humidistat fan

[stuartR1963]

Hi guys, first of all merry christmas to all, I fitted a humidistat extractor fan im my bathroom about 4 years ago, the reason I chose a humidistat fan is because i hoped the fan would come on on its own accord whenever the humidity got to high, eg showering, instead on the traditional just coming on with the light. I thought it would be irritating with the fan running with the light when you are trying to relax in a comfy bath. I could of had a seperate switch for the fan but I new for a fact it would never be switched on (teenagers).

The trouble is the fan does not operate when the shower is in use which is ****ing irritating and getting on my nerves. I tried messing around with the potientiometer adjustor in the fan but its no use, its either too sensitive or it does not come on at all, i cannot find the balance.
Its worth noting that the cover is quite discoloured and the fan pcb is blackened in one area near some capacitors, it is not roasting or anything but its warm,
Is it normal for a fan pcb to be rather burnt?

My question is how do I get it working? Does it need replaced? if so its a greenwood 6 inch fan about 215mm by 215mm. Or do I just need to fanny around with the adjustor?
The bathroom is not particularly big its about 2m by 2m.
cheers

I hope this makes sense I am rather ****ed at the momernt, I just drank a few buds and a whole bottle of red wine (14%), so I am rather light headed just now.
any help will be great, I will be back when i am somewhat sober but I can observe the answer just now even though im a bit ****ed
cheers

 

[Taylortwocities]

The problem with humidity fans is that we are living in a soggy damp country and the background humidity is high. Your average humidity fan has trouble detecting between you having a shower and the regular dampness.
Best solution is to ditch the humidity detection and fit something like a flow switch on the shower that is triggers a timer fan.

Sorry, CBA to respond to the rest. I’m having problems with something called Merlot.
Ding dong.

 

[ericmark]

I also gave up with the humidistat idea, to me the problems are:-
1) As it hits around 90% it gets to a point where it holds moisture, tried using humidity meters in the woodland, and found they got too wet, and needed taking in doors to dry out which really defeated the whole idea.
2) The damp air needs circulating to reach the humidistat, by time it triggers the unit it is very damp, so return to 1) above, unless something like a fan heater in the room it takes too long.
3) % humidity is linked to temperature, so unless drawing in air as warm as air being blown out, then as soon as it starts the temperature drops so it has to wait until either the air has become much drier or some thing warms up the air.

If the fan was low speed and the humidistat turned it to high speed it may work, or if placed where natural draft brings the room air to it, however I put it right above the shower, and it had auto shutters, so as soon as it opened and ran it got very damp air, so would take an hour or so to dry out again.

 

[stuartR1963]

The fan also has a timer, I think I will just hook up the switch live and have it come on with light as the other fan does in the en suite, The fan just has permanent live (red) and neutral connected (blue) at the moment, switch live is availiable (yellow) its just not connected to fan but its there with enough slack. If I have a bath I can always just switch the fan off at the isolater but I guess you would get used to it after a while and filter the noise out.
just one more question, is it normal for fan pcbs to be blackened overtime? like I say there is a burn mark near a capacitor and big resistor, the fan still works so I guess nothing has fried, It may be normal operation or it may not?, let me know cheers.

 

[ban-all-sheds]

Best solution is to ditch the humidity detection and fit something like a flow switch on the shower that is triggers a timer fan.

If it's a mixer shower, a temperature sensor on the hot feed would be easier to retrofit.

If it's electric then the fan can be triggered by turning the shower isolator on

 

[flameport]

is it normal for fan pcbs to be blackened overtime?

Yes, the resistor gets fairly hot in normal operation, so some discolouration of the PCB is inevitable.

 

[stuartR1963]

Yes, the resistor gets fairly hot in normal operation, so some discolouration of the PCB is inevitable.

Thanks thats good to know cheers

Best solution is to ditch the humidity detection and fit something like a flow switch on the shower that is triggers a timer fan.

I actually quite like that idea and it may be an option I might consider if its not too complex.

If it's electric then the fan can be triggered by turning the shower isolator on[/QUOTE]
Its a power shower which is fed from the roof tank and hot water cylinder, there is an electrical supply to it via a 3 amp fused spur as its just a pump. The pipe work that supplies the shower is accessible under the bath panel, could it be possible to fit a flow switch there to trigger the fan? getting the cable to the fan wont be much an issue, or does it need to be done in the shower itself? do you need to cut in too any pipes? or can it clip on?

Is there another way maybe, like fitting a contactor, somehow with a multimeter find the switch live that activates the pump in the shower when there is flow, and use that too trigger the contactor and activate the fan? cheers

Or is it just better to avoid the above and have the fan come with the light the traditional way?
thanks

 

[stuartR1963]

The shower is an old mira event if that helps, the pump is built into the shower

 

[amfisted]

Stuart, I have a humidistat fan in my bathroom and it works quite well. It nearly always comes on during a shower, and sometimes it fires up when you fill the sink with hot water. The bathroom has been more or less clear of mould since I fitted it. I have a separate pullcord switch for manual operation during those "stinky" moments, but the fan is not operated via the light switch (although it is wired into the lighting circuit).

In our previous home we had a shower fan/ light over the bath operated by the light switch, and that also proved to be a good counter to mould growth, but I went for "humidistat" in this place because I thought it might help to reduce condensation in other rooms (its a bungalow).

As others have said, the problem is likely to be caused by background humidity. If you want to continue using a humidistat fan you could try replacing yours with the one I have, which as I said above I've been happy with. Its an Xpelair DX100HTA. Your bathroom is about the same size of mine, perhaps slightly smaller, and my fan is in the wall opposite the bathroom door. Might be worth a try.

 

[Taylortwocities]

The pipe work that supplies the shower is accessible under the bath panel, could it be possible to fit a flow switch there to trigger the fan? getting the cable to the fan wont be much an issue, or does it need to be done in the shower itself? do you need to cut in too any pipes? or can it clip on?

There are different types. You’ll see them if you Google
“Water flow sensor”

I have only seen the type thatbplumb into the water pipe. But I believe there are others that just clip on to a pipe. But that’s plumbing and something I try and avoid. Others on here may be able to advise you better on that.

 

[echoes]

I've got a couple of these. One is for a bathroom extractor fan. Needs to be *exactly* vertical.
https://www.rapidonline.com/measurement-specialities-fs-10-meas-copper-bodied-flow-switch-61-1358

 

[Taylortwocities]

@echoes do they just clip in a 15mm copper pipe?

 

[echoes]

@echoes do they just clip in a 15mm copper pipe?

No, sadly. They need a compression or push-fit at both ends. There's a magnet inside the copper section which closes an external reed switch.
I found that if it's slightly off vertical, it can stick 'on'. They do work well though. I keep a spare so I can swap them over for occasional descaling.

 

[mikehammer69]

just fitted an inline fan in my own place

used a current sensing relay and a n/c contactor as i had them lying around

fan has an overrun

 

[JohnW2]

I've got a couple of these. One is for a bathroom extractor fan. Needs to be *exactly* vertical. https://www.rapidonline.com/measurement-specialities-fs-10-meas-copper-bodied-flow-switch-61-1358

I have several of those (some the larger 22mm version) in my house. They have been in service for several years; all continue to work satisfactorily and I have never had to replace one.

However, as has been said, they do have to be 'plumbed in'. I doubt very much that anything similar could work simply by being clipped to the outside of a copper pipe.

Kind Regards, John