Carrier 50VL---A - Manual (Page 26)

26
each electrical component with the proper electrical
instrumentation. Refer to the unit wiring label when making these
checkouts.
NOTE: Refer to the heating and/or cooling sequence of operation
in this publication as an aid in determining proper control
operation
Refrigerant Circuit
Inspect all refrigerant tubing connections and the unit base for oil
accumulations annually. Detecting oil generally indicates a
refrigerant leak.
EXPLOSION, SAFETY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could result in personal
injury, death or equipment damage.
This system uses Puron (R--410A) refrigerant which has
higher operating pressures than R--22 and other refrigerants.
No other refrigerant may be used in this system. Gauge set,
hoses, and recovery system must be designed to handle
Puron. If you are unsure, consult the equipment
manufacturer.
WARNING
!
If oil is detected or if low cooling performance is suspected,
leak--test all refrigerant tubing using an electronic leak--detector,
halide torch, or liquid--soap solution. If a refrigerant leak is
detected, refer to Check for Refrigerant Leaks section.
If no refrigerant leaks are found and low cooling performance is
suspected, refer to Checking and Adjusting Refrigerant Charge
section.
Evaporator Airflow
The heating and/or cooling air--flow does not require checking
unless improper performance is suspected. If a problem exists, be
sure that all supply-- and return--air grilles are open and free from
obstructions, and that the air filter is clean. When necessary, refer to
Indoor Airflow and Airflow Adjustments section to check the
system airflow.
Puron Items
The indoor metering device is a TXV type device.
Pressure Switches
Pressure switches are protective devices wired into the control
circuit (low voltage). They shut off compressor if abnormally high
or low pressures are present in the refrigeration circuit. These
pressure switches are specifically designed to operate with Puron
(R--410A) systems. R--22 pressure switches must not be used as
replacements for the Puron (R--410A) air conditioner.
Loss of Charge/Low--Pressure Switch (Air Conditioner
Only)
This switch is located on the liquid line and protects against low
suction pressures caused by such events as loss of charge, low
airflow across indoor coil, dirty filters, etc. It opens on a pressure
drop at about 20 psig (957 Pa). If system pressure is above this,
switch should be closed.
To check switch:
1. Turn off all power to unit.
2. Disconnect leads on switch.
3. Apply ohmmeter leads across switch. You should have
continuity on a good switch.
NOTE: Because these switches are attached to refrigeration
system under pressure, it is not advisable to remove this device for
troubleshooting unless you are reasonably certain that a problem
exists. If switch must be removed, remove and recover all system
charge so that pressure gauges read 0 psi (0 Pa). Never open system
without breaking vacuum with dry nitrogen.
High--Pressure Switch
The high--pressure switch is located in the discharge line and
protects against excessive condenser coil pressure. It opens at 650
psig (31.1 kPa). High pressure may be caused by a dirty condenser
coil, failed fan motor, or condenser air recirculation.
To check switch:
1. Turn off all power to unit.
2. Disconnect leads on switch.
3. Apply ohmmeter leads across switch. You should have
continuity on a good switch.
Copeland Scroll Compressor (Puron Refrigerant)
The compressor used in this product is specifically designed to
operate with Puron (R--410A) refrigerant and cannot be
interchanged.
The compressor is an electrical (as well as mechanical) device.
Exercise extreme caution when working near compressors. Power
should be shut off, if possible, for most troubleshooting techniques.
Refrigerants present additional safety hazards.
FIRE/EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury or death and/or property damage.
Wear safety glasses and gloves when handling refrigerants.
Keep torches and other ignition sources away from
refrigerants and oils.
! WARNING
The scroll compressor pumps refrigerant throughout the system by
the interaction of a stationary and an orbiting scroll. The scroll
compressor has no dynamic suction or discharge valves, and it is
more tolerant of stresses caused by debris, liquid slugging, and
flooded starts. The compressor is equipped with a noise reducing
shutdown device and an internal pressure relief port. The pressure
relief port is a safety device, designed to protect against extreme
high pressure. The relief port has an operating range between 550
(26.3 kPa) and 625 (29.9 kPa) psig differential pressure.
Refrigerant
EXPLOSION, ENVIRONMENTAL HAZARD
Failure to follow this warning could result in personal
injury, death or equipment damage.
This system uses Puron (R--410A) refrigerant which has
higher operating pressures than R--22 and other refrigerants.
No other refrigerant may be used in this system. Gauge set,
hoses, and recovery system must be designed to handle
Puron. If you are unsure, consult the equipment
manufacturer.
WARNING
!
This system uses Puron (R--410A) refrigerant which has higher
operating pressures than R--22 and other refrigerants. No other
refrigerant may be used in this system. Gage set, hoses, and
recovery system must be designed to handle Puron. If you are
unsure, consult the equipment manufacturer. Failure to use Puron
compatible servicing equipment or replacement components may
result in property damage or injury.
Compressor Oil
The Copeland scroll compressor uses 3MAF POE oil. If additional
oil is needed, use Uniqema RL32--3MAF. If this oil is not
available, use Copeland Ultra 32 CC or Mobil Arctic EAL22 CC.
This oil is extremely hygroscopic, meaning it absorbs water
50V
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