Digitry Controllers

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Suzanne Chudnoff
Posts: 10
Joined: Fri Mar 22, 2013 4:52 pm

Digitry Controllers

Post by Suzanne Chudnoff »

I was hoping someone could help me understand why my GB1 keeps frying. This is the second time the wires in my auxiliary box keep burning up. I had him build me this auxiliary box to make sure that if the relay went bad, it would shut the kiln down. 2 1/2 ago the wires literally melted, and Ron had to build me a new box. Now it's happened again. These are huge wires, the size of my finger. My kiln plugs into a 240 circuit which is wired directly into my breaker box on the other side of the wall. I was told that lightening probably hit it, but we haven't had rain or lightening in Phoenix for months. Then i was told it was a power surge, but the breaker never tripped. I don't understand how the wires could literally melt and burn up without tripping the breaker switch. We don't get power surges here like that. Every breaker was fine. I'm not an electrical engineer, so i don't understand very much about electricity. And i don't know what goes into these solid state controllers or how they are made (which is why i bought a turnkey). So i don't know if there is another component in the auxiliary box that could have caused this. But since this has happened twice, it doesn't seem right. All that i can get from Digitry is that it must have been a power surge that melted down the wire.

Can someone give me an explanation that makes more sense? Thanks. Suzanne
Kevin Midgley
Posts: 773
Joined: Mon Mar 10, 2003 11:36 am
Location: Tofino, British Columbia, Canada

Re: Digitry Controllers

Post by Kevin Midgley »

I've used Digitry controllers for 40 years.
Only problem I encountered was allowing a sending unit's wire to get too close to a kiln and melt resulting in an internal fuse in the controller to blow. Since it was a Little Fuse, it was tricky to track down and find.

What might be your problem is when the electrical wiring in your building was connected to the controller and the kiln. It is not good enough to just tighten the screws once. You MUST wait an hour or more and then retighten the connections. You will be amazed how much more tight the connections can become. AND THEN wait another hour or more and retighten those screws again. During the wait times the copper wire is moving molecularly in response to the initial and secondary tightenings.

I would not blame Digitry for the problem but would look to see how those connections were made.
When the replacement wiring was installed was any of the original wiring, possibly slightly blackened, still have been uses? If so that could be the problem. The wires take a long time to loosen off and cause a problem. A couple of years based on my kiln experience would not be unreasonable to have passed by before the problem resurfaced. If you have followed my above tightening procedures then it might never have happened the first time or the second time.

Also in an effort to reduce the chance of wires burning I tend to not use terminal blocks when connecting heating elements. Instead I use something called split bolts which tighten with wrenches however you need to figure out how to keep those connections electrically safe as split bolts are electrically hot everywhere and must not touch any electrical conductor. If you really don't know what you are doing get someone who does to do the wiring.

Further if your heating elements failed, the panel breaker would not trip.
If you have mechanical relays/contactors, they can go bad particularly on long high temperature holds for as they go on and off fairly rapidly, every time they close their contacts and open their contacts there is a tiny spark which results in there being pits created and eventually the contactor fuses shut (on).
I got rid of my mechanical contactors in favour of mercury relays. They are safe particularly installed correctly and if the electrical box they are in has a metal breadpan underneath the electrical box so as to collect any spilled mercury should one ever fail.
Suzanne Chudnoff
Posts: 10
Joined: Fri Mar 22, 2013 4:52 pm

Re: Digitry Controllers

Post by Suzanne Chudnoff »

Thanks for responding Kevin. My GB1 has a solid state relay in it. And it wasn't the wires in the GB1 controller box that melted. It was the wires in the auxiliary box which is wired to the GB1 box and plugs into the wall that failed. The box was designed to shut down the kiln if the solid state relay ever failed. So maybe the wires came loose from the screws in that box? I never open up the box because there was never any need to.
Kevin Midgley
Posts: 773
Joined: Mon Mar 10, 2003 11:36 am
Location: Tofino, British Columbia, Canada

Re: Digitry Controllers

Post by Kevin Midgley »

Never assume anything with a kiln.
You should be checking your connections for any signs of discoloration regularly.
Turn off the power first!
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