Reciprocating compresor,grasso.sabroe,mycom,bitzer

Refrigeration compressor, troubleshooting for piston compressor grasso,mycom,sabroe,bitzer

A. High suction pressure
Occurs when the gas formation on the evaporator side exceeds the compressor pump capacity in the operating area in question. The reason may be due to the load on the evaporating side being larger than expected,or a mechanical fault in the compressor causing reduced pump capacity.
1. Excessive suction pressure
1.1. The compressor is short of capacity
1.2. Leaky suction valves
1.3. Open by-pass between suction and high pressure sides of the compressor. Leaky safety valve,or the safety valve opens to early.
1.4. Liquid regulator valve set incorrectly.
Remedy :
1.1. Regulate the compressor capacity. Check that all cylinders are working. Check to see if the capacity regulator is working correctly.
1.2. Remove the cylinder covers,then check the valve plates and piston rings.
1.3. Check to see if there is any by-pass in the system.
1.4. Liquid refrigerant in the suction line.Reset,repair or replace the regulating valve.

2. Low suction pressure
An abnormally low suction pressure causes the compression ratio to change,Which in turn many cause damage to the compressor. If there is low pressure in the system (vacuum) air may be drawn into the refrigeration plant.
Low suction pressure results in reduced compressor capacity.
Insufficient suction pressure
2.1. Excessive compressor capacity.
2.2. Insufficient refrigerant charge bubbles appear in the sight glass, an the liquid line may be warm.
2.3. Oil in the evaporator.
2.4. Clogged filter in the liquid line.
Remedy :
2.1. Reduce the compressor capacity.Check the capacityregulation system.
2.2. Check the refrigerant charge.Charge the plant with refrigerant.Locate the leak and repair it.
2.3. Check and clean the filter in the liquid line.