Section
5
Sealed System
5
-7
Low/High Side Leak or Undercharge
A loss of refrigerant can result in any of the following:
1. Excessive or continuous compressor operation.
2. Air from AC unit is not cold.
3. A partially frosted evaporator (depending on amount
of refrigerant loss).
4. Low suction pressure (vacuum).
5. Low wattage.
amount of refrigerant lost.
In the case of a low side refrigerant leak resulting in
complete loss of refrigerant, the compressor will run but
will not refrigerate. Suction pressure will drop below
atmospheric pressure and air and moisture will be drawn
into the system, saturating the filter drier. A system with
R-410A refrigerant will become saturated with moisture
much faster than a system with R-22. Therefore, you
must obtain a sample of the oil and check with an oil
test kit to determine the amount of contamination. You
will find that the oil in an R-410A system will have to be
replaced after most low side leaks.
If there is reason to believe the system has operated for
a considerable length of time with no refrigerant and the
leak occurred in the low side of the system, excessive
amounts of moisture may have entered the system.
The system will probably require a system flush and a
compressor replacement.
If a slight undercharge of refrigerant is indicated and no
leak can be found after a thorough leak test, the charge
can be corrected without changing the compressor.
to charge R-410A refrigerant into the low side of an
operating system.
If a high side leak is located and some refrigerant
remains in the system it may not be necessary to
change the compressor.
Electrolux Home Products Inc. does not approve the
use of the Sweep Charge for sealed system repair.
This method of servicing sealed systems is often used to
repair products in the field. The Sweep Charge does
not adequately remove moisture from the oil in the
compressor. In a R-410A system you will need to
replace the compressor if the product has had a low
side leak.
Testing for Refrigerant Leaks
If the system is diagnosed as short of refrigerant and
the system has not been recently opened, there is
probably a leak in the system. Adding refrigerant
without first locating and repairing the leak or replacing
the component will not permanently correct the difficulty.
The leak must be found!
Sufficient refrigerant may have escaped to make it
impossible to leak test effectively. In such cases, add a
Add sufficient refrigerant vapor to increase the pressure
to 75 lbs. per sq. in. Through this procedure, leaks are
more easily detected before discharging the system into
reprocess/recapture equipment. Check the low side for
leaks. Run the compressor 2 or 3 minutes and check
the high side for leaks. Recover refrigerant using an
EPA approved recovery system.
Checking For Internal Leaks
Before checking for internal leaks, check all accessible
system components and joints for leaks.
If an internal leak is suspected, it must be confirmed.
Use the following procedure:
1. Discharge the system by using refrigerant recovery
equipment. (See Evacuation & Recharging on page
6-16)
2. Pinch off and solder closed one end of the part of
the system to be tested.
of the part of the system to be tested.
4. Connect a pressure gauge and access valve to the
open end of the part of the system to be tested.
Pressurize to 250 lbs. using dry nitrogen or carbon
dioxide.
5. Leave the pressure on for 24 hours. Any drop in
pressure is an indication of a leak.
ÒÑÌÛ
The line piercing valve (clamp-on type) should be
used for test purposes only. It must be removed from
system after it has served its purpose.
