Phil's HERMS Brewery

240vac is very dangerous and you should never mess with it unless you're confident that you won't kill yourself.

Most of the electrics are housed in a waterproof box. Any connections outside this box are waterproof in their own right. With all the water and wort flying around on brewday this is a really good idea. I originally mounted the controls on an aluminium plate with the connections exposed on the back but I popped several PID controllers by splashing them so I fitted the waterproof box.

The way I connected my electrics up, I only break/make the live feed to the element with the SSR. To be sure that the element is completely isolated you could (and arguably should) also break/make the neutral with a second SSR.

Here's a diagram showing the system connections. It's really very straight forward but if you have any doubts get an electrician to do it for you.



The SSR I use is a Tyco SSR-240D25 which I bought from RS. The spec is in the name; it's an SSR used to switch 240 vac, it's switched by a DC voltage and it'll switch 25A. The element in the heat exchanger is a 2.4kw unit and it'll draw 10A max, so the SSR is well able to switch it on and off safely.

The thermocouple is designed to be attached to a pipe with an attached jubilee clip. It's a K-type thermocouple and I have attached it to the pipe exiting the heat exchanger. This is what they look like (in the RS catalogue).