47 - Trouble shooting -
TROUBLE SHOOTING
No.
symptom possible causes
1
Pump does not run
No power connectiom
Differential pressure switch has been activated
Damaged coupling
1a
Pump does not prime
valve in the vent line not open
vent line not individually piped to the low pressure side
foreign material in pump
2
pump makes scratching noise
lack of refrigerant
conical filter is blocked
too fast decrease of the evaporating temperature
impellers or intermediate pieces worn out
bearings worn out
a too big pump has been selected
operation at maximum pressure of the pump
direction of rotation wrong
3
capacity too low
frequency of the pump too low
stop valves behind the pumps closed
too much gas in liquid
liquid level in separator too low
valves on cooler closed
regulating valve not opened far enough
contamination is blocking the piping system
non return valve of an other pump leakes
power supply not right, working on only 2 phases
impellers worn out
oil in pump at low temperature
not sufficient suction head
Intermediate pieces do not align (see 9.4, fig 14+15)
see number 2
4
switched off on pressure difference control
set value of pressure control not right
hand control valves in system opened too much
too quick start up or capacity steps of compressor(s)
too quick switch off of big capacities
see number 2
5
switched off on flow switch
set value of flow switch not right
suction side or discharge side closed
too quick start up or capacity steps of compressor(s)
too quick switch off of big capacities
6
Oil leakage on the motor side Outer shaft seal needs to be replaced
7
Damaged shaft seal
Lack of refrigerant
Contamination in the system, felt rings are not in place
Insufficient liquid head (see chapter 6.3)
No or wrong oil filling
Hand wheel (85) was closed
Seal sticks to the shaft after a long stand-still(see 8.7)
8
life time of bearings too short
see also above points for damaged shaft seal
too much dirt in system, e.g. small particles
Set too low
9
Motor protection/fuses trip the pump
Pump is blocked (see above)
Improper oil filling (too high viscosity)
Damaged motor
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