motor and wheel. Failure to adhere to this warn­
ing could cause personal injury or death.
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