Maytag PCF2700ACW Service Manual page 7

Component Testing
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 resistor before attempting to service.
Ensure all ground wires are connected before certifying unit as repaired and/or operational.
Component Description
Drier Drier is placed at post condenser loop
outlet and passes liquefied refrigerant to
capillary.
Desiccant (20) 8 x 12 4AXH - 7 M>S> -
Grams
Defrost timer Timer motor operates only when freezer
control is closed.
After specified amount of actual
operating time, inner cam in timer throws
the contacts from terminal 4, compressor
circuit, to terminal 2, defrost
thermostat/defrost heater circuit.
After specified defrost cycle time, timer
cam resets the circuitry through terminal
4 to compressor.
Component Description
Evaporator Inner volume of evaporator allows liquid
refrigerant discharged from capillary to
expand into refrigerant gas.
Expansion cools evaporator tube and fin
temperature to approximately -20°F
transferring heat from freezer section to
refrigerant.
Passing through suction line to
compressor, the refrigerant picks up
superheat (a relationship between
pressure and temperature that assures
complete vaporization of liquid
refrigerant) as the result of capillary tube
soldered to suction line.
Refrigerant gas is pulled through suction
line by compressor, completing
refrigeration cycle.
©2004 Maytag Services
!
WARNING
Test Procedures
Drier must be changed every time the system is opened for testing or
compressor replacement.
NOTE: Drier used in R12 sealed system is not interchangeable with
drier used in R134a sealed system. Always replace drier in R134a
system with Amana part number B2150504.
Before opening refrigeration system, recover HFC134a refrigerant for safe
disposal.
1. Cut drier out of system using the following procedure. Do not unbraze drier.
2. Applying heat to remove drier will drive moisture into the system.
3. Score capillary tube close to drier and break.
4. Reform inlet tube to drier allowing enough space for large tube cutter.
5. Cut circumference of drier 1 ¼" below condenser inlet tube joint to drier.
6. Remove drier.
7. Apply heat trap paste on post condenser tubes to protect grommets from high
heat.
8. Unbraze remaining part of drier. Remove drier from system.
9. Discard drier in safe place. Do not leave drier with customer. If refrigerator is
under warranty, old drier must accompany warranty claim.
To avoid death or severe personal injury, cut drier at correct location.
Cutting drier at incorrect location will allow desiccant beads to scatter. If
spilled, completely clean area of beads.
1. To check timer motor winding, check for continuity between terminals 1 and 3
of timer.
2. Depending on rotating position of the cam, terminal 1 of timer is common to
both terminal 2, the defrost mode, and terminal 4, the compressor mode.
There should never be continuity between terminals 2 and 4.
3. With continuity between terminals 1 and 4, rotate timer knob clockwise until
audible click is heard. When the click is heard, reading between terminals 1
and 4 should be infinite and there should be continuity between terminals 1
and 2.
4. Continuing to rotate time knob until a second click is heard should restore
circuit between terminals 1 and 4.
Test Procedures
Test for leaks in evaporator with electronic leak detector or with soap solution.
Compressor oil is circulated with refrigerant; check for oil when checking for
leaks.
For minute leaks
1. Separate evaporator from rest of refrigeration system and pressurize
evaporator up to a maximum of 140 PSI with a refrigerant and dry nitrogen
combination.
2. Recheck for leaks.
To avoid severe personal injury or death from sudden eruption of high
pressures gases, observe the following:
Protect against a sudden eruption if high pressures are required for leak
checking.
Do not use high pressure compressed gases in refrigeration systems
without a reliable pressure regulator and pressure relief valve in the
lines.
16023030 Rev. 0
!
WARNING
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WARNING
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