Bathroom extractor Fan.... Should it run continuously when light is On ?

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Some fans have two modes:
  • a trickle mode where the fan runs continuously at a slower speed
  • Boost - when the light comes on with a timer over-run
 
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I have a humidistat fan and the wife insists on using the shower just before bedtime. Bloody thing ran for 2 hours last night because of the rain and humidity. Changed it to timer mode this morning. The mode was changed previously because of it continually running.

I suspect the housing association are bringing their stock to todays standards.
 
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You can get fans with built-in humidistats or overrun timers or thermostats or wired to any sort of external device- but they're more expensive than basic fans, humidistats don't work that well in this country, timer is something else to go wrong & v annoying when you go to the loo at 3am and the fan whirrs on for another half an hour. If the tenant is paying leccie bill keep it simple- do check it is ducted as above and do clean it (and duct) regularly to combat fluff/gunge build-up
I don’t like fans that come on every time with the light and then run on a timer for a couple of reasons - the fan coming on if someone uses the bathroom at 3.00 on the morning or when someone pops in for just a wee when the heating is on and all your warm air is blown out. I have a fan with a humidistat and a timer. Under normal conditions, fan does not come on every time light is switched on and the humidistat works fine as the fan comes on not long after the shower is used and continues until the humidity reduces to a pre-set level. For manual override, I have a pull cord switch in the corner where the WC is and you can reach that when seated. ;) Turn it on and then off again to get the timer to kick in before leaving the bathroom whether the light is on or off. Works for me.
 
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It really bugs me to have a fan that comes on when you turn the bathroom light on for much the same reason Mottie outlines. I'll add another one too - when relaxing in a bath with the lights dimmed having the fan run all the time really grates. So, when i had the bathroom done i had the switch line for the fan run to the external light swtich, where i have a dimmer for the lights and a 'push to make' button to turn the fan on. Works really well - no fan at 3am,or in the bath and it's not hardship to turn the fan on when switching the lights off - my hands there anyway
 
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Assuming the timer on the fan has been set to something sensible like 15 minutes, the fan should only run for a short time after the light has been switched off.

You have indicated that you think the light is left on all night.

The question has to be, why is this person leaving the bathroom light on all night??

Most fan set-ups like this have what is known as a 3 pole fan isolator - which should isolate just the fan completely. This should be situated in a convenient place.

If there is one, perhaps your neighbour could kindly switch it off before each long session every night of leaving the bathroom light on.
 
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if the fan was so quiet you can barely hear it

and so economical it barely registers a cost

would you still be opposed to ventilation?
 
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Assuming the timer on the fan has been set to something sensible like 15 minutes, the fan should only run for a short time after the light has been switched off.

You have indicated that you think the light is left on all night.

The question has to be, why is this person leaving the bathroom light on all night??

Most fan set-ups like this have what is known as a 3 pole fan isolator - which should isolate just the fan completely. This should be situated in a convenient place.

If there is one, perhaps your neighbour could kindly switch it off before each long session every night of leaving the bathroom light on.

No idea, why the neighbour insist on leaving bathroom light on and it’s unlikely they’re using the bathroom for such a length of time, especially at 3am

I only actually notice if I awake during the early hours and once noticed, I can hear a continuous hum.

My thinking, should the fan eventually and automatically turn off after a timed period even though the light remains switched on ?

My concern was risk of the fan overheating and maybe causing a fire.

Also, from past experience of my neighbours, any request to kindly switch the fan off before a long session or to stop leaving the bathroom light on, will just be ignored.
 
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My thinking, should the fan eventually and automatically turn off after a timed period even though the light remains switched on ?
No. Light on = fan on. Timed period starts when the light is switched off.

My concern was risk of the fan overheating and maybe causing a fire.
Not going to happen.

The fact that you can easily hear sounds from another flat is the real problem here. Fan is unrelated.
 
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The fact that you can easily hear sounds from another flat is the real problem here. Fan is unrelated.

Not a lot I can do about the noise.

If there was a risk of fire, especially due to the Grenfell tower block fire, then the HA would probably do something.
 
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You can get fans with built-in humidistats or overrun timers or thermostats or wired to any sort of external device- but they're more expensive than basic fans, humidistats don't work that well in this country, timer is something else to go wrong & v annoying when you go to the loo at 3am and the fan whirrs on for another half an hour. If the tenant is paying leccie bill keep it simple- do check it is ducted as above and do clean it (and duct) regularly to combat fluff/gunge build-up

My humidistat fan in my upstairs bathroom is great. When I get up in the morning and run the bath it kicks in as required and stops when it should. From memory it was about £70. Admittedly, the humidistat added about £30 to the cost but, IMO, it was worth it.

At the time, I didn't want a fan that would kick in at 3AM when you turn the lights on to go for a pee and I was aware that I would not turn the lights on when using the bath or shower when the sun is up.

The fan in my downstairs bathroom is a larger capacity Icon with a motion sensor and humidistat. From memory, that was about £130. I think the PIR sensor sees dead people. It will start running at random times of the day.

That said, I did fit a humidistat fan for a customer that would kick in if it was raining outside. It was a PITA, the adjustment was wayyy to sensitive.
 
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