Kiln tripping breakers
 

Hi guys:

I know, the title sounds like a wild rave LOL. I'm pretty sure I have a short somewhere in my kiln, but am not quite sure what to do.

As soon as I turn the kiln on and start a garage/annealing program (if the kiln is plugged in and on, but not running a program everything is fine), it blows the breaker and I have to go down in the creepy, spiderweb/shed snakeskin basement to flip it back on. I have it sharing the washing machine's electrical socket as I know that is a dedicated line which is rated for the same amt of amps the kiln pulls (and no! I never run both at the same time, and they are the only 2 appliances on the line). The washing machine works fine.

I've checked Paragon's info, and this is the closest to my prob that I can find:

Circuit breaker trips or circuit fuse blows.
■ Does the circuit breaker/fuse shut off immediately after the kiln is
plugged in or turned on?
 Breaker trips immediately after the kiln is plugged in.
The kiln plug or wall receptacle has a short-circuit. Check the plug for discoloration and heat damage. Replace the
cord and wall receptacle when the plug shows heat damage.
 Breaker trips immediately after the kiln is turned on.
The kiln has a short-circuit. Unplug the kiln/disconnect the power, remove the kiln’s switch box and check for disconnected
wires. Keep the kiln unplugged until you have found the problem.

I checked and the plug and socket look fine, so I'm thinking short circuit somewhere. What's not clear to me is when they state: Breaker trips immediately after the kiln is turned on., do they mean when I flip the switch to the on position? Or start a program? Cause as I said above, if it's not running a program and pulling power, it's quite happy to sit there and show me the ambient temp. The troubleshooter doesn't discern between just turning the kiln on, and turning on a program, so I'm unclear whether there might be a difference and if this is something I might be able to deal with on my own.

Any suggestions? Or should I just contact them?

Thanx :)
Alli

I'm not sure how to be helpful since I don't know what you are comfortable doing.

With your kiln, one way to describe the situation is that there are two circuits: one is low voltage (this is simplified, I mean it is DC and not AC, but that is beyond the scope) and one is high voltage (normal AC voltage). The low voltage part runs the programs and the high voltage part runs the heating coils. The two work together with the relays, which means that the low voltage part sends a signal to the relays, and the relays are the on-off switch that connects the electricity coming from the outlet to the heating coils.

The Paragon information is more for a kiln that does not have a digital controller. Once you turn on the switch, some electricity should be going from the outlet to the heating coils. With the digital controller, that does not happen until you start a program (unless the relays are stuck, which does not seem to be the case in your situation).

So, a guess to what is happening is there is a short on the outlet of the relays, and instead of the electricity going to the heating coils when the program is started, instead it bypasses the heating coils and goes directly to the neutral or to ground.

One thing you might do is, WITH THE KILN UNPLUGGED FROM THE WALL SOCKET, remove the cover from the controller and see if anything is loose. You may see some black burn marks. If you see something like that, maybe you can take a picture and post it and someone might be able to provide the next step. Also, please provide the model of your kiln, because that will let us look up the schematic from the Paragon website.

The relays are probably little boxes, maybe 1" x 3/4" x 3/4" with two thin wires and two thick wires. The problem may be at one of the thick wires. You might be able to trace one of the thick wires to the cord that plugs into the wall. The problem should be with the other thick wire, which you might be able to trace to the heating coils.

Check the breaker itself - the screw (or what is used in the breaker to hold the power wire) sometimes may get loose by itself, the contact becomes weak and the connection spot starts to heat, burns (brownish visible signs of heating appear on the end of wire connected to the breaker and the contacts of the breaker) - the breaker will not function properly in this case and will shut down when more or less powerfull device is plugged in the line controlled by it.

Please do not forget to switch off the main breaker if you have it before you go to the "box full of breakers" with your screwdriver to check and tighten the joints.

Easy test - switch an electric kettle or iron (anything consuming 1.5-2 KWatts) and see if it functions properly. If the breaker shuts - the problem is not inside the kiln.

From what you have said about the washing machine running OK on the same circuit breaker this tells me the problem is inside the kiln.

The fact that it will tell you what the temperature is inside the kiln indicates that the controller is OK.

It is only once it tries to start heating that it trips the circuit breaker and that does mean the problem is in the "heating element" part of the kiln.
1) You can unplug it from the wall and open the kiln and look to see if the heating elements are too close together where they go inside where you would put your glass. It is not likely but possible that the heating elements got distorted and are just too close together.
2) Again with it unplugged you can look through the holes in the controller with a flashlight and see if some critter crawled into a spot it shouldn't have and has become part of circuit. Look for charring / burnt marks. Dust can also collect inside these things and a good vacuuming can keep that from becoming a problem but once dust starts causing problems removing it usually wont fix it.
3) The relays that control the heating elements do die and can be kind of easy to replace if you have D I Y skills but might be better left to the technical types if you are not handy with screw drivers and such.

I am inclined to think it is a relay gone bad from the symptoms you have described.
Contact the maker if you can. Sometimes the things have sockets and replacing them can be as easy as unscrewing a panel and pulling one out and sticking the new one in kind of like changing a light bulb.

Is this a recent development?

Do you have anything else on the breaker?
Is the amperage on the breaker greater than the draw of your kiln?

Ok, I'm an idiot.

Was warming up the kiln the other day (yes, this is very recent) and wasn't in the room when I thought I heard something. Didn't see anything when I walked back in and assumed it was my idiot cats. The more I think about it now, it sounded like a pop. And right after the kiln started tripping the breakers. *head slap*

Here is an article that I wrote for the Paragon website that might help you.

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com

FINDING AN ELECTRICAL SHORT IN A KILN

If the circuit breaker trips or a fuse blows when you first turn on the kiln, unplug the kiln and look for a short. Here is where to look:

Remove the main control panel or switch box from the kiln and look for a pinched wire. It will be under one of the switch box mounting screws. A screw that breaks through the wire insulation will cause a short.

A cord set connection that touches the kiln case can burn and cause a short. This will shut off the breaker when you plug in the kiln. Look near the cord set for the damaged connection or burned cord set insulation.

Most kiln brands have porcelain insulators under the element connectors. The porcelain insulators, which look like small mushrooms with a hole in the center, must be pressed all the way into the heat shield. A porcelain insulator sticking out from the heat shield can cause a short.

The excess ends of the element that extend past the element connectors must be cut off. Bending the twisted element ends to the side or leaving them sticking out straight can cause a short in the kiln's switch box.

Do not use electrical tape inside the switch box. A wire can short against the kiln case when the tape burns off.

Make sure wire connections are tight. A loose connection can overheat and burn off a wire, which can short out against the kiln case. Look at the kiln’s element connectors. If one is missing, it has probably burned off and fallen into the switch box, which can cause a short.

We had ceramic stand offs in our high voltage circuits in the radars I worked on in the Navy.

There was this one failure on a radar that was 40 years old where the ceramic had a hairline crack that eventually developed a rust line from the screw in the center of one side through to the screw in the center of the other side. Took us five straight days to find it because it just was not something you think of looking for.

Sometimes a pinched wire's insulation will be fine for tens of years and then one day it just gets old enough that it starts to arc over and then sometimes a transistor just quits working the way it should and starts shorting out.

Hope you can fix it now Alli. When that happened to me I heard a pop as well. I had to replace the infinity switch. Hasn't happened with the new kiln and controller yet but they sent me some parts for when it does...LOL