Strange extractor

[borstel]

Dear all,

I am new here to ask for advise, please.
My problem is the following:
In the apartment is a strange extractor fan and its motor is build in a wall between two rooms. It is not possible to see it and to get close to it.
However, it extracts air from the bathroom and from the kitchen.
It runs really all the time. I have lived here for almost a year and it never stopped running. Always same speed. This is why it was decided to switch it off in the evenings and back on in the mornings as it is so noisy in my room. I can hear the motor through the wall making a constant loud noise. Bsssssssssssss and so on.
The usual procedure after switching on is that the fan starts to accelerate, stops, makes a new acceleration and continuous running all the day.
Today is one of the days where it has decided to stop working. This means the switch is on, but it does not start to run, even if there is humidity or light in the bathroom. (Usually it does not care about these two things as it runs always which I am also not able to understand.)
When you switch the switch off and on, you can hear the fan starting to accelerate, but then it stops. In the past the fan exhibited this behaviour for 1-2 days and went back to normal business afterwards.

It is so strange. There is no manual and none of the other house mates does know anything about the fan. As I like to know the reason why it does not usually react on humidity neither on light in the bathroom and runs constantly, I would also like to know what triggers the strange behaviour of the fan.

Thank you very much for any advise.

Kind Regards,
B.

 

[Steve]

If it has a humidistat, then I would suspect this is the problem.

I dont understand the description you give of the fan. Do you mean its an in-line fan, with inputs from both kitchen and bathroom? Sounds a bit dodgy. Any chance of photos?

 

[borstel]

If it has a humidistat, then I would suspect this is the problem.

I dont understand the description you give of the fan. Do you mean its an in-line fan, with inputs from both kitchen and bathroom? Sounds a bit dodgy. Any chance of photos?

Hello Steve.
Thank you for your answer. I will try my best to explain it better.

I don't know what is an in-line fan. But the switch for the motor is in the utility room next to the boiler. Behind the wall of the utility room and between the walls of the living room and my room is some space. Inside this compartment is the motor for the fan. I know this because there is the source of the noise.
The switch in the utility room controls the fans in the kitchen and in the bathroom. Both look like this:
Picture. This is all I can see of it and the switch. Everything else is behind a wall and somebody has once cut out a square from the wall but I can't see into that hole.

When it is working, it runs always. No matter if the bathroom is wet after having a shower or not or if there was light switched on. It is running always on full power, never returns to a slow speed when nothing happens in the bathroom or in the kitchen. Kitchen is btw together with living room.
I always asked myself what triggers this strange fan.

I don't have currently a camera so I cannot do any photos.

Thank you for reading this long story.

Kind Regards,
B.

 

[Steve]

Perhaps the fan is wired to run constantly when the main switch to it is on. This, IMO would make sense, or else it would need two automatic triggers - one from the bathroom (a humidistat?) and one from the kitchen (timed?) and it would require some inventive wiring to achieve this. Being as this sounds like a rented place, it sounds like the landlord has gone down the cheap route and gone for a single inline fan with 2 inlets. (Inline fan is a fan with an input and exhaust, but no room terminus - the installer provides tube from the inlet to a room. The benefit is the room has less noise (usually).

This install sounds like it relies on the user to turn it on and off, if there are no other controls visible (motion sensors? timers? fan controls?).

 

[borstel]

Perhaps the fan is wired to run constantly when the main switch to it is on.

I hope not because it would mean I have to with a constant noise background and it is really noisy. I don't make it up

This, IMO would make sense, or else it would need two automatic triggers - one from the bathroom (a humidistat?) and one from the kitchen (timed?) and it would require some inventive wiring to achieve this. Being as this sounds like a rented place,

I have rented a room and when I visited it I could not hear the fan. Perhaps it was switched off on purpose. The landlord bought this apartment from a company. I think, he does not know about this technique.

it sounds like the landlord has gone down the cheap route and gone for a single inline fan with 2 inlets. (Inline fan is a fan with an input and exhaust, but no room terminus - the installer provides tube from the inlet to a room. The benefit is the room has less noise (usually).

This install sounds like it relies on the user to turn it on and off, if there are no other controls visible (motion sensors? timers? fan controls?).

What is a room terminus , please? No, I could never see a motion sensor, a timer or a fan control. There is only the switch in the utility room.
But one more question, please. When you switch the fan on through the switch in the utility room, why does the fan start to accelerate, trying to reach speed and running perhaps 5secs on full speed, and stops again? Usually, when the fan is working, it shows this behaviour, stops, and returns to full speed and runs on full speed until the evening.

At the moment the switch is turned on, but all the afternoon it did not start to run constantly. Even if the landlord tried to switch it off and on 5times and 10time, it showed only this acceleration movement and went back in a quite state. Now he is terrified of mould could start to spread around.

 

[Steve]

This is an inline fan kit. The big white bit is the inline fan.

Bottom left is a room terminus (like the one you linked to).

Far right is the outside terminus.

The metal tube is the expandable metal ducting that goes between them all.


Many fans are wired so that YOU have to turn them on and off - its not unusual, and as I said its a cheap option.

 

[borstel]

Many fans are wired so that YOU have to turn them on and off - its not unusual, and as I said its a cheap option.

Okay, but I still assume they should start and work reliable once they were switched on Not showing once this behaviour and another day another one.
Dear Steve, thank you for explaining this to me. I guess the best thing what I could do is looking for another room.

 

[Steve]

If its on, it shoudl be on. If its off it should be off. No form of automation would give the operation you describe.

Ask the landlord to provide some sort of automation and a new fan.

If the room is all inclusive bills, tell him its wasting his electricity as you are leaving it on all day

If its not all inclusive, tell him you forget to turn it on and theres damp forming

Either way he'll want to fix it

 

[borstel]

If its on, it shoudl be on. If its off it should be off. No form of automation would give the operation you describe.

Thank you for your confirmation that something is wrong here.
Thank you, Steve. Unfortunately, your other suggestions won't work as the landlord is like the fan itself