Almost there!

I ran into a problem with how I wired the limit switches.  I used unshielded wire, so, the electromagnetic field coming from my motor killed my control board. I bought a new board and re-did a lot of the work I had done, replacing a lot of the wire with shielded wire. Once the limit switches were done, the thermonic controls needed to be rewired to get them to work.  I thought I was about ready to run some plastic through this thing so I rigged up a scrap piece of aluminum to the stationary platen.

 After I had that piece in place I was planning on shooting plastic through the hole in the center. I was about to pour some plastic in the hopper when I remembered that the machine needs cooling water to keep plastic in the hopper from melting before it reaches the screw. I hooked up the hoses to my sink to provide temporary cooling and right away found a water leak coming from my machine. I hoisted the injection unit once again (I'm getting good at this!) and found the leak  in the center of the heat exchanger on the bottom side. The hole is about 1/2" in diameter and seems to have rusted through from the inside. You can see the heat exchanger below, it is the grey tube on the bottom of the compartment.

 I am trying to decide how to fix the problem, its going to be a major pain to fix it in place because its such a cramped space but trying to remove it could lead to more problems. Taking apart a 40 yr old plumbing job does not sound fun; specially, since I can't buy replacement parts if they break in the process.

While looking at the cooling system I saw that at one point the heat exchanger was hooked up to a valve that only flowed when the oil reached a specified temperature. It looks like this valve wore out, so, they just bypassed it and now the water flows all the time. This made it so the oil never overheated, but it also was never allowed to reach its designed operating temp. To fix it, I ordered a small temperature controller on ebay called a REX-C100 for just $15 and free shipping. From the data sheet, I should be able to program it to control the temperature and send an alarm to my main control board if it gets too high.

If I am happy with this little unit, I might replace all the temperature controllers with it. I would need at least 5 more of them if I did do it; 3 barrel heaters, 1 nozzle heater, and one mold heater/cooler. I do not trust the old controls and they don't show a temp reading so I would like to get rid of them if I end up getting this machine to work.