Compare the sound with normal operation
A heat pump makes sound when operating. The fan, compressor and circulation through the system may be perceived differently depending on the time and location. A significant change, repeated knocking, scraping or a vibration that was not noticeable before deserves attention.
A fault cannot be identified solely from a description such as it makes a lot of noise. Start by specifying whether the sound is new, whether it has increased and whether it coincides with reduced comfort or a warning on the controller.
Identify where you hear it
Explain whether you hear it near the outdoor unit, inside the home or through a wall. A sound heard in a bedroom does not prove that it originates there. The equipment's location and the transmission of vibration form part of the technical assessment.
You can walk around accessible areas of the home and take notes without touching the installation. If the unit is on a roof or in a difficult-to-access location, do not approach it to make a recording. Describing the sound from the place where it causes disturbance is still useful information.
Relate the sound to what the system is doing
Note whether it appears at start-up, during prolonged operation, when heating hot water or during a pause. Also state whether it occurs only at night or is masked by other sounds during the day. This helps distinguish an actual change in the equipment from a change in listening conditions.
If it is safe, make a short recording from the same position at different times. Include the time and the mode shown on the controller. Do not rest your phone on the casing or put objects through a grille to obtain a closer recording.
Do not use an app as an acoustic diagnosis
A phone reading may provide a personal reference for a situation, but it is not equivalent to a professional measurement and cannot determine compliance with an acoustic limit. It is also easy to compare different quantities: the unit's sound power and sound pressure at a particular point do not describe the same thing.
When reporting a disturbance, identifying the place, time and character of the sound is more useful. If neighbours are affected, gather those observations calmly. The solution may require assessment of operation, the installation and its surroundings.
Avoid measures that could make the problem worse
Do not tighten supports, move the unit or insert wedges to remove a vibration. Nor should you put it in an improvised box or screen: any acoustic solution must respect the model's ventilation, access and safety requirements.
Some equipment offers a quiet mode, but its behaviour and limits depend on the system. Ask how it is used and what effect it can have on available capacity. Switching it on is not a substitute for inspection when there is a new sound, mechanical scraping or abnormal vibration.
Request an assessment with a specific description
A useful message might explain that, since a particular date, a humming sound can be heard in a particular room during hot water heating, with no known recent changes. Add the model and a recording if available. There is no need to suggest a component for replacement.
If there is violent knocking, smoke, a burning smell or signs of damage, avoid continuing to use the equipment and seek assistance in line with its safety instructions. For other cases, Red Málaga can assess the information and confirm the appropriate inspection for your installation.
More common questions
Does hearing it more at night prove there is a fault?
Not necessarily. The surroundings may be quieter and the equipment may be operating under different conditions. Describe the change and establish whether there are new sounds, persistent disturbance or other associated symptoms.
Sources and technical reading
Some source documents are available in Spanish.