Service manual

Maintenance Service and Trouble Shooting

many joints and sealed surfaces in a

There are so

refrigerator ,accordingly ,quite a lot potential leak points do exist in the system .In

troubleshooting, pay attention to those parts that are liable to leak ,check main connection

points for oil seepage and tubing for cracks .If there is no severer leak point, charge the

system with nitrogen and detect leak points with the commonly adopted method, repair

them, evacuate ,charge the system with refrigerant ,and then turn on the refrigerator to

make a test run.

2) Too much refrigerant charged into the system

Analysis of Trouble

a) In case the amount of refrigerant charged into the system exceeds

its nominal capacity ,the superfluous refrigerant will of course take some

space of the evaporator ,thus reducing its heat-dissipation area and hence

the refrigerating efficiency of the system .The abnormal phenomena

caused by this reason are as follows :the gas suction and exhaust

pressures are generally higher than their respective normal values ,the

temperature of its condenser is higher and the electric current of the

compressor rises ,loose frost forms on the evaporator ,the refrigerator

temperature drops slowly ,and frost appears on the gas return tube.

b) In case excessive refrigerant has been charged, the liquid refrigerant that cannot

evaporates in the evaporator will return to the compressor ,and thus a phenomenon of

"liquid striking" will occur .The

liquid refrigerant evaporates and effervesces as soon as it flows into the

refrigerating oil at the bottom of compressor .If the condition is severe ,foams will fill all

over inside the compressor housing and be sucked by the piston, causing damage to the

components of compressor .

Remedy

According to the operating procedures, it is mandatory to turn the machine off, and

several minutes later ,open the refrigerant charging tube and et the refrigerant escape

from it ,replace the dry filter, recharge refrigerant after evacuating ,and then seal the

charging port .

3) There is air left in the refrigerating system

Analysis of Trouble

Residual air in the refrigerating system will reduce its refrigerating efficiency .The

prominent phenomena are the increase in its gas suction

and exhaust pressures (however ,the gas exhaust pressure will not exceed

its rated value ),obvious increase in temperature in the segment from the

compressor outlet to the condenser inlet .Because there is air in the

system ,both the gas exhaust pressure and temperature will rise ,and

moreover ,the gas flowing sound is intermittent and obviously louder .

Remedy

After shut down for several minutes ,open the tubing ,evacuate it and

then recharge the system with refrigerant .

4) Low efficiency of compressor