On 28/10/2020 16:49, me wrote:
On Tuesday, 27 October 2020 at 22:55:26 UTC, John Rumm wrote:


http://wiki.diyfaq.org.uk/index.php/...d_humidista t



Yes that's how I'd like to do it but a home built one would not pass
inspection.

Inspection by who?

I would have thought that by its very nature, most relay switching and
transient suppression is going to be built up for a special purpose and
hence "home built" in pretty much any case.

Is there a commercial version i can buy off the shelf?

The fan I used and the humidistat were standard off the shelf parts -
but separate.

There are versions that combine timer operation with humidistat if you
want as well:

https://www.tlc-direct.co.uk/Products/ADQT120HT.html

(although quite a bit more pricey).

Part of the attraction of having the functions separated is that you can
place the humidistat in a place where its easy to access and tweak the
settings, without needing to get into the fan itself.

Note that many fans with integrated electronics will specify that
transient suppression be installed to protect them if the circuit also
contains a number of other potential sources of mains transient
including SMPSUs, Dimmers, Florescent lights etc.

For example on the one above:

"EMV regulation
Important indication for the electromagnetic compatibility

Interference resistance according to DIN EN 55014-2 depending upon
impulse form and energy rate of 1000 V to 4000 V. With operation with
fluorescent tubes, switch power supplies, electronically regulated
halogen bulbs etc. these values can be exceeded. In this case
additional suppression shielding activities are necessary (L -, C or RC
elements, protection diodes, resistors)."




--
Cheers,

John.

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