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
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.
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 psig. Never open system without breaking vacuum with dry nitrogen.
Step 10 — High-Pressure Switch
The
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
!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 psig differential pressure.
Step 12 — Refrigerant System
This step covers the refrigerant system of the
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
Compressor Oil
The Copeland scroll compressor uses 3MAF POE oil. If additional oil is needed, use Uniqema
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 (leading 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 which 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 approximate 10x10 ft (3x3 m) area.
2.Cover area in front of the unit service panel with a terry cloth shop towel to absorb lubricant spills and prevent
3.Place terry cloth shop towel inside unit immediately under component(s) to be serviced and prevent lubricant
4.Perform required service.
5.Remove and dispose of any oil contaminated material per local codes.
Liquid Line Filter Drier
The biflow filter drier is specifically designed to operate with Puron. Use only
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