Agree with flameport, if it only runs when humidity levels rise then it's already too late to prevent condensation, it needs to run before humidity levels rise. I.E as soon as the room is occupied.
Another humidistat extractor fan question
- Thread starter ercole89
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- extractor fan humidistat
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Fans do not prevent condensation.
I have always thought that humidistats run on after the level has been reached - but only because I presumed they started the fan in the same way as the switched live. Obviously this one doesn't.
There would be no way of telling, when it is plugged in, as one can't know the humidity level of either the room or the humidistat knob.
Either way it doesn't matter.
I have always thought that humidistats run on after the level has been reached - but only because I presumed they started the fan in the same way as the switched live. Obviously this one doesn't.
There would be no way of telling, when it is plugged in, as one can't know the humidity level of either the room or the humidistat knob.
Either way it doesn't matter.
Not even when a bathroom is full of water vapour after a steamy shower and wet surfaces? And it sucks the wet air outside the house? And dry air flows in to replace it?
I said prevent.
Nope. Too late to prevent by then.
Wet surfaces, eh? How did that happen?
Nope. Too late to prevent by then.
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my bathroom has an extractor wired with the light switch. So it starts running before you turn on the tap; runs throughout your ablutions, and continues running afterwards.
It does not get condensation.
In cold weather the window mists up, but clears by the time you've brushed your teeth and put on your jammies.
It used to get condensation prior to the extractor.
It does not get condensation.
In cold weather the window mists up, but clears by the time you've brushed your teeth and put on your jammies.
It used to get condensation prior to the extractor.
Hmm. Could this by why the third core is needed then? Maybe tech support were right.
No.
When switched off, the only thing connected to terminal T would be a wire which doesn't do anything.
Having looked at the instructions, they do state the humidistat does work in the expected way, i.e. runs on, although you would never be able to tell, of course, (unless it clicks when humidistat switches off).
Yours stops if you unplug the humidistat. I don't know if that is just what it does.
It does seem to have some sophisticated way of measuring RH before it would turn on.
Can you not connect a temporary switch between L and T to at least show that it works properly?
Yours stops if you unplug the humidistat. I don't know if that is just what it does.
It does seem to have some sophisticated way of measuring RH before it would turn on.
Can you not connect a temporary switch between L and T to at least show that it works properly?
For the last week the RH of the outside air (at Heathrow) has not dropped below 75%.
What have you got your fan set to?
What have you got your fan set to?
Sometimes it stops when the humidistat is unplugged, sometimes it carries on (all night the other night when we left it to see). Neither of those is what's supposed to happen. It should carry on for x minutes, where x here = 0.5 with what we have the timer potentiometer currently set to. It supposedly can be set to 30s to 30 mins run-on after the humidistat turns off. But as you say as there's no obvious sound or anything when the humistat turns off.
It's supposed to only trigger if humidity spikes. I could connect a temp switch if I bought the bits I guess. I'll look into it.
95% supposedly if the instructions are the right way round (have tried the other way round too!). Very damp most of the time here in SE Wales. So shouldn't really be triggering at all at the moment.
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Another idea - could be completely wrong - is there something about adjusting potentiometers only supposed to be done when the fan is isolated (turned off at the fuse box?). We've been adjusting the timer and humidistat without the fan being isolated. Again can't see why it would make a difference but the first person I spoke to at tech support said it should be done that way. We ignored her because we thought she was talking rubbish..
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Ok.
No.
It might not take effect until the next time it is turned on. I don't really know.
Apart from above, what possible difference could it make?
Thinking out loud. By reference to the wiring diagram (image), and to the thread here: https://www.diynot.com/diy/threads/...p-the-wiring-to-my-bathroom-extractor.240947/
Would it be a stupid idea to connect up the T to the L with a spare bit of wire? Is that dangerous in any way? The thinking out loud bit is about perhaps the fan needs something going into the 'T' to work properly. 'T' for timer? Or, can I somehow disconnect the timer? Or does anything here help? http://forums.moneysavingexpert.com/showthread.php?t=2277431
Would it be a stupid idea to connect up the T to the L with a spare bit of wire? Is that dangerous in any way? The thinking out loud bit is about perhaps the fan needs something going into the 'T' to work properly. 'T' for timer? Or, can I somehow disconnect the timer? Or does anything here help? http://forums.moneysavingexpert.com/showthread.php?t=2277431
That would (or should) set the fan going but it will not stop - until the link is removed (from either terminal) and timer runs down.
I did not want to suggest that as it would be working with live wires, which is not advisable/allowed.
Don't you have a spare switch anywhere?
I did not want to suggest that as it would be working with live wires, which is not advisable/allowed.
Don't you have a spare switch anywhere?
No but can get hold of one. I have a basic understanding of electronics but no more than that, I'd prefer to stay away from the practical implementation stuff and get the experts in usually, it just seems silly to do that as we're all in agreement that it should be working how it's currently wired up. Sigh.. I'll ring tech support again tomorrow and explain that as it's not wired into the light switch it doesn't need to be 3-core, and see if they can actually help! At least now I have more information 
Thanks again.
Thanks again.DIYnot Local
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