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UNIT DAMAGE HAZARD
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 cooling season, or
more often if operating conditions require. Refer to Installation In-
structions 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 bear-
ing grease. If unit has been non-operational for more than six
months, grease should be added. Extended grease lines are provid-
ed on pulley side of blower. Typical lubricants are given below:
MANUFACTURER
Texaco
Mobil
Sunoco
Texaco
NOTE(S):
a. Preferred lubricant because it contains rust and oxidation inhibitors.
FAN MOTOR BEARINGS
The condenser-fan motors have sealed bearings, so no field lu-
brication is required. Fan motors with lubrication ports or fit-
tings must be lubricated after long periods of non-operation or at
periodic maintenance with the fan shaft bearings.
DOOR HINGES
All door hinges should be lubricated at least once a year.
Refrigerant Feed Components
Each refrigerant circuit (2 per unit) has all the necessary refriger-
ant controls.
CAUTION
LUBRICANT
Regal AFB-2
a
Mobilplex EP No. 1
Prestige 42
Multifak 2
Thermostatic Expansion Valve (TXV)
On sizes 030 and 035, each circuit has one TXV. On sizes 040-
100, each circuit has 2 TXVs on which superheat may be adjusted
if necessary. Adjustment is not normally required or
recommended.
The TXV is set to maintain 10°F to 13°F superheat leaving the
evaporator coil. It controls the flow of refrigerant to the evaporator
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 refriger-
ation practices. After leaks are repaired, system must be evacuated
and dehydrated 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 refrigerant from the unit name-
plate.
LOW CHARGE COOLING
Due to the compact, all aluminum design, microchannel heat ex-
changers 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. 56-93), add or remove refrigerant until conditions of the
chart are met. The charts and SCT, OAT and SST as read on the
controls must be used for MCHX charge checks or the low ambi-
ent controls may not perform correctly and there will be a loss of
efficiency. As conditions get close to the point on the chart, add or
remove charge in 1/4 lb increments until complete. Ensure that all
fans are on and all compressors are running when using charging
charts.
IMPORTANT: For units with standard ambient control (no
condenser fan VFD), ensure that all condenser fans and all
compressors are on when adjusting system refrigerant
charge using the charging charts.
For units with low ambient control or Greenspeed (condenser
fan VFD), ensure that all condenser fans are on and operating
at 100% speed and all compressors are on when adjusting sys-
tem charge using the charging charts.
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