Fan controlled by light switch and Humidistat

[dimmer]

How would this work (Would it)

Idea is for Humidistat (Manrose 1360) to control fan during the day

Would like the fan to also come on when light is on

Would you connect light switch to fan as usual

and also connect Humidistat to fan as usual

This would mean though that the fan would have two switch live inputs
which could be live at the same time i.e light on and humidistat on.

Though I guess if the fan comes on when the light is on the humidity may not reach levels to trigger it.

But if the switch lives are connected will the light come on when the humidistat does?

 

[ricicle]

You will need a relay to make the system work how you require.

 

[dimmer]

Thanks for the reply

A relay, could you expand please as I don't know how these work.

 

[ricicle]

Using a relay means that the switch lines can be kept independant from each other but still both can switch on the light.

The light switch would energise the relay coil and loop across to the relay normally open contact. On the other side of the contact would be connected the fan line and the switched line from the H/stat. Thus the light switch would energise the relay and switch on the fan or the H/stat alone could bring on the fan without energising the light as the relay contact is still open (light off)

 

[dimmer]

Thanks that is really helpful.

Could I just bother you for one last question.
Could you suggest an appropriate relay.

Many thanks

 

[ricicle]

Example

You will need the base as well.

 

[dimmer]

Many thanks

I really appreciate your help, but I think I will have to do some research into an idiot guides to relays

I don't understand that at all, and don't know what a base is.
I will look for wiring guides.

Was I correct thought that 2 switch lives would mean that if the humidistat came on it would switch on the corresponding switch live light?

I would not mind if the light came on when the humidistat was working

would that work / be OK i,e could you have two lives to a fan, it won't be hazardous.

 

[dimmer]

I have been thinking about this and have draw a little diagram.
I wonder if I need a relay
I think the switch lives may not be the issue after all

The Humidistat has a live in and a live out
The live out goes to live on the fan
so when humidistat want to turn on it will send power to Live

The live from the humidistat will turn off once humidity reduces, so it does not go to switch live

The switch live for the light goes to SL for the fan and timer will switch off
Am I correct?

View media item 51999

 

[EFLImpudence]

No it won't work.

The switched live has to be 'triggered' to operate the fan.


You can buy fans with an integral humidistat which are cheaper than your humidistat.

 

[dimmer]

Ah Yes of course, Bahh

Going to have to work out how to wire a relay.

Looked at some today but I dont know where to start

If anyone would be so kind, how would you connect this all together so a relay would allow the fan to be controlled by the humidistat or light switch

Thanks

 

[ban-all-sheds]

No need to mess around with relays - just replace the existing light switch with a double-pole one so that there's no link between the fan switched live and the light switched live.

 

[dimmer]

I am still curious about how to wire a relay
I bought one but can't understand how to wire it
I have taken a few photos if somebody could let me know how they are wired , that would be great
Just to recap


Fan controlled by Humididtat
Fan also controlled by light switch


I plan to use BANs method though, I think this is right (Perm live missing from supply to isolator)
View media item 52341 View media item 52339 View media item 52340 View media item 52342

 

[ban-all-sheds]

I am still curious about how to wire a relay
I bought one but can't understand how to wire it
I have taken a few photos if somebody could let me know how they are wired , that would be great

The photos don't show the diagram on the side of the cover.

2 contacts will be for the coil, and 4 (or 6 if it's a changeover relay) will be the contacts. The terminals on the base are numbered, and on the side of the relay the schematic will show which is which, but I'm pretty sure that 2 & 7 will be the coil, 1 & 8 the commons, which will pair respectively with 3NO/4NC and 6NO/5NC.

 

[dimmer]

Thanks very much BAS

I have drawn a picture of how I think they work (I need to see things visually to grasp them.

Would this be correct

I presume separate switched inputs to get full functionality
So.

No power = nothing

Power to 1 would send on to 4 (NC) and would light lamp (or what ever)
coil not energised

Power to 2 and 1 Coil energised and pull in contact 3 (NO) would become live and light lamp

Power to 2 1 8 coil closed so 3 and 6 would come on.

Is that correct?

How would this enable switching heavy loads.
I thought a relay was a switch which allowed a big current using device to be switch on with a lower rated switch

Basically how does a high amp supply get through

The load on 2 is small so a low rated switch could be used

A high current can flow through the commons, and the relay 'directs it'
Is that right?

Hope that make sense

Thanks
View media item 52437

 

[dimmer]

Just give this a little nudge back up.

Would be interested if anybody would care to comment on the relay drawings at the end of the post.

Am i heading in the right direction.
Thanks