Temperature control is one of the most important factors in home brewing consistently good beer. The following is a guide on how to wire up an STC-1000 Digital Temperature Controller so it can be used in conjunction with a fridge and a heat belt / heat pad or some other warming device.

The temperature controller comes as a panel mount unit, meaning it requires some wiring and housing in a box.

IMPORTANT: As you're dealing with mains electricity, you REALLY REALLY should either have it done by someone qualified, or at least have them check it over before you plug it into the wall.

Disclaimer: It's your responsibility to confirm you've wired your particular device correctly. If you're even 1% unsure, get an electrician to check it over for you.

The plan

My set up has the temp controller housed in it's own box, with two flush mount power sockets for plugging in the fridge and the heating device. In my opinion this is far better than hard wiring it into the fridge (which you can do if you want). It means if the fridge dies, or you decide to upgrade to a chest freezer, you can simply plug in the new one. It also means you can use the temp controller for all sorts of other applications that you probably haven't even considered, such as plugging in a heater and thermostatically controlling a bedroom, or using it to accurately maintain a temperature in a slow cooker.

You can get all the bit and pieces you need from Jaycar.co.nz or any other electrical supplies / hobby store. Aside from the temperature controller, you'll need the following items:

• 1 x Jiffy box (big enough to house the controller and with enough room for the wiring and power sockets. I used an HB6012 from Jaycar.
• 1 x 3m power / extension lead. You can also snip off a power cord from an old dead appliance. Just make sure it's rated for 10A or higher.
• 1 x wire joiner / terminal block with 3 connections. This is to help with the wiring where you effectively need to split one wire into 2 or more.
• 2 x flush / panel mount power sockets. For plugging in your fridge and heat belt.
• 2 x rubber cable glands. For securing the power cable and probe cable.

Let's get started

1. First thing you need to do is to cut out the openings in the jiffy box. You'll need to create:

• a rectangular opening for the temperature controller, 
• two round openings for the panel mount sockets (I did them at the rear, but you could also cut them into the side if you prefer), 
• a round hole to feed the power cable through and, 
• a smaller hole for the temperature sensor.

Carefully cut the protective casing around the end of the power lead to expose the three wires.

Carefully strip the ends off all of the wires

Push the power cable through the hole you made for it and connect the wire ends to the wire joiner.

For the rest of the wiring, it's best to study the wiring diagram that came with the unit, and look closely at each of the following images (Note: the temp controller and power sockets are upside down in these shots since the box opens at the bottom):

Blue Wires:

Brown Wires:

Green Wires:

Wiring diagram:

Front view

Rear view