Friedrich kuhl r-410a ユーザーズマニュアル

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Proper refrigerant charge is essential to proper unit operation. 
Operating a unit with an improper refrigerant charge will 
result in reduced performance (capacity) and/or effi ciency. 
Accordingly, the use of proper charging methods during 
servicing will insure that the unit is functioning as designed 
and that its compressor will not be damaged. 

Too much refrigerant (overcharge) in the system is just as bad 
(if not worse) than not enough refrigerant (undercharge). They 
both can be the source of certain compressor failures if they 
remain uncorrected for any period of time. Quite often, other 
problems (such as low air fl ow across evaporator, etc.) are 
misdiagnosed as refrigerant charge problems. The refrigerant 
circuit diagnosis chart will assist you in properly diagnosing 
these systems. 

An overcharged unit will at times return liquid refrigerant 
(slugging) back to the suction side of the compressor eventually 
causing a mechanical failure within the compressor. This 
mechanical failure can manifest itself as valve failure, bearing 
failure, and/or other mechanical failure. The specifi c type of 
failure will be infl uenced by the amount of liquid being returned, 
and the length of time the slugging continues. 

Not enough refrigerant (undercharge) on the other hand,  will 
cause the temperature of the suction gas to increase  to the point 
where it does not provide suffi cient cooling for  the compressor 
motor. When this occurs, the motor winding temperature will 
increase causing the motor to overheat  and possibly cycle open 
the compressor overload protector.  Continued overheating of 
the motor windings and/or cycling of the overload will eventually 
lead to compressor motor or overload failure. 

Sealed Refrigeration System contains refrigerant 

and oil under high pressure.

Proper safety procedures must be followed, 

and proper protective clothing must be worn 

when working with refrigerants.

Failure to follow these procedures could 

result in serious injury or death. 

Unplug and/or disconnect all electrical power 

to the unit before performing inspections, 

maintenances or service. 

Failure to do so could result in electric shock, 
serious injury or death.

SEALED SYSTEM REPAIRS TO COOL-ONLY MODELS REQUIRE THE INSTALLATION OF A LIQUID LINE DRIER. 

 1.  Voltmeter

 2.  Ammeter

 3.  Ohmmeter

  4.   E.P.A. Approved Refrigerant Recovery System

 5.  Vacuum Pump (capable of 200 microns or less 

vacuum.)

 6.  Acetylene Welder

 7.  Electronic Halogen Leak Detector capable of 

detecting HFC (Hydrofl uorocarbon) refrigerants.

  8.  Accurate refrigerant charge measuring device such 

as:

    a.  Balance Scales - 1/2 oz. accuracy

    b.  Charging Board - 1/2 oz. accuracy

9.      High Pressure Gauge - (0 to 750 lbs.)

10.  Low Pressure Gauge - (-30 to 200 lbs.)

 11.  Vacuum Gauge - (0 - 1000 microns)

12.  Facilities for fl owing nitrogen through refrigeration tubing 

during all brazing processes.

  1.  Recovering refrigerant to EPA required levels.

  2.   Evacuation from both the high side and low side of the 

system simultaneously.

 3.  Introducing refrigerant charge into high side of the 

system.

  4.  Accurately weighing the refrigerant charge introduced 

into the system. 

Because the RAC system is a sealed system, service 

process tubes will have to be installed. First install a line tap 
and remove refrigerant from system. Make necessary sealed 
system repairs and vacuum system. Crimp process tube 
line and solder end shut. Do not leave a service valve in the 
sealed system.