TM9-4120-400-14
4-37.
COMPRESSOR START CAPACITOR C5, single phase units only. - continued
NOTE
Compressor start capacitor is installed on all units. The capacitor is connected to the start
relay only on units using Welco compressors.
Ground all capacitors before touching.
INSPECTION
Check capacitor for general condition and loose, broken, or damaged terminals.
NOTE
The ohmmeter test does not show the behavior of a capacitor under load. Such testing
requires special equipment which is not economically practical for testing small capacitors.
If breakdown under load is suspected, replace the capacitor.
TESTING
1. Tag and disconnect leads.
Using a multimeter set to read high resistance, place meter leads on terminals of capacitor.
2.
If capacitor is good, multimeter needle should move rapidly toward low end of scale then slowly return toward
3.
infinity, stopping at value of attached bleed resistor. The capacitor is internally short circuited if needle moves
to zero and stays there. The capacitor has an open circuit if the needle only indicates value of attached bleed
resistor. Replace if capacitor indicates short circuit, open circuit, or has other damage.
4.
See the wiring diagram figure 4-4 and tags and connect the wire leads. Remove tags.
REPLACEMENT
1.
Using a screwdriver with an insulated handle, discharge capacitor.
Loosen four screws (1) securing two straps (2) holding compressor start capacitor (C5) (3) to top rear panel.
2.
Do not remove straps.
Remove capacitor (3) by sliding out from under straps.
3.
4. Tag and disconnect leads.
Place capacitors (3) into straps (2).
5.
See the wiring diagram figure 4-4 and tags and connect the wire leads. Remove tags.
6.
Tighten four screws (1) securing straps (2) holding capacitor (3).
7.
NOTE
FOLLOW-ON MAINTENANCE:
Install top rear panel (para 4-11).
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