Carrier 50JZ024, Installation, Start-Up And Service Instructions Manual

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REFRIGERANT CIRCUIT — Inspect all refrigerant tubing con-
nections and the unit base for oil accumulation annually. Detecting
oil generally indicates a refrigerant leak.
If oil is detected or if low performance is suspected, leak-test all
refrigerant tubing using an electronic leak detector, 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 performance is suspected,
refer to Checking and Adjusting Refrigerant Charge section.
INDOOR AIRFLOW — The heating and/or cooling airflow 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.
METERING DEVICES—ACCURATER® PISTON — This me-
tering device is a fixed orifice and is contained in the brass
hex-body in the liquid line feeding the indoor and outdoor coils.
PRESSURE SWITCHES — Pressure switches are protective de-
vices wired into 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) system.
LOSS OF CHARGE/LOW-PRESSURE SWITCH (AIR CONDI-
TIONER 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. 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 ohmeter leads across switch. You should have conti-
nuity 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. Never open system
without breaking vacuum with dry nitrogen.
HIGH-PRESSURE SWITCH — The high-pressure switch is lo-
cated in the discharge line and protects against excessive con-
denser coil pressure. It opens at 610 psig.
High pressure may be caused by a dirty outdoor coil, failed fan
motor, or outdoor air recirculation.
To check switch:
1. Turn off all power to unit.
2. Disconnect leads on switch.
3. Apply ohmeter leads across switch. You should have conti-
nuity on a good switch.
COPELAND SCROLL COMPRESSOR (PURON REFRIGER-
ANT) — 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 tech-
niques. Refrigerants present additional safety hazards.
Wear safety glasses and gloves when handling refrigerants.
Keep torches and other ignition sources away from refriger-
ants and oils. Failure to follow this warning can cause a fire,
serious injury, or death.
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 an anti-rotational
device and an internal pressure relief port. The anti-rotational
device prevents the scroll from turning backwards and replaces the
need for a cycle protector. The pressure relief port is a safety
device, designed to protect against extreme high pressure. the
relief port has an operating range between 550 and 625 psi
differential pressure.
The Copeland scroll compressor uses Mobil 3MA POE oil.
This is the only oil allowed for oil recharge.
REFRIGERANT SYSTEM
REFRIGERANT
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.
Failure to use Puron compatible servicing equipment or
replacement components may result in property damage or
injury.
COMPRESSOR OIL — The compressor in this system uses a
polyolester (POE) oil, Mobil 3MA POE. This oil is extremely
hygroscopic, meaning it absorbs water readily. POE oils can
absorb 15 times as much water as other oils designed for HCFC
and CFC refrigerants. Take all necessary precautions to avoid
exposure of the oil to the atmosphere.
SERVICING SYSTEMS ON ROOFS WITH SYNTHETIC MA-
TERIALS — POE (polyolester) compressor lubricants are known
to cause long term damage to some synthetic roofing materials.
Fig. 30—Refrigerant Circuit
C99097
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