Amana SR520T Service page 36

Component Testing
Component Description
Control, freezer Freezer temperature control is a capillary
temperature tube operating a single pole, single throw
(Non-electronic switch.
units)
Altitude Adjustment
When altitude adjustment is required on
a G.E. control, turn altitude adjustment
screw 1/7 turn clockwise for each 305
meters increase in altitude up to 3,050
meters.
In most cases the need for altitude
adjustments can be avoided by simply
turning temperature control knob to
colder setting.
Drier Drier is placed at post condenser loop
outlet and passes liquefied refrigerant to
capillary.
Evaporator Inner volume of evaporator allows
liquefied refrigerant discharged from
capillary to expand into refrigerant gas.
Expansion cools evaporate tube and fin
temperature to approximately -29 C
(-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 result of capillary on
suction line.
Refrigerant gas is pulled through suction
line by compressor to complete the
refrigerant cycle.
RS590000 Rev. 0
Test Procedures
Check for proper calibration with thermocouple capillary in air supply well by
recording cut-in and cut-out temperatures in middle setting. See tech sheet for
model being serviced for expected temperatures.
Check control contacts are opening by disconnecting electrical leads to control
turning control knob to coldest setting and checking for continuity across
terminals.
Altitude correction must be done on both "cut-in" and "cut-out" screws.
Altitude Counter in Meters
Meters Clockwise Turns
610 7/60
915 13/60
1220 19/60
1525 25/60
1830 31/60
2135 37/60
2440 43/60
2745 49/60
3050 55/60
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 the drier with Amana
part number B2150504.
Before opening refrigeration system, recover HFC134a refrigerant for safe
disposal.
Cut drier out of system using the following procedure. Do not unbraze drier.
Applying heat to remove drier will drive moisture into the system.
1. Score capillary tube close to drier and break.
2. Reform inlet tube to drier allowing enough space for large tube cutter.
3. Cut circumference of drier 3 cm below condenser inlet tube joint to drier.
4. Remove drier.
5. Apply heat trap paste on post condenser tubes to protect grommets from
high heat.
6. Unbraze remaining part of drier. Remove drier from system.
7. 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.
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.
!
To avoid severe personal injury or death 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.
For minute leaks
1. Separate evaporator from rest of refrigeration system and pressurize
condenser up to a maximum of 10 bars (140 PSI) with a refrigerant and dry
nitrogen combination.
2. Recheck for leaks.
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CAUTION
WARNING
45
April 1998