Refrigerant Circuit; Indoor Airflow; Puron® Systems Items - Carrier 50JZ Installation, Start-Up And Service Instructions Manual

screw connections. If any smoky or burned connections are
noticed, disassemble the connection, clean all the parts, restrip the
wire end and reassemble the connection properly and securely.
After inspecting the electrical controls and wiring, replace all the
panels. Start the unit, and observe at least one complete cooling
cycle to ensure proper operation. If discrepancies are observed in
operating cycle, or if a suspected malfunction has occurred, check
each electrical component with the proper electrical instrumenta-
tion. Refer to the unit wiring label when making these checkouts.
Step 6—Refrigerant Circuit
Inspect all refrigerant tubing connections and the unit base for oil
accumulation annually. Detecting oil generally indicates a refrig-
erant 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.
Step 7—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.
Step 8—PURON® Systems Items
The Following items should be taken into consideration when
maintaining your Puron® System.
Metering Devices–Accurater Piston
This metering 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 devices wired into control circuit
(low voltage). They shut off compressor if abnormally high or low
pressures are present in the refrigeration circuit. These pressure
Fig. 24—Refrigerant Circuit
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 Switch
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 (138 kpa). If system pressure is above this,
switch should be closed. To check switch:
1. Turn off all power to unit and install lockout tag..
2. Disconnect leads on switch.
3. Apply ohm meter 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. 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 610
psig (4205 kpa). 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 and install lockout tag.
2. Disconnect leads on switch.
3. Apply ohm meter 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 inter-
changed.
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.
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