Gorman-Rupp Pumps S3A1 460V 3P All serial numbers Control Box - Manual (Page 20)

CONTROL BOXES OM−05169
TROUBLESHOOTING PAGE D − 1
TROUBLESHOOTING − SECTION D
Review all SAFETY information in Section A.
The electrical power used to operate
this control box is high enough to cause
injury or death. Obtain the services of a
qualified electrician to troubleshoot,
test and/or service the electrical compo-
nents.
Many of the probable remedies listed in the troubleshooting chart below require use of electrical test instru-
ments; for specific procedures, see Electrical Testing at the end of the troubleshooting chart.
When troubleshooting, also refer to the technical information accompanying the pump and optional equip-
ment.
TROUBLESHOOTING CHART
TROUBLE POSSIBLE CAUSE PROBABLE REMEDY
PUMP FAILS TO
START, OVERLOAD
UNIT NOT TRIPPED
(MANUAL MODE) Power source incompatible
with control box.
No voltage at line side of cir-
cuit breaker.
No voltage at line terminals
on bottom of overload unit in
control box.
Correct power source.
Check power source for blown fuse, open
overload unit, broken lead, or loose connec-
tion.
Check power source for blown fuse, open
disconnect, broken wire, or loose connection.
OVERLOAD UNIT
TRIPS Low or high voltage, or exces-
sive voltage drop between
pump and control box.
Power input phases not bal-
anced.
Control box not compatible
with pump.
Foreign object locking impel-
ler or bearing frozen.
Motor windings short-cir-
cuited.
Measure voltage at control box. Check that
wiring is correct type, size, and length. (See
Field Wiring Connections, Section B).
If imbalance exceeds 1 percent, notify power
company.
Electrical data on control box and pump
name plate must agree. Replace control box if
not in agreement.
Remove foreign material or replace damaged
bearing. If bearing is damaged, check for wa-
ter in motor housing.
Check motor windings with ohmmeter.