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6
TEMPERATURE FAILURES:
Fairbanks Nijhuis control panels supply the correct circuitry for moisture and heat sensor connections.
Your mixer is equipped with temperature fail sensor thermostats attached directly to the motor windings. The
thermostats open if the motor windings see excessive heat and, in turn, open the motor contactor in the control panel,
breaking the power to the mixer.
When the motor is stopped due to an overheated condition, it will not start until the motor has cooled and the heat
sensor reset button is manually pushed on the front of the control panel.
Failure to use proper circuitry and to connect the motor overheat protection in the control panel would negate
all warranties and Factory Mutual Approval.
Before handling the mixer and controls, always dis con nect the pow er first. Do not smoke or use sparkable
electrical devices or flames in a septic (gas eous) or possible septic sump.
TROUBLESHOOTING:
1. Mixer does not run in Hand position.
a. Check mixer circuit breaker and control fuse for trip ping or blown condition.
b. Check incoming power volt age and control cir cuit volt age.
c. Check VFD to see if it is tripped. Reset VFD if tripped and check mixer current with ammeter.
d. With the power off, check motor heat sensor continuity.
e. Check wiring of mixer to con trol panel. It should agree with the sche mat ic.
2. Mixer does not run in Auto position.
a. Check items (a.) through (e.) per Item #1 above.
b. Check knob settings on timer to ensure proper sequencing. Check both On and Off Time range selector
knobs as well as On and Off Time adjustment knobs.
c. If mixer does not run in Auto mode, check Auto circuit wiring in panel.
3. Mixer runs, but run light does not energize.
a. Re move light and check with an ohmmeter.
b. Check run light wir ing.
4. Severe humming/chat ter ing of control relay.
a. There may be low voltage. Check voltage at primary and secondary of control transformer us ing a volt me ter.
This low voltage condition may cause severe chat ter ing and burnout of relay.
b. Relay may have dust around magnet of coil struc ture. Dry or clean as re quired.
c. Check voltage to the control panel. Relays require a minimum of 80% of full volt age to pull in without chatter.
If the problem is a re cur ring one, measure voltage with recorder on a 24 hour basis.
d. Dry out the junction box (if furnished); moisture in the junction box may cause relays to energize intermittently.
5. Short cycling mixer.
a. Check timer controls.
6. Run light stays on.
a. Selector switch may be in the Hand position.
7. Nuisance tripping of overload on VFD or cir cuit break ers.
a. Check mixer amp draw with amp probe and compare to nameplate amps on mixer.
b. The propeller may be locked up due to excessive debris or solids.
c. Possible motor failure (fault in windings).
d. Mixer may be miswired to ter mi nal block.
e. Voltage and current unbalance. Voltage un balance on three phase power sources can cause motor current
to become un bal anced and exces sive heating will re sult. Trip ping of the over load protection and premature
motor failures can be expected if the current unbalance exceeds five percent.
NOTE:
NOTE:
WARNING:
FBM(X)20 Basin Mixer Control Panel
Instruction and Service Manual
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