Hot Runner Diagnostics

Manny Diaz invented the MoldXChecker because customers wanted to know if there was an easier way to test hot runner thermocouples. Manny decided to come up with a solution and take it another step further by checking for pinched wires.

Protect yourself, your hot-half (heater, thermocouples, connectors), your cables and your controller (boards, fuses) by checking for shorts in the hot-half BEFORE plugging it into a controller. This should be done on the production floor and in the tool-room.

“Because if there is a pinched wire in there, as soon as you plug it into the controller, the controller will tell you if there is a pinched wire. But, how’s it going to do it? It’s going to do it violently. It’s going to cause a short, hopefully, pops a fuse on the card. If it does, then it stops there. But, shorts can be fast, violent and sometimes it gets passed that fuse. If it gets passed that fuse, now you’ve probably damaged the card itself, power supply inside of the controller, and hopefully, you didn’t damage any of the thermocouples inside of the tool, or the thermocouple card that is inside the controller. Thermocouples are grounded. If it’s grounded, it’s touching somewhere on this hot-half. It’s touching the body, so if there is a direct short, your thermocouples are going to feel it. 

Let’s see how the MoldXChecker works. Go ahead and plug in your cables and turn the system on. Right away I can see that zone #1 is at 172 ohms, #2 176 ohms (probably drops), 169, 127, 17 (now seeing manifold heaters), 25 (probably a sprue), now I see zone #9 is not there so I have an open (either no heater or a bad heater), nothing on #10 or #11 so it’s probably just an 8-zone. I can confirm that by looking at the thermocouples. It’s very hard to determine if you have a good thermocouple because it changes ohms just by touching it. This tool shows ohms on zones 1-9 and not on 10, 11 or 12; so it’s an 8-zone.”

Explanation: MoldTrax teaches trainees to regularly check and record the ohms on heaters. If they see a trend or spike upward, that is a sign that a heater is going bad and should be replaced before going back to production.

“If I was doing that with an ohm meter, this is what I would have to do. I would have to know the wiring diagram and then manually touch the matching pins to get an ohm reading. If I want to check for a short, I would have to put one lead on the hot-half, and then manually touch each pin. With the MoldXChecker, as soon as I turn it on, I immediately see what zone is shorted. I know this is an unsafe hot-half to plug into a controller because it’s going to blow a fuse. And, it’s going to do damage. Whether it’s damaging just the fuse, damage to the whole hot-half, doing damage to you - just because it’s grounded doesn’t mean you won’t get shocked.

Now that you know exactly what zone is shorted, you don’t have to check every zone once you open up the hot-half. Just go to zone #9, find that wire, put some shrink sleeving on it, put it back together again and your back out in production.

Had you not done this, and plugged it into a controller, you would have to re-test this thing all over, looking at all the wires and thermocouples because you don’t know what you could have damaged.”

Fast Heat's MoldXChecker®  Hot Runner Mold Testing System. 

MoldXChecker®
List Price:  $2,100 Includes Shipping

The MoldXChecker® hot runner mold testing system prevents line-down situations by quickly identifying shorts, opens, and resistance values in heaters and thermocouples. Invented by a maintenance professional for maintenance professionals!


  • Be Safe! - Check for dangerous and destructive shorts BEFORE plugging your tool into a controller, both on the production floor and in the tool room.
  • Save Maintenance Time! - The old way checking for shorts and measuring ohms for each zone takes forever.
  • Ensure 100% Accurate Testing! - No more skipping steps, getting false readings or searching for shorts.

Copyright 2019 Fast Heat, Inc.

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