Lubrication; Refrigerant Feed Components; Electronic Expansion Valve (Exv); Refrigeration Circuits - Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

3. Start high pressure water sprayer and purge any soap or
industrial cleaners from sprayer before cleaning condens-
er coils. Only clean potable water is authorized for clean-
ing condenser coils.
4. Clean condenser face by spraying the core steady and
uniformly from top to bottom while directing the spray
straight toward the core. Do not exceed 900 psig or
30 degree angle. The nozzle must be at least 12 in. from
the core face. Reduce pressure and use caution to prevent
damage to air centers.
CAUTION
Excessive water pressure will fracture the braze between
air centers and refrigerant tubes.
CONDENSATE DRAIN — Check and clean each year at
start of cooling season. In winter, keep drains and traps dry.
FILTERS — Clean or replace at start of each heating and cool-
ing season, or more often if operating conditions require. Refer
to Installation Instructions for type and size.
1. Remove economizer outdoor-air filters from the hoods by
removing the filter retainers.
2. Clean filters with steam or hot water and mild detergent.
3. Reinstall filters in hoods after cleaning. Never replace
cleanable filters with throwaway filters.
OUTDOOR-AIR INLET SCREENS — Clean screens with
steam or hot water and a mild detergent. Do not use disposable
filters in place of screens.

Lubrication

FAN SHAFT BEARINGS — Lubricate fan shaft bearings at
least once a year with suitable bearing grease. Optional extend-
ed grease lines may be provided on pulley side of blower. Typ-
ical lubricants are given below:
MANUFACTURER
Texaco
Mobil
Sunoco
Texaco
*Preferred lubricant because it contains rust and oxidation inhibitors.
FAN MOTOR BEARINGS — The condenser-fan motors
have sealed bearings so no field lubrication is required.
DOOR HINGES — All door hinges should be lubricated at
least once a year.
Electronic Expansion Valve (EXV) —
has 2 EXVs on which superheat may be adjusted if necessary
by using the ComfortLink controller. Adjustment is not nor-
mally required or recommended.
The TXV is set to maintain 10 to 13 F superheat leaving the
evaporator coil. It controls the flow of refrigerant to the evapo-
rator coils.

Refrigeration Circuits

LEAK TESTING — Units are shipped with a full operating
charge of R-410A (see unit nameplate). If there is no pressure
in the system, introduce enough nitrogen to search for the leak.
Repair the leak using good refrigeration practices. After leaks
are repaired, system must be evacuated and dehydrated
LUBRICANT
Regal AFB-2*
Mobilplex EP No. 1
Prestige 42
Multifak 2
Each circuit
159
using methods described in GTAC II, Module 4, System
Dehydration.
REFRIGERANT CHARGE — Amount of refrigerant charge
is listed on unit nameplate. Refer to Carrier GTAC II; Module
5; Charging, Recovery, Recycling, and Reclamation section for
charging methods and procedures.
Unit panels must be in place when unit is operating during
charging procedure.
NOTE: Do not use recycled refrigerant as it may contain
contaminants.
NO CHARGE — Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of refriger-
ant from the unit nameplate.
LOW CHARGE COOLING — Due to the compact, all alu-
minum design, microchannel heat exchangers will reduce
refrigerant charge and overall operating weight. As a result,
charging procedures for MCHX units require more accurate
measurement techniques. Charge should be added in small
increments. Using cooling charging charts provided (Fig. 58-
79), add or remove refrigerant until conditions of the chart are
met. As conditions get close to the point on the chart, add or
remove charge in 1 / lb increments until complete. Ensure that
4
all fans are on and all compressors are running when using
charging charts.
To Use the Cooling Charging Chart — Use the outdoor air
temperature, saturated suction temperature (SST) and saturated
condensing temperature (available on the ComfortLink dis-
play), and find the intersection point on the cooling charging
chart. If intersection point is above the line, carefully recover
some of the refrigerant. If intersection point is below the line,
carefully add refrigerant.
NOTE: Indoor-air cfm must be within normal operating range
of unit.
Units With Humidi-MiZer® Adaptive Dehumidification
System
NOTE: All circuits must be running in normal cooling mode.
Indoor airflow must be within specified air quantity limits for
cooling. All outdoor fans must be on and running at normal
speed.
Use the following procedure to adjust charge on Circuit B
of Humidi-MiZer equipped units:
1. Start all compressors and outdoor fans. Allow unit to run
for 5-minutes.
2. Switch system to run in a Dehumidification mode for 5
minutes by switching RHV to ON through the Service
Test function (Service Test
3. At the end of the 5-minute period, switch back into Cool-
ing mode through the Service Test function (Service
 
Test COOL RHV) by switching RHV to OFF.
4. Using the cooling charging charts provided (Fig. 58-79),
add or remove refrigerant until conditions of the chart are
met. As conditions get close to the point on the chart, add
or remove charge in /
1
4
paragraph "To Use the Cooling Charging Chart" for addi-
tional instructions.
5. If a charge adjustment was necessary in Step 4, then re-
peat the steps in this paragraph (starting with Step 2) until
no charge adjustment is necessary. When no more charge
adjustment is necessary after switching from a Dehumidi-
fication Mode to a Cooling Mode (Steps 2 and 3), then
the charge adjustment procedure is complete.
 
COOL RHV).
lb increments until complete. See