The system needs to be bled, there is still some air in the piping causing the noise you are hearing.
It has to do with the metal and other materials the heater is made of and the effects of heat on them. As the metal heats up, it expands and this makes noise. Sometimes the electricity will cause the resistive heating elements to vibrate somewhat, and this will also make a buzzing sound.
Most are up underneath the dashboard. Turn on the heater blower motor and listen where the sound is coming from. The heater core is behind that sound.
there is a bit of rubish caught in the heater fan.
If it's inside your apartment and not out side (which laws would vary in that case) then yes. You can record sound and have video. Hidden or proclaimed.
A complaint to the police will do it. Or a complaint to the building managers if you are in an apartment.
The heater makes a humming sound.
no, u should not hear anything when block heater is plugged in
either need a blend door accuator or a heater box
It might. Does the sound follow the space heater to a different outlet? If you place your head between the space heater and the outlet, does the hissing sound come from the wall, or from the heater? Sometimes different sounds come from different sides of applicances, and these sounds can reflect off the wall. A standard vacuum cleaner and some electric irons draw about the same current as a space heater. Is the sound present with either of those plugged into the same outlet instead? It might be a snake, saying "thank you" for the warmth.
An apartment is usually referred to as a 'flat' in all of the UK - which includes England, However, people sometimes use the word 'apartment' - particularly if they want to make it sound a little bit 'up-market'.
Most likely your fan blade mechanism inside heater motor is discounted from motor, or loose from motor.
Usually when a car makes squealing sound after accelerating with the heater on, the serpentine belt is a little loose. It likely needs adjusting by a professional.