TC/EA furnace troubles:

The background:

Probably more than a month ago now we most recently shut down the TC/EA after a series of analyses of water for hydrogen isotopes. Alas, I was not present during the power down (that'll never happen again!), but am told that at about 500 degrees C the system cooled rapidly. This I suspect is related to a crack that developed in the ceramic reactor tube that I discovered later when taking the TC/EA apart. This has happened before with no long-term ill effect to the TC/EA.

This morning I tried to power up again for another set of water analyses. There's a brand new reactor in the TC/EA and everything is leak-tight. Ordinarily at this point, I just turn on the TC/EA and warm it slowly to the full temperature that we use to water analyses: 1450 degrees C.

I did recently shift the jumper on the transformer to higher voltage, because the TC/EA was having difficulty getting all the way to 1450.

The problem:

The furnace is not warming up. The CG oven is warming fine. I've switched on and off the system and rechecked for leaks with no change. I moved the jumper back to where it had been with no effect. The trouble-shooting guide only offers the further suggestion that it could be a bad thermo-element switch. I took the aluminum cover off the furnace to see what I could see.

The questions:

1) Is there a visual way to tell if this thermo-element switch is bad? Or do I just order a new one and hope for the best?

2) Is it possible that the heating element itself is broken? Is there a simple way I can determine that? Where/who is a good supplier for an element should I need to buy another?

3) This is what I saw when I took the cover off (below). The insulation crumbled if I so much as looked at it and the blue wire was not fully seated in the screw holder. Could this be the source of my trouble? Obviously,  I don't want to do a bad repair here, but I have to do something. Any suggestions?



4) Final question: For all the digging around it looks like I'll probably have to do, what do you think the chances are that I can get this repaired in a day or two?

Thanks for all your help, everyone!

~Penny


More information:

I've removed the element and noticed a chip in the side of it. While I don't think this is the cause of the problem noted above, I do think it could be a problem. Any thoughts on this?




In the end, I think that the major cause of the touble is that the blue wire broke away from the terminal block. Both the red and the blue wires will need to be re-insulated. What is the best way to do this? Would it be easier to simply replace the entire wiring piece, rather than trying to re-insulate those two wires? Does anyone know the part number for this?

Also, any suggestions on how to remove the ends of the red and blue wires from the terminal block? They seem very fused in there and I can't get the screws to turn.



Thanks again,

~Penny