What causes a chiller to trip?

Low pressure trip — Caused by low refrigerant, power assembly broken capillary; low or no water flow; clogged water filter or screen; antifreeze or mud coating the tubes of the evaporator causing poor efficiency.

What is oil differential pressure in chiller?

The oil pressure differential switch breaks the control circuit and shuts down the compressor when the pressure difference between the oil pump outlet and the crankcase is too low. If the oil differential pressure drops below the minimum acceptable value the compressor will be stopped after a 120 seconds delay.

What is the purpose of an oil return system for a chiller?

An oil return pipe is available from the oil sump to the suction side of the screw. Because of the pressure difference from discharge to suction, the oil naturally lubricates the compressor without any need of an oil pump. The oil lubricates the bearings and is injected with the refrigerant along the screw.

What is chiller troubleshooting?

Chiller Troubleshooting: Common Problems Pumps can fail; process lines can clog; refrigerant can leak; any number of problems associated with component aging or changing environmental conditions may occur (Table I).

How is oil differential pressure calculated?

To find out, simply subtract the crankcase pressure from the oil pump discharge pressure to get net oil pressure. In this case, it would be 80 psi – 20 psi = 60 psi net oil pressure. This means the oil pump is actually putting 60 psi of pressure into the oil when delivering it into the crankshaft’s drilled passages.

How does oil return to the compressor?

Oil flows from the compressor with the discharge gas through the oil separator (if equipped and always less than 100\% efficient), and into the condenser. The liquid leaving the condenser consists mostly of refrigerant with some amount of dissolved oil (assuming that the oil is miscible in the refrigerant).

How should refrigerant be transferred from a chiller?

How should refrigerant be transferred from a chiller? Always begin the refrigerant transfer from a chiller unit using liquid recovery methods. What could happen if you charge liquid refrigerant into a chiller that is under a deep vacuum?

What causes high oil pressure in a refrigeration compressor?

Oil pressure trips can be caused by electrical problems. An electrical problem that causes the motor windings inside the compressor to overheat can cause internal overload in the compressor to open.