Pipe thermostat for fan override

[coopersim]

Because I don’t want to be in the bath with a typhoon style fan running!

 

[Madrab]

For a fan to be effective and keep a bathroom clear of steam and damp and potentially the subsequent mould, the fan should run to evacuate the steam whilst it is being generated otherwise it can condense on the walls/windows, once that's happened then the fan really becomes redundant.

All depends on what the fan is being used for though I guess.

 

[morqthana]

What does it matter if it comes on just if someone enters to wash hands?

Annoying and wasteful.

 

[morqthana]

The pipe to the shower head.

Is that copper?

 

[foxhole]

Annoying and wasteful.

[

 

[dilalio]

Because I don’t want to be in the bath with a typhoon style fan running!

1st time you've mentioned a bath!
Bath still produces steam.
Bogs produce smells.

I've a no window shower room. Powerful fan comes on with light switch.
Stays on until room cleared of smells and/or steam.

I know what I'd rather have than a damp room.

Anything else you haven't mentioned in your OP?

 

[dilalio]

Annoying and wasteful.

And mould and damp isn't a worse evil?

 

[SFK]

How is your knowledge of electronics?
Following Needs a 12v supply and a box to make safe.

Set it to trip relay sending switched live mains to fan as and when pipe is hot.

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Sfk

 

[morqthana]

And mould and damp isn't a worse evil?

If you're getting damp and mould without doing anything in the room apart from breathing you should probably fix the root cause rather than just replace the air with air from elsewhere in your house.

 

[coopersim]

Thanks all I’m going to try and use a flow switch in line to the shower head as I only want the fan to boost when the shower is being used, otherwise I like a nice peaceful bath.

Anything else I haven’t mentioned? Probably, but not relevant to my preferred solution!

 

[morqthana]

Before that, try replacing the pipe stat - got to be easier, and the water to the showerhead has to be over 20°.

The pipe isn't plastic, is it?

 

[coopersim]

No it’s copper. The issue is the stat is exceptionally slow to respond to the change in water temperature, by which time the humidistat on the fan has kicked in.

 

[Harry Bloomfield]

No it’s copper. The issue is the stat is exceptionally slow to respond to the change in water temperature, by which time the humidistat on the fan has kicked in.

I found a similar problem, with a pipe stat I tried to use long ago, in my attempts to get my CH/HW circulation pump, to run on. The thermal mass of the stat, compared to the pipe, meant it could take quite a while to respond. Adding insulation over pipe and stat helps a little, but a much better, quicker to respond is an electronic switch, plus small thermal sensor, a themistor.

 

[morqthana]

My timeguard one switches on within seconds of the hot water starting to flow in the pipe.