Humidity Controller

[TonyE]

In an attempt to duplicate some of the Salami recipes on Len Poli's fantastic site, I have recently purchased a Humidity Controller from a company called Two Wests & Elliot Ltd to go with the Humidifier I purchased from e-bay.

When the Humidity Controller arrived it clearly stated on the box that it was 115V model, when I contacted the supplier, they informed me, that it could be used at 240V, I strongly disagree with this advice, as this device does not contain an auto-switching power supply unit. I am returning the unit to the supplier for a refund.

Does anybody know where I could purchase a 240v Humidity Controller, or is it back to e-bay

[dougal]

Well, Tony...
I checked their site and found this
http://www.twowests.co.uk/TwoWestsSite/product/COHC.htm

The price of �33 ain't too bad at all.


As regards the voltage, I doubt that's actually too much of a problem - let me explain -

What is in the box is actually likely to be an unpowered switch. It'll have a sprung action, which will vary with different humidity. By turning the knob, you'll change the preload on the spring, and hence the humidity level at which the switch operates.
In principle, its rather like a thermostat based on a bi-metallic strip.
The operation of the device isn't going to require any power.

You would be asked for a much, much higher price for an electronic humidity *measurer* and controller.
Here's an electronic DIY project I found
http://www.ludens.cl/Electron/hygro/hygro.html
The sensor alone has a cost price of about �20...

OK, so if your thing doesn't need power to operate, where does the voltage spec come into this?
A: two places! Firstly, the insulation safety for mains to protect people should be rather better than that required simply to protect low voltage equipment from itself! And then there's the rating of the switch contacts - this is more a limitation on current than voltage - how much power can they handle? (One can go on to question whether the load is inductive or resistive, but no matter for this.)
My suspicion is that the item is made in the USA principally for the US market. Someone has found that it works fine with the 240v UK mains and is importing them.
Frankly, I'd expect it to work fine with 240v, and a low power device like a humidifier.

HOWEVER there *is* a problem that I foresee with your intended design.
You appear to be bringing 240v mains inside the fridge, and exposing mains voltages (switch contacts and terminals) in an environment that may at times be rather wet. Particularly beware condensation dripping from the cold element (ice compartment?) in a 'warm' fridge. (Yup, its dehumidifying!)
So shield your mains powered kit from water dripping or splashing!
And run everything through an earth leakage circuit breaker (RCD) for safety.

I'm hoping to use a little 24v Maplin fogger to get round the mains danger problem and to minimise the power being switched by the "Rittal" Hygrostat (a �60 RS item) that I picked up fairly cheaply (on eBay actually) and which operates as I have described above.

Its worth noting that some Hygrostats don't have "humidifier" connections - just *de*humidifier connections. A changeover switch with access to both poles can be used either way.

[TonyE]

Hi Dougal

Many thanks for your very thought provoking reply, it shows how much I know about humidity controllers. I was hoping to connect the mains in at one end, and the Humidifier at the other. The diagram that came with the unit, looked considerably more complicated. In hind sight I think you are spot on with your assessment i.e. It is almost certainly manufactured in the U.S. and may well be safe at 220Volts (U.K.)

My inspiration for this was good old Len Poli,s Web site he had converted an old fridge into a humidity cabinet, very simple and neat. Something I was hoping to do myself. However I do take your point about electrical contacts in a humid environment. I shall print out, and keep a copy of your reply, while I decide what to do next

Once again many thanks for your reply


Regards - Tony

[dougal]

Tony - you may be interested in the alternative possibility of controlling humidity with a saturated brine (wet salt).
I recently described that method here
http://forum.sausagemaking.org/viewtopi ... 6836#16836

As a fellow novice, I'd be delighted to learn from whatever you and others may have learned about the subject.
I'm happy to share what I know.

BTW the basic Maplin fogger does seem to splash rather more than I like, and which I haven't yet properly tamed.
I have a feeling that wet salt combined with very gentle air movement may turn out to be the simplest and most effective method...


I wonder if it would be best for Admin to move this thread to a more appropriate section than "Chatter" ?

[TonyE]

Wow Dougal

That is one heck of an e-mail you pointed me to, I have printed it an will read with interest. I think in the short term I will try the following.

1) As soon as we replace out Fridge at home, at any time now, I will keep it in the garage, if I can find the room for it. And use it as a curing cabinet.

2) I will wait until the weather cools down a bit, probably another month or so, just to avoid spoilage.

3) I have purchased a Humidifier from e-bay, and I have a combined thermometer and humidity meter. I will put the whole lot in the fridge, monitor temperature and humidity, and manually control it.

I would prefer to do it using an automated process, I will have to work on that idea.

I have attemped Salami twice, the first time I used my Bradley smoker, and aged the Salami for about 10 weeks - fantastic result.

As the summer approached I attempted Milano salami without smoking, and ended up throwing the whole lot away, as I had some very dodgy mold growing. I suspect it was getting a bit too warm.

Thanks for all your help

Regards - Tony