Pressure Switches; Loss Of Charge Switch; High Pressure Switch; Copeland Scroll Compressor (Puron Refrigerant) - Carrier Performance 50VT-A24 Installation Instructions Manual

Fig. 20 - - Refrigerant Circuit
Compressor
Access Panel
Fig. 21 - - Unit Access Panels
Step 8 — 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
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.
Step 9 — 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. 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 ohm meter leads across switch. You should have
continuity on a good switch.
C99097
Control
Blower
Access
Access
Panel
Panel
A09214
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.
Step 10 — 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.
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 ohm meter leads across switch. You should have
continuity on a good switch.
Step 11 — 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.
WARNING
!
EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Wear safety glasses and gloves when handling refrigerants.
Keep torches and other ignition sources away from refrigerant
and oils.
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 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 and 625 psi differential
pressure.
Step 12 — Refrigerant System
This step covers the refrigerant system of the 50VT- -A, including
the compressor oil needed, servicing systems on roofs containing
synthetic materials, the filter drier and refrigerant charging.
Refrigerant
WARNING
!
PROPERTY HAZARD, PERSONAL INJURY OR
ENVIRONMENTAL HAZARD
Failure to follow this warning could result in property damage
or personal injury or death.
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.
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