Unit Operation
Before starting the unit, ensure the following:
• All the electrical connections are correct and as per the recommended wiring diagrams
• All low side tubings are properly insulated
• Leak check is done and unit is pre-charged with refrigerant through high side
• Check for superheat setting on the expansion valve (TXV) appropriate or not
14
• Do not use compressor to pull vacuum
• Never use the compressor to suck oil into the system
• Do not test compressor by closing suction valve
• Do not set low pressure switch below 0 bar
• Do not bypass LP controls
• Do not pump down below 0 bar
• Reverse Rotation
- Incorrect rotation can be identified by:
Low current, noise, balanced suction, and discharge pressure;
- Correct by interchanging any two phases
- Short-term reverse rotation will not damage the compressor
Application tips for scroll compressors
Approved compressor oil
POE-32: Polyolester Oil (Copeland Ultra 32-3MAF, Lubrizol Emkarate RL32-3MAF, Everest
32-3MAF, National NL PE32-3MAF, Parker EMKARATE RL32-3MAF/ (Virginia) LE323MAF, Nu Calgon
4314-66/EMKARATE RL32-3MAF, Everest 22 CC, Copeland Ultra 22 CC, Mobil Arctic 22 CC). Last
three are approved for ‘top off’ only, 32-3MAF preferred.
Model Control type R-404A/507 R-134A
R-22 / R-407A / R-407C /
R407F / R-448A / R-449A
ZF* K5E
Low
High
0 psig min.
400 psig min.
2 in. Hg Min.
335 psig Max.
ZB*K5E
Low
High
17 psig min.
450 psig max
4 psig min.
263 psig max
37 psig min.
381 psig max
High and low pressure control settings
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Adding refrigerant on a cold weather results to an overcharged unit, which may then trip out on high
pressure limit during warm weather.
Suction Superheat should be 10–15 K for reliable operation.
Remember that the refrigerant is under pressure. Always wear protective equipment, i.e. safety
glasses or goggles and gloves when working with refrigerant, and guard against refrigerant spray-ing into
the face or skin. Line pressures on an operating conditioning unit will vary with outdoor temperatures. As
outdoor temperatures rise, pressures will also rise.
Caution
DO NOT, UNDER ANY CIRCUMSTANCES, HEAT THE REFRIGERANT CYLINDER WITH A TORCH OR BY ANY
OTHER MEANS OTHER THAN WARM WATER. EXCESSIVE PRESSURES GENERATED IN THIS MANNER MAY
WEAKEN THE REFRIGERANT CONTAINER AND RESULT TO A CYLINDER EXPLOSION!
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