Heatcraft Refrigeration Products H-IM-79E Manual De Usuario

All evaporator units should be checked once a month 

or more often for proper defrosting because the amount 

and pattern of frosting can vary greatly. It is dependent 

on the coil temperature, the temperature of the room, 

the type of product being stored, how often new product 

is brought into the room and the percentage of time 

the door to the room is open. It may be necessary to 

periodically change the number of defrost cycles or 

adjust the duration of defrost. 

 

Under normal usage conditions, maintenance should 

cover the following items at least once every 6 months:
  1.  Check and tighten ALL electrical connections
  2.  Check all wiring and insulators
  3.  Check contactors for proper operation and for  

 

    worn contact points

  4.  Check all fan motors. Tighten motor mount bolts    

  and nuts and tighten fan set screws

  5.  Clean the condenser coil surface
  6.  Check the refrigerant and oil level in the system
  7.  Check the operation of the control system. Make  

  certain all safety controls are operating properly

After the installation has been completed, the following points 
should be covered before the system is placed in operation:
 

(a)  Check all electrical and refrigerant connections.  

 

  Be sure they are all correct and tight.

 

(b)  Check voltage taps on transformer. The transformer is  

 

  shipped wired to 240 voltage tap/connection. If your  

 

  supply voltage is 208 volt systems, change to 208  

 

  voltage tap.

 

(c)  Check setting of time delay relay for low pressure switch  

 

  in condensing unit. It should be set at one minutes  

 

  (the second marker).

 

(d)  Check high and low pressure controls, pressure  

 

  regulating valves, oil pressure safety controls, and all  

 

  other safety controls and adjust them, if necessary.

 

(e)  On freezers only, check the low pressure switch setting.  

 

  It must be set to 0 PSIG cut out, 10 PSIG cut in, to allow  

 

  start and operation, especially in cold ambients.

 

(f)   Liquid line should always be insulated.

 

(g)  Wiring diagrams, instruction bulletins, etc. attached to  

 

  the condensing units should be read and filed for future  

 

  reference.

 

(h)  All fan motors on air cooled condensers, evaporators,  

 

  etc. should be checked for proper rotation. Fan motor  

 

  mounts should be carefully checked for tightness and  

 

  proper alignment. 

  8.  Check that all defrost controls are functioning 

  properly

  9.  Clean the evaporator coil surface
  10.  Clean the drain pan and check the drain pan and  

  drain line for proper drainage

  11.  Check the drain line heater for proper operation, 

  cuts and abrasions

  12.  Check and tighten all flare connections

 

(i)  Observe system pressures during charging and initial  

 

  operation. Do not add oil while the system is short of  

 

  refrigerant unless oil level is dangerously low.

 

(j)  Continue charging until system has sufficient refrigerant  

 

  for proper operation. Do not overcharge. Remember that  

 

  bubbles in a sight glass may be caused by a restriction  

 

  as well as a shortage of refrigerant.

 

(k)  Do not leave unit unattended until the system has  

 

  reached normal operating conditions and the oil charge  

 

  has been properly adjusted to maintain the oil level at  

 

  the center of the sight glass. 

 

(l)   At initial start-up, the system may cycle off at 2 minutes  

 

  and display a low superheat error, then restart itself. This  

 

  cycle may be repeated a few times. Do not shut the  

 

  system off. Let the system run, as it may take a few  

 

  cycles for the electric expansion valve to attain the  

 

  correct setting for the desired superheat. 

 

CAUTION: Extreme care must be taken in starting 

compressors for the first time after system charging. At 
this time, all of the oil and most of the refrigerant might be 
in the compressor creating a condition which could cause 
compressor damage due to slugging. Activating the crankcase 
heater for 24 hours prior to start-up is recommended. If no 
crankcase heater is present, then directing a 500 watt heat 
lamp or other safe heat source on the lower shell of the 
compressor for approximately thirty minutes will be beneficial 
in eliminating this condition which might never reoccur.