Grundfos CR 10 User Manual

English (US)
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4. Fuses blow or circuit
breakers or overload
relays trip
a) Tank is too small. Check voltage at starter panel and motor. If
voltage varies more than - 10 %/+ 10 %, contact
power company. Check wire sizing.
b) Motor overload protection set too low. Cycle pump and measure amperage. Increase
size of overload protection or adjust trip setting
to maximum motor nameplate (full load) current.
c) Three-phased current is imbalanced. Check current draw on each lead to the motor.
Must be within - 5 %/+ 5 %. If not, check motor
and wiring. Rotating all leads may eliminate this
problem.
d) Motor short-circuited or grounded. Turn off power and disconnect wiring. Measure
the lead-to-lead resistance with an ohmmeter
(RX-1). Measure lead-to-ground values with an
ohmmeter (RX-100K) or a megaohmmeter.
Record values. If an open or grounded winding
is found, remove the motor, repair and/or
replace.
e) Wiring or connections are faulty. Check proper wiring and loose terminals.
Tighten loose terminals. Replace damaged
wires.
f) Pump is blocked or seized. Turn off power and manually rotate pump shaft.
If shaft does not rotate easily, check coupling
setting and adjust as necessary. If shaft rotation
is still tight, remove pump and inspect.
Disassemble and repair the pump.
g) Defective capacitor (single-phase motors). Turn off power and outlet capacitor. Check with
ohmmeter (RX-100K). When the meter is
connected to the capacitor, the needle should
jump towards 0 ohms and slowly drift back to
infinity ( ∞ ). Replace capacitor if defective.
h) Motor overload protection devices at higher
ambient temperature than motor.
Use a thermometer to check the ambient
temperature near overload protection devices
and motor. Record these values. If ambient
temperature at motor is lower than at overload
protection devices, especially where
temperature at overload protection devices is
above 104 °F (40 °C), replace standard
protection devices with ambient-compensated
protection devices.
Problem Possible cause Remedy

Grundfos CR 10 Specifications

General

Type	Centrifugal Pump
Liquid Temperature	-20°C to +120°C
System Pressure	Max 25 bar
Pump Housing	Stainless Steel
Impeller	Stainless Steel
Motor Type	Asynchronous motor
Frequency	50/60 Hz
Protection Class	IP55
Insulation Class	F
Max Head	Up to 160 m
Motor Power	0.37 kW
Approvals	CE, EAC