Fault Finding The Product - Grundfos Unilift AP35B Installation And Operating Instructions Manual

7. Fault finding the product

DANGER
Electric shock
Death or serious personal injury
- Switch off the power supply before
starting any work on the product.
- Make sure that the power supply cannot
be accidentally switched on.
Fault
1. The motor does not
start.
2. The motor protection
or thermal relay trips
after a short time of
operation.
3. The pump runs
constantly or gives too
little water.
Cause
a) No power supply.
b) The pump was stopped by the level
switch.
c) The fuses have blown.
d) The motor protection or thermal relay
has tripped.
e) The impeller is blocked by impurities.
f) Short circuit in the cable or motor.
a) The liquid temperature is too high.
b) The impeller is blocked or partly
blocked by impurities.
c) Phase failure.
d) Too low voltage.
e) The overload setting of the motor-
protective circuit breaker is too low.
f) Incorrect direction of rotation. See
section 3.4 Checking the direction of
rotation.
a) The pump is partly blocked by
impurities.
b) The outlet pipe or valve is partly
blocked by impurities.
c) The impeller is not properly fixed to the
shaft.
d) Incorrect direction of rotation. See
section 3.4 Checking the direction of
rotation.
e) Incorrect setting of the level switch.
f) The pump is too small for the
application.
g) The impeller is worn.
CAUTION
Sharp element
Minor or moderate personal injury
- Wear personal protective equipment.
CAUTION
Toxic material
Minor or moderate personal injury
- The product will be classified as
contaminated if it has been used for a
liquid which is injurious to health or
toxic.
- Wear personal protective equipment.
Remedy
Connect the power supply.
Adjust or replace the level switch.
Replace the fuses.
Wait until the motor protection
trips in again or reset the relay.
Clean the impeller.
Replace the defective part.
Use another pump type. Contact
your local Grundfos supplier or
sales support.
Clean the pump.
Call an electrician.
Call an electrician.
Adjust the setting.
Reverse the direction of rotation.
Clean the pump.
Clean the outlet pipe or valve.
Tighten the impeller.
Reverse the direction of rotation.
Adjust the level switch.
Replace the pump.
Replace the impeller.
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