Friedrich CP24N30 Manual Do Utilizador

10

NOTE:  In order to access the sealed system it will be necessary to install Schrader type fi ttings to the process tubes 
on the discharge and suction of the compressor. Proper refrigerant recovery procedures need to be adhered to as 
outlined in EPA Regulations. THIS SHOULD ONLY BE ATTEMPTED BY QUALIFIED SERVICE PERSONNEL.

Refrigerant Charging

NOTE: 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.

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.

The acceptable method for charging the RAC system is the 

Weighed in Charge Method.  The weighed in charge method is 
applicable to all units. It is the preferred method to use, as it is the 
most accurate.

The weighed in method should always be used whenever a charge 

is removed from a unit such as for a leak repair, compressor 
replacement, or when there is no refrigerant charge left in the unit. 

To charge by this method, requires the following steps:

1.  Install a piercing valve to remove refrigerant from the 

sealed system.  (Piercing valve must be removed from 

the system before recharging.)

2.  Recover Refrigerant in accordance with EPA 

regulations.

3.  Install a process tube to sealed system.

4.  Make necessary repairs to system.

5.  Evacuate system to 250 - 300 microns or less.

6.  Weigh in refrigerant with the property quantity of R-22 

refrigerant.

7. 

Start unit, and verify performance.

8.  Crimp the process tube and solder the end shut.