Wiring diagram for remote humidistat controlled fan with additional manual on/off switch

JoeA · 2026-06-01T20:42:56+0100

I've found a thread that looks quite similar to what I want to do, but not quite. https://www.diynot.com/diy/threads/remote-humidistat-with-timer-fan.624277/

I've got a Soler & Palau TD-250 Silent T inline fan for my bathroom, and would like it to be controlled in two ways.

-Firstly by a using a Manrose 1361 Humidistat (not using the timer function - I will use the overrun timer on the fan) that turns on the fan when the humidity changes.

-And secondly via a manual wall switch that will bypass the humidistat and turn the fan on and off. (And the idea would be that if the fan is already on because of the humidistat, then turning this switch on or off will do nothing.)

The last diagram on the other thread looks almost like what I want to achieve, except I don't want the light involved that will be on a separate switch.

So if I took the light away from this circuit https://www.diynot.com/diy/threads/remote-humidistat-with-timer-fan.624277/post-5668900
Would this then work in the way I want? And actually is the relay actually not needed any more? As the only reason the relay is in there is to stop the humidistat turning on the light?

Thanks

trojanhawrs · 2026-06-01T22:17:43+0100

Yes, you've sussed it. I would suggest a momentary/spring return switch to basically activate the timer, saves it getting left on.

JoeA · 2026-06-01T22:52:06+0100

Ah interesting, thanks! Can you get such a think as a momentary switch and a dimmer switch together on a single plate? Lights on dimmer and fan on momentary switch.

trojanhawrs · 2026-06-01T23:22:47+0100

Something like these mini grid modules. Get the 3 module faceplate, a dimmer module and mounting kit (2 modules) and retractive switch (1 module). There's a good chance you'll need to fit a deeper backbox though, they recommend a 47mm but you might get away with 35 if you've got one already

marktuan · 2026-06-02T13:06:37+0100

JoeA said:
I've found a thread that looks quite similar to what I want to do, but not quite. https://www.diynot.com/diy/threads/remote-humidistat-with-timer-fan.624277/

I've got a Soler & Palau TD-250 Silent T inline fan for my bathroom, and would like it to be controlled in two ways.

-Firstly by a using a Manrose 1361 Humidistat (not using the timer function - I will use the overrun timer on the fan) that turns on the fan when the humidity changes.

-And secondly via a manual wall switch that will bypass the humidistat and turn the fan on and off. (And the idea would be that if the fan is already on because of the humidistat, then turning this switch on or off will do nothing.)

The last diagram on the other thread looks almost like what I want to achieve, except I don't want the light involved that will be on a separate switch.

So if I took the light away from this circuit https://www.diynot.com/diy/threads/remote-humidistat-with-timer-fan.624277/post-5668900
Would this then work in the way I want? And actually is the relay actually not needed any more? As the only reason the relay is in there is to stop the humidistat turning on the light?

Thanks sports games

If the light is no longer part of the circuit, then yes, the relay may well be unnecessary. The relay in that diagram was mainly there to stop the humidistat back-feeding the lighting circuit.

With just a humidistat trigger and a separate manual override feeding the fan's switched live, you can usually achieve the logic you want by wiring the humidistat output and manual switch in parallel. Either one can call for the fan, and if both are active at the same time it won't cause a problem.

I'd double-check the fan's overrun timer wiring requirements, though, as that can affect exactly how the permanent live and switched live need to be arranged.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Wiring diagram for remote humidistat controlled fan with additional manual on/off switch

JoeA

trojanhawrs

JoeA

trojanhawrs

marktuan

DIYnot Local

Similar threads