Water pump is very loud or makes a rattling noise during operation.

Safety first: Unplug the unit and drain water before removing the pump.

Steps to quiet the pump:

• 1. Bleed air: Refill the reservoir and tilt the unit gently in different directions (with power off) to help air escape from the pump housing.
• 2. Clean pump inlet: Remove and clean any filter screen at the pump inlet. Check for debris inside the pump if accessible.
• 3. Check mounting: Ensure the pump is firmly attached to its bracket and that any rubber mounts are intact.
• 4. Replace pump: If noise persists and the pump feels rough when spun by hand, replace it with a HOMCOM-compatible circulation pump.

Note: A slight hum is normal, but loud rattling indicates a problem.