Page 331 - Reciprocating Compressors Operation Maintenance

316 Reciprocating Compressors: Operation and Maintenance

Unit Blows Fuse

1. Fuses too small
2. Voltage is low
3. Pressure switch differential setting too close
4. Pressure switch release valve not operating (unit therefore starts
against load)
5. Motor bearings beginning to seize
6. Motor leads loose
7. Motor leads too small

Motor Overheats

1. Pressure switch differential setting too close, causing compressor to
cycle, resulting in excessively frequent starts
2. Voltage is low
3. Discharge pressure too high
4. Compressor running faster than rated
5. Motor needs cleaning
6. Motor bearings beginning to seize
7. Check belt or coupling alignment

Unit Will Not Start

1. Pressure switch contacts not mating
2. Worn contacts
3. Motor seized
4. Thermal overloads require resetting
5. Fuses blown

Intercooler Safety Valve Blows When Compressor Unloaded—
Second Stage Not Operating

1. Broken high pressure suction or discharge valve
2. Seat leaking on high pressure unloader piston
3. Broken unloader power spring
4. Unloader power piston stuck