What changed at the unit?
Heat pump making unusual noise: safe next steps
A new rattle, buzz, knock or squeal is worth recording. Do it from the usual standing distance. Do not press a vibrating panel or cycle the system to make the noise return; sound alone cannot identify what is happening inside.
Observed symptom ≠ diagnosed fault
What this can tell you
A sound recording is evidence, not a diagnosis
A fan rush during heating, a single changeover click and a repeated metallic knock are not the same observation. Sound alone still cannot name a fault. A new, repeated or escalating noise is worth documenting, especially when the controller changes at the same time.
Do not move closer to locate a sound inside the cabinet, hold a panel, or run the system repeatedly to reproduce it. If it is safe to remain nearby, a short recording from the usual standing distance can help official support or a licensed technician.
Four checks, then a route
Choose a clear next step
Does the noise accompany smoke, burning smell, sparks or another red flag?
Stop using the unit and take the urgent safety route without trying to reproduce the sound.
Does a code or message appear when the sound occurs?
Copy the display and search it exactly; do not cycle the system to make the code return.
Is the brand and complete model number already known?
Use the brand route to compare the correct model context and contact official support.
Is the unfamiliar noise recurring without a source-backed route?
Arrange licensed repair help and share when the sound occurs plus any safe recording.
Letters or numbers on the controller?
Copy the display before choosing support
Search any code that appears with the noise. A verified result reports what that controller documents; it does not prove the code and sound share the same physical cause.