Condenser Fans And Motors; Return-Air Filters; Outdoor- -Air Inlet Screens; Accessory Installation - Carrier 48LC 04 Controls, Start-Up, Operation And Troubleshooting

For belt drive units with a power exhaust option, the controls
require an accurate supply duct CFM at the unit design point
where the indoor fan will run at the Supply Fan Maximum
Speed (FS.MX) for proper operation. The supply duct CFM is
configured by the Indoor
(Configuration ECON IDF.C). Default values for Indoor
 
Fan Max Speed CFM (IDF.C) are at 400 CFM per ton
(1200CFM for the 04 size,1600 CFM for the 05 size, and 2000
CFM for the 06 size). It is preferred to use the supply duct CFM
from an air balance report to configure the Indoor Fan Max
Speed CFM (IDF.C). If an air balance report is not available,
then use the fan tables to determine Fan Max Speed CFM
(IDF.C). When using the fan tables to determine Fan Max Speed
CFM (IDF.C) set Economizer
Test INDP ECON) to 0 (Economizer Damper Closed) and
 
Indoor Fan Speed Test (Service Test
Supply Fan Maximum Speed (FS.MX). Measure the supply to
return duct static pressure difference and indoor fan RPM. Make
correction to static pressure for all options installed in the unit
per the accessory pressure drop table. Determine Indoor Fan
Max Speed CFM (IDF.C) on the fan table where the corrected
static pressure and RPM cross.

Condenser Fans and Motors

Condenser fans and motors are factory set.
Return- -Air Filters
Check that correct filters are installed in filter tracks (see Physical
Data table in Installation Instructions). Do not operate unit without

return-air filters.

Fig. 4 - - 48/50LC SRT Units, Panel and Filter Locations (48LC*06 Unit Shown)
Fan Max Speed CFM
Position Test (Service
FANS F.SPD) equal to
 
CONTROL BOX
ACCESS PANEL
GAS SECTION
ACCESS PANEL
UNIT FRONT

Outdoor- -Air Inlet Screens

Outdoor-air inlet screens must be in place before operating unit.

Accessory Installation

Check to make sure that all accessories including space thermostats
and sensors have been installed and wired as required by the
instructions and unit wiring diagrams.

Orifice Change (48LC)

This unit is factory assembled for heating operation using natural
gas at an elevation from sea level to 2000 ft.
Use accessory high altitude kit when installing this unit at an
elevation of 2000 to 7000 ft. For elevations above 7000 ft, refer to
High Altitude section to identify the correct orifice size for the
elevation. Purchase these orifices from your local Carrier dealer.
Follow instructions in accessory Installation Instructions to install
the correct orifices.
Use accessory LP (liquid propane) gas conversion kit when
converting this unit for use with LP fuel usage for elevations up to
7000 ft. For elevations above 7000 ft, refer to High Altitude
section to identify the correct orifice size for the elevation.
Purchase these orifices from your local Carrier dealer. Follow
instructions in accessory Installation Instructions to install the
correct orifices.
INDOOR
BLOWER
ACCESS
PANEL
FILTER
ACCESS PANEL
7
INDOOR COIL
ACCESS PANEL
UNIT BACK
C12218