Decision essentials
Key points
Hum often means blocked rotor or air.
Silence may be supply or thermal protection.
Never energise dismantled equipment.
Filter troubleshooting
Split electrical from hydraulic
Confirm breaker, strip and timer without touching wet connections. Remove any damaged cable from service.
With power isolated, confirm full chamber, open valves and submerged intake.
Filter troubleshooting
Mechanical check unplugged
Remove grit and inspect rotor shaft. Allow specified thermal reset time.
If correct reassembly fails, replace or service rather than bypass protection.
From evidence to action
Decision matrix
| Situation | What to do | Why |
|---|---|---|
| Completely silent | Verify safe power supply | Separates electrical fault |
| Hums without flow | Unplug and inspect prime/rotor | Prevents overheating |
| Cable damaged | Remove from use | Electrical hazard |
Check the result
Record the symptom and time before intervening. Repeat the same check afterwards, watch breathing and behaviour, and keep a timeline; if the problem worsens, prioritise safety and reassess the diagnosis. For “Filter will not start: diagnose power, prime and impeller safely”, use never energise dismantled equipment as the final article-specific check.
Evidence
Sources and scope
Sources include institutions, technical studies and manufacturers. Chezur separates established mechanisms from editorial decisions for home aquariums.
- EHEIM — Operating and troubleshooting manual manufacturer
- University of Florida IFAS — Pumps and total head institution