Bitzer 4UFC

24
KW-540-1
suction pressure too low
• faulty TX valve function
• insufficient refrigerant charge
• insufficient evaporator capacity
• excessive oil in evaporator
• Suction filter blocked or throttling in suction
shut-off valve, liquid or suction line
suction / condensing pressure too high
• insufficient condenser capacity
• too much refrigerant
• foreign gas
• discharge shut-off valve throttled
• check valve in discharge line defective or too small size
discharge gas / oil temperature too high
• insufficient refrigerant
• by-pass between high and low pressure
• inert gas
defective / leaking working valves
• valve / gasket bridge broken
• contamination (oil coke / foreign particles)
leaking cylinder head gasket
• check function and superheat setting
• check system for leaks, charge to minimum level
• clean, if iced-up cure the cause, check fan
• reduce oil charge
• cure cause, possibly change filter
• clean, check fan
• reduce to minimum level
• purge (see operating instruction)
• open fully
• exchange
(discharge gas: max. 120°C on outside of discharge line,
oil: max. 80°C outside on crankcase (cleaned surface))
• check system for leaks, charge to minimum level
• check / exchange relief valve, check plant
• purge (see operating instruction)
• repair, cure cause.
Valve damage mainly caused by liquid slugging due to
excessive refrigerant, too much oil or faulty TX valve regula-
tion; with discharge valve breakage danger of damage to
connecting rod bearing)
• clean / exchange, cure cause.
Oil coke mainly due to excessive operating temperature or
inert gas
• exchange (do not oil asbestos free gaskets!)
Safety cut-out (Compressor cuts out due to LP/HP pressure switch or discharge gas sensor)
Possible reasons Measures, recommendations
Insufficient capacity (Compressor provides too little refrigeration capacity)
suction pressure too low
insufficient pressure generation
• defective / leaking working valves
• worn piston rings / cylinder liners
• leaking cylinder head gasket
• by-pass between high and low pressure
• capacity control sticking
abnormal operating conditions
• too low / too high superheat
• application limits exceeded
• inert gas
• too much / too little refrigerant
• too much oil
• see “safety cut-out”
• see “safety cut-out”
• exchange of connecting rods/pistons and liners
• exchange (do not oil asbestos free gaskets!)
• check / exchange internal relief valve, check plant
• repair / exchange
• see “safety cut-out”
• see “safety cut-out”
• purge (see operating instruction)
• charge / reduce to minimum level
• reduce quantity of oil