Thermo King MD-MT, Operator'S Manual

Page: 144 / 192

Electric Standby Diagnosis
144
Contact chatter Low battery voltage Check voltage condition. Check
momentary voltage dip during
starting—low voltage prevents
magnet sealing
Defective or incorrect coil Replace coil
Poor contact in control circuit Check auxiliary switch contacts and
overload relay contacts. Check for
loose connections in control circuits
Contact welding or freezing Abnormal in-rush of current Check or grounds, shorts or
excessive motor load current
Low voltage Correct voltage condition. Check
momentary voltage dip during
starting
Foreign matter prevents contacts
from closing Clean contacts
Rapid cycling Check for cause of short cycling
(such as thermostat)
Short circuit Correct fault
Battery is not recharging Loose connections in electrical
system Check all electrical connections and
charging system
Worn brushes in alternator Replace brushes
Voltage regulator faulty Repair or replace regulator
Battery defective Replace battery
Alternator defective Repair or replace alternator
Loose belt Tighten belt
Dirty battery terminals Clean and retighten
Alternator relay defective Replace relay
Fuse F309 open Replace fuse
Condition Possible Cause Remedy