Building and Wiring a Housing for the Tempmate Temperature Controller
Warning! - This project involves wiring dangerous 240 Volt AC mains voltage. If you are not experienced in electrical wiring, do not connect mains power to this device unless it has been verified by someone who is qualified. A threat of electrocution otherwise exists.
The Australian National University have provided a few do's and don'ts duplicated here. It is worth reading as a general electrical safety guide for equipment.
This wiring diagram was found on the aussiehomebrewer.com web site. Credit is gratefully given to the original unknown author. It is accurate and can be used with confidence. Download the original here.
Components
1 - Plastic Instrument box 165 x 125 x 75 mm. Larger is fine, smaller not recommended.
1 - 16mm cable gland, spiral boot optional.
1 - 12mm cable gland, spiral boot optional.
2 - 240V panel sockets HPM 38.
1 - 3 Core Mains Power cable 1.52 mm wire(capable of carrying 16 Amps)with plug.
1 - Heat label and Cool label.
Varios tools - drills, hole saw drill, hacksaw blade, file for holes, sidecutters and screwdrivers for wiring.
Construction
On the front panel, accurately measure the Tempmate rectangular body and mark an equivalent centered rectangle on the instrument box with a pencil. Drill 3 mm holes inside the corners of the rectangle. Mark a horizontal centreline through the middle of the rectangle and mark the centre for the larger holes. Using a hole saw, slowly drill out the holes as shown. Drill very slowly as plastic can grab while drilling.
On the back panel, measure cable glands and power sockets and drill appropriate holes. The HPM 38 socket features a locating pin to prevent rotation. You will need to file a recess into the side of the larger hole. Inspect rear of the HPM 38 socket to match the recess to the locating pin.
On the front panel, use a hacksaw blade holder, cut out corners and protuding sides. (A bimetal hacksaw blade is durable and less likely to break)
On the front panel, use a file to smooth the rough edges back to the marked line. Support thin edge of plastic while filing to prevent plastic from cracking. Remove plastic swarf on the inside filed edge with a knife. Test the cutout by slipping in the controller without the retaining clips, you may need to file out some more if it catches. Also remove the plastic mounting posts near where the retaining clips will be as these get in the way.
Strip back about 300 mm of the power cable (or use another piece if you don't want to shorten your power cable) and make some 100mm wire jumpers, 10 mm at each end is stripped bare and wire twisted. You will need 2 green/yellow earth jumpers, 2 blue neutral jumpers and four brown active jumpers (the photo shows two brown and two red for wiring clarity, you don't have to use red, brown is fine for all active wires)
Dissassemble the 16 mm cable gland and thread it on the power cable as shown, take careful note of the order. The power cable has 100 mm of the outer sheath removed and 10mm stripped off each wire.
Note that earth, active and neutral are never connected to each other, in other words, the green/yellow wire, blue wire and the brown wire are never mixed. They are always separate. Take careful note of this and double check when you have finished building. Connect the green/yellow wire to the GND (ground) terminal on the Tempmate controller, include one of the green yellow jumpers. The other end of the jumper is twisted together with the second jumper and are fixed into the earth connection (green) on the HPM 38 socket. Wire the second socket the same way.
Wire the blue neutral wire into one of the power terminals on the Tempmate controller, jumper the two HPM 38 sockets as shown.
Wire the Brown active wire into the other power terminal on the Tempmate controller, jumper from this terminal to one side of the heat relay and one side of the cool relay on the controller.
Wire the load wire from the other side of the heat relay to the heat socket (note these are shown as red for clarity, brown wire is otherwise fine to use). Wire the load wire from the other side of the cool relay to the cool socket.
Dissamble 12 mm cable gland and feed sensor wire through as shown, connect to sensor terminals, orientation does not matter.
Mount both cable glands and tighten nuts on the inside. Feed cables out to allow controller some room. Maneuver the Tempmate controller into position by allowing the wires to bend. Slide the controller panel mounting clips into place, the springy side of the clips go towards the front. You may have to gently twist the ratchet catches if they don't lock in. Don't overflex it, they can break. Tighten the cable glands so they grip the cables.
At this stage, you should have your work checked by an experienced person before applying power. If you are competant and confident of your accuracy, proceed, otherwise don't risk it. Once wiring is visually checked out, power is applied, electrical safety is checked next, followed by functional testing.
Label the heat and cool outlets appropriately to ensure these are not mixed up.
Testing
Prepare a couple of small bowls for testing the device. Place hot water in one and ice in the other. Set the controller at 25 degrees for the test. Change compressor delay to a minimum (read Tempmate instructions on how to do this). Connect two reading lamps at each outlet. Heat the sensor with the hot water. As soon as temperature is above the set temperature, the cool lamp should switch on (After the minimum compressor delay). Cool the sensor with ice, as soon as temperature drops below the set temperature, the heat lamp should come on (there is no compressor delay for heat). That concludes the functional test.