Slightly OT:Wiring a Thermocouple for home furnace

You should be able to find a manual on the internet once you know the manufacturer and model no. You will need Type K thermocouple wire and possibly Type K connectors to connect the probe to the electronics. No sense guessing, just wait for the manual.

You will note that the wires are different colors. Match the color of the wire to the terminals on the controller that the wire hooks to and you should be fine. If you get them backwards, the controller will just drive to a limit and when you reverse the wires, it will start working right. The voltage is very low and won't hurt anything if it is backwards.

-- There are more Democrats on the Calif. Special Election than Republicans! Go count if you don't believe me! Bob May

I have looked all over the web for info and will check a few more sources. I have also posted pics and an explanation on my website

-- Steve Worcester

...

I looked at your website and the auction you mentioned

1. If your K thermocouple is color-coded yellow and red, (see
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   attach the yellow to TC+ and the red to TC- on the back of your XMTD-3011
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   it isn't color-coded, attach it either way and then figure out as noted later.
2. Attach an ohmmeter from OUT NC to OUT Common, or from OUT NO to OUT Common. (The bottom left terminal is OUT NC. NC stands for normally closed. The OUT relay is closed if the unit is unpowered or if setpoint is met.) You could use a battery and light rather than an ohmmeter if you prefer, or just look at the front-panel OUT indicator light, but it's a good idea to verify early on that the indicator light actually tracks operation of the OUT relay.
3. Attach 120VAC to the 120V terminals of your XMTD-3011. (For testing, it probably would be reasonable to have a 1A or 2A fuse in series with your AC cord.)
4. Dial the setpoint down to near-ambient. Verify that OUT NO closes (connects to OUT Common) when setpoint is above ambient, and opens when it's below. If this doesn't work perhaps reverse the thermocouple leads.
5. Unplug power. With power removed, hook the contactor's control winding, A1 - A2, in series with 120VAC, OUT NO, and OUT Common. For example, Black AC wire to OUT NO; a red wire from OUT common to A1; White AC wire to A2.
6. Plug in power. Again dial up and down through ambient temperature. The contactor should pull in and drop out appropriately.
7. For powering the element, attach Black AC to L1, White AC to L2, and element to T1 and T2. (Your contactor might or might not switch L2-T2; see contactor picture at left hand side of picture near the middle of
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   for example. You could test it with an ohmmeter with nothing else attached.)

For debugging you can connect a 75W light bulb across T1 and T2 (instead of element) and try controlling your furnace at 125°F.

-jiw

Thanks a bunch. Simple English instructions.

-- Steve Worcester