Component Testing
©2007 Viking Preferred Service
21
Component
Description Test
Procedures
Capacitor
Run capacitor connects to relay
terminal 3 and L side of line.
Some compressors do not require a run
capacitor; refer to the Technical Data
Sheet for the unit being serviced.
WARNING
To avoid electrical shock which can cause severe
personal injury or death, discharge capacitor
through a resistor before handling.
1. Disconnect power to refrigerator.
2. Remove capacitor cover and disconnect capacitor
wires.
3. Discharge capacitor by shorting across terminals
with a resistor for 1 minute.
4. Check resistance across capacitor terminals with
ohmmeter set on “X1K” scale.
•
Good – needle swings to 0 ohms and slowly moves
back to infinity.
•
Open – needle does not move. Replace capacitor.
•
Shorted – needle moves to zero and stays. Replace
capacitor.
•
High resistance leak – needle jumps toward 0 and
then moves back to constant high resistance (not
infinity).
Compressor When
compressor electrical circuit is
energized, the start winding current
causes relay to heat. After an amount
of starting time, the start winding circuit
turns off. The relay will switch off the
start winding circuit even though
compressor has not started (for
example, when attempting to restart
after momentary power interruption).
With “open” relay, compressor will not
start because there is little or no current
to start windings. Overload protection
will open due to high locked rotor run
winding current.
With “shorted” relay or capacitor,
compressor will start and overload
protector will quickly open due to high
current of combined run and start
windings.
With open or weak capacitor,
compressor will start and run as normal
but will consume more energy.
Resistance test
1. Disconnect power to unit.
2. Discharge capacitor by shorting across terminals
with a resistor for 1 minute.
NOTE:
Some compressors do not have a run capacitor.
3. Remove leads from compressor terminals.
4. Set ohmmeter to lowest scale.
5. Check for resistance between:
•
Terminals “S” and “C”, start winding
•
Terminals “R” and “C”, run winding
If either compressor winding reads open (infinite or
very high resistance) or dead short (0 ohms),
replace compressor.
Ground test
1. Disconnect power to refrigerator.
2. Discharge capacitor, if present, by shorting
terminals through a resistor.
3. Remove compressor leads and use an ohmmeter
set on highest scale.
4. Touch one lead to compressor body (clean point of
contact) and other probe to each compressor
terminal.
NOTE:
If reading is obtained, compressor is grounded
and must be replaced.
Summary of Contents for DDBF036LSS
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