SERVICING OF EXPANSION VALVE OF REFRIGERATION UNIT

1.0 PURPOSE:
    
    To  describe a  standard operating procedure for  servicing  of  expansion valve of refrigeration unit. 
    
2.0    SCOPE:
    
    The standard operating procedure describes in detail the method  for servicing of expansion valve of refrigeration unit.
    
3.0    RESPONSIBILITY:
    
    The responsibility of servicing of expansion valve of refrigeration  unit  lies  with the staff of rank not  lower  than  the  junior utility operator. 
        
The  responsibility of preparing, reviewing  and approving  the  standard  operating  procedure lies with the  Manager  -  Maintenance,  Head of Production and Head of QAD respectively.        
    
4.0    METHOD:
    
4.1        Start the compressor.
    
4.2        Pump down the compressor as per SOP CHANGING/ADDITION OF OIL OF  REFRIGERATION UNIT.from 4.1  to  4.7.
    
4.3        Loosen  the  throttle valve of the expansion valve  and  slowly  remove it.
    
4.4        Remove spring and injector.
    
4.5        Loosen  and  remove the clamp of power element  bulb  which  is  fixed to the return gas line of the chiller.
    
4.6        Remove the bulb from the clamp.
    
4.7       Using 30/36 double end  spanner slowly remove the power element  from the expansion valve.
    
4.8        Loosen  and remove the bolts provided for the fixing of  expansion valve to the chiller.
    
4.9        Slowly remove the expansion valve from its position.

4.10       Clean the holes of the valve using an alpine or binding wire.

4.11       Replace  the defective power element assembly with new one.

4.12       Fix the expansion valve unit to the chiller and liquid line.

4.13       Fix  the power element assembly to the expansion valve and  the   assembly bulb to the return gas line of the chiller.

4.14       Place the injector, spring and spring support in the  expansion  valve and fix the throttle valve of the expansion valve.

4.15       Open all the valves of the compressor viz., liquid line valves,  discharge gun valve and suction gun valve.

4.16       Carry out leak testing with soap solution.

4.17       Rectify the leaks of expansion valve by tightening.

5.0        RECORDING:

    The  responsibility of recording the breakdown  in the  history  card   lies with the staff of rank not lower than  the  maintenance supervisor. 

Refrigeration unit, engineering, liquid line