Evacuation And Charging; Evacuation - Maytag MFI2266AES Service Manual

Service Procedures
To avoid risk of electrical shock, personal injury, or death, disconnect electrical power source to unit, unless test
procedures require power to be connected. Discharge capacitor through a 10,000 ohm resistor before attempting
to service. Ensure all ground wires are connected before certifying unit as repaired and/or operational.

Evacuation and Charging

!
CAUTION
To avoid risk of fire, sealed refrigeration system
must be air free. To avoid risk of air contamination,
follow evacuation procedures exactly.
NOTE: Before opening any refrigeration system, EPA
regulations require refrigerant in system to be
captured for safe disposal.
Proper evacuation of sealed refrigeration system is an
important service procedure. Usable life and
operational efficiency greatly depends upon how
completely air, moisture and other non-condensables
are evacuated from sealed system.
Air in sealed system causes high condensing
temperature and pressure, resulting in increased
power requirements and reduced performance.
Moisture in sealed system chemically reacts with
refrigerant and oil to form corrosive hydrofluoric and
hydrochloric acids. These acids attack motor windings
and parts, causing premature breakdown.
Before opening system, evaporator coil must be at
ambient temperature to minimize moisture infiltration
into system.

Evacuation

To evacuate sealed refrigeration system:
1. Connect vacuum pump, vacuum tight manifold set
with high vacuum hoses, thermocouple vacuum
gauge and charging cylinder as shown in illustration.
Evacuation should be done through I.D. opening of
tubes not through line piercing valve.
2. Connect low side line to compressor process tube.
3. Connect high side line to drier/process tube.
4. Evacuate both simultaneously. With valve "C" and "F"
closed, open all other valves and start vacuum pump.
14
!
WARNING
Thermistor
Vacuum Gauge
Compressor
Equipment Setup For Evacuation And Charging
5. After compound gauge (low side) drops to
approximately 29 inches gauge, open valve "C" to
vacuum thermocouple gauge and take micron
reading.
NOTE: A high vacuum pump can only produce a good
vacuum if oil in pump is not contaminated.
6. Continue evacuating system until vacuum gauge
registers 600 microns.
7. At 600 microns, close valve "A" to vacuum pump and
allow micron reading in system to balance. Micron
level will rise.
• If in 2 minutes, micron level stabilizes at 1000
microns or below, system is ready to be charged.
• If micron level rises above 1000 microns and
stabilizes, open valve "A" and continue evacuating.
• If micron reading rises rapidly and does not
stabilize, a leak still exists in system.
Close valve "A" to vacuum pump and valve "C" to
vacuum gauge. Invert charging cylinder and open
charging cylinder valve "F" to add partial charge for
leak checking. With leak detector, check manifold
connections and system for leaks. After locating
leak, capture refrigerant, repair leak, and begin at
step 1.
16026312
High Side Gauge
Low Side Gauge
D
E
Valve
Valve
C
Charging Hose
B
Compressor
Process
A
Tube
.6 cm Copper
Tubing
Vacuum Pump
Drier/Process Tube
Charging Hose
F
Valve
Charging
Cylinder
©2006 Maytag Services