Hi Al I got a quick question about your thermostat, I just bought the same one from Jaycar for my new clone box and I was wondering could you post a picture of how you wired it with the unit open?
The instruction manual is pretty good. See pg 8.
The relay has 3 connection points, NO (normally open), COM (common) and NC (normally closed). The relay connects the COM point to either the NC or NO depending upon the relation of the ambient air temp to the present temp setpoint.
If you want to switch a cooling fan, cut the line (brown) wire in the fan's power lead. Strip the insulation on the two ends you now have.
Connect them to the COM and NC points on the thermostat's junction block.
You can also install the thermostat on an extension cord or power strip. This makes it a lot easier to replace a fan connected to the thermostat later on. You then need only unplug the old fan from the extension cord or power strip and plug in the new one. Also allows you to switch more than one device if you have installed the thermostat in the lead of a power strip. Don't put more than a 5 amp load through the relay contacts.
Also does it need to be inside the box?
Yes, the thermistor (temperature sensing element) is fitted inside the thermostat's housing, so it will sense temp wherever the thermostat body is mounted. It won't sense temps inside your clonebox while mounted outside of it-
unless you modify the thermostat.
Bear in mind that the thermostat unit will work perfectly fine mounted inside your clonebox;
you do not need to do this mod unless you want the thermostat unit mounted on the outside of your clonebox. My clonebox has the entire unmodified thermostat mounted inside the clonebox. Only my bud dryer needed this remote thermistor mount modification, so I could adjust and monitor temperature without opening the dryer while it is running.
If you can use a soldering iron (25watt, no larger), you can remove the thermistor, fit an extension lead and mount the thermistor remotely at the point you would like to sense the air temp.
You can destroy the thermostat you stuff this up, so unless you are competent with hand tools and a soldering iron, stop here!
Keep in mind that this modification will void the unit's warranty, whether you do it successfully or not!
Click any image for a larger size.
1. Remove the battery door and the unit's snap-on front cover per the instruction manual.
2. With a small flat bladed screwdriver, prise out the 4 snap-in tabs holding the display module to the relay circuit board. Only two tabs shown here.
3. Flip the display module over and to the left, using care not to wiggle the 5 conductor ribbon cable around too much- you don't want to break the ribbon cable nor the soldered connections.
4. Remove these 4 screws which hold the display module circuit board to the plastic housing with a #1 Phillips screwdriver.
5. Lift the circuit board out of the housing. The LCD unit may stick to the circuit board when you lift it out or it may stay with the housing. If it sticks to the circuit board and must be put back in the housing, handle it by its edges to avoid fingerprinting the display, pull it free and drop it and its zebra strip back into its position in the housing, with the zebra strip rubber connector toward the top of the housing.
6. Flip the display circuit board over and locate the blue thermistor on the upper right corner of the front of the display circuit board.
7. Desolder the thermistor from the circuit board. Do this
quickly- heat both the soldered connections at the same time and pull the thermistor free with fine-point needle nose pliers, while the solder is liquefied.
WARNING!
- Do not heat the soldered connections for more than about 5 seconds at a time. Applying excessive heat or heating for too long will peel the copper traces off the circuit board and destroy the unit.
- Do not pull on the thermistor's leads unless the solder has liquefied. You will pull up the fine copper traces on the front side of the display circuit board and destroy the unit.
8. Use #20-22ga (small, thin), 2-conductor wire to create an extension lead for the themistor. This can be up to several metres long if you need it to be so.
9. Strip and tin the ends of the 2-conductor lead and solder them on to the copper lands where the thermistor was fitted. Solder the wires on to the circuit board from its back (component) side.
10. Solder the thermistor's two leads to the far end of the extension leads. Cover the connections to the thermistor with individual pieces of thin heat-shrinkable tubing. Do not put heat shrink tube over the blue body of the thermistor, only on the leads.
11. Route the extension lead out of the opening in the thermostat's housing where the junction block for the relay is located.
12. Reassemble the display module by fitting its circuit board back into the housing and reinstalling the 4 small screws. Make sure the rubber buttons are working and not pinched in the housing before reinstalling the 4 screws.
13. Snap the 4 tabs of the reassembled display module back into the relay circuit board.
14. Install batteries and test.
If you have accidentally solder-bridged the extension's connections together, have not made good soldered connections or worst, have damaged the copper traces on the circuit board, the unit simply will not work. Verify that there are no solder bridges on the circuit board nor on the end of the extension lead where you fitted the thermistor. Assure you have not damaged the copper traces.
If the display circuit board has not been fitted properly back into its housing, the rubber zebra strip connector may not make contact between the circuit board's gold contacts and the glass LCD unit, causing the LCD to be erratic or inoperative.
Assuming all has gone well, you can now mount the thermostat body to any surface and put the thermistor at the location you would like to monitor.
