System information

23
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 air flow across indoor coil, dirty filters, etc. It opens on a
pressure drop at about 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 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 kPa.
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
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 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.
WARNING: Wear safety glasses and gloves when handling
refrigerants. Keep torches and other ignition sources away
from refrigerants 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 pressure relief port is a safety
device, designed to protect against extreme high pressure. The
relief port has an operating range between 3792 and 4309 kPa
differential pressure.
The information below covers the refrigerant system of the
50JZ, including the compressor oil needed, servicing systems
on roofs containing synthetic materials, the filter drier and
refrigerant charging.
The Copeland scroll compressor uses Mobil 3MA POE oil.
This is the only oil allowed for oil recharge.
Refrigerant
CAUTION: This system uses Puron (R-410A) refrigerant which
has higher operating pressures than R-22 and other refrige-
rants. 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 replace-
ment 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 materials
POE (polyolester) compressor lubricants are known to cause
long-term damage to some synthetic roofing materials. Exposure,
even if immediately cleaned up, may cause embrittlement (lead-
ing to cracking) to occur in one year or more. When performing
any service that may risk exposure of compressor oil to the roof,
take appropriate precautions to protect roofing. Procedures that
risk oil leakage include, but are not limited to, compressor
replacement, repairing refrigerant leaks, replacing refrigerant
components such as filter drier, pressure switch, metering
device, coil, accumulator, or reversing valve.
Synthetic roof precautionary procedure
1. Cover extended roof working area with an impermeable
polyethylene (plastic) drip cloth or tarp. Cover an approxi-
mate 3 x 3 m area.
2. Cover area in front of the unit service panel with a towel
to absorb lubricant spills and prevent run-offs, and protect
drop cloth from tears caused by tools or components.
3. Place towel inside unit immediately under component(s)
to be serviced and prevent lubricant run-offs through the
louvered openings in the unit base.
4. Perform required service.
5. Remove and dispose of any oil contaminated material per
local codes.
Liquid line filter drier
The bi-flow filter drier is specifically designed to operate with
Puron. Use only factory-authorised replacement components.
Filter drier must be replaced whenever the refrigerant system is
opened. When removing a filter drier, use a tubing cutter to cut
the drier from the system. Do not unsweat a filter drier from
the system. Heat from unsweating will release moisture and
contaminants from drier into system.
Puron (R-410A) refrigerant charging
Refer to unit information plate and charging chart. Some R-410A
refrigerant cylinders contain a dip tube to allow liquid refrige-
rant to flow from cylinder in upright position. For cylinders
equipped with a dip tube, charge Puron units with cylinder in
upright position and a commercial metering device in manifold
hose. Charge refrigerant into suction line.
Refrigeration service ports
Each unit system has 3 Schrader-type service ports: one on the
suction line, one on the liquid line, and one on the compressor
discharge line. Be sure that caps on the ports are tight.