neilestrick

Thank you for the great photos! You've got 3 different issues here: 1. ETH error code. This code happens when the circuit board in the controller gets too hot. It shuts down the firing so the board isn't damaged by the heat. The error code happens when the kiln room isn't properly vented to remove heat. I see it a lot in schools where the put the kilns in little storage closets that have poor air flow. It's virtually impossible for this to happen to a wall mounted controller because it's not close enough to the kiln to get hot. So that means the controller freaked out for some reason. 2. FTH error code. Could be anything. Do a paper test and see if all the elements are heating. That will also tell you if all the relays are working, at least at low temps. Failing relays can stick at high temps, though, so the kiln shutting off at 1898F could definitely be from a relay sticking once it got hot. 3. The controller turning on and off at 300F. There's no reason for this to happen if things are working normally. So either the controller is dying (consistent with the random ETH code) or there's a power supply issue. The power supply could be simply a loose wire (check all wiring connections) or a bad transformer (the thing below the relays-yours is pretty corroded), or possibly a bad fuse holder. Wiggle the wires connected to the fuse holder and the fuse holder cap and see if the controller shuts off.

The kiln controller is not mounted on the kiln? Post some pics of the whole setup.

Is there a lot of corrosion on the circuit board? A 30 year old controller could definitely be failing.

The relays and thermocouples will not cause the controller to shut off and restart. If there's a problem with the thermocouples or relays then you'll get an error code. Sounds like there's a power supply issue, either from your house's electrical service, or a bad connect in the control box, or the transformer in the control box is flaking out. Or, the controller itself is dying. When you got the ETH code (control board too hot), how hot was the kiln?

When you say it shut down, do you mean the controller actually turned off and then back on, and no error code?

Your post mentions both Fth and Eth? Is one of those a typo, or id you get both codes? You should not get an ETH unless the kiln was at high temps. The FTH could be caused by a bad relay, but at low temps that should only happen if you have a kiln with multiple zones, and the way you're describing it this only has one thermocouple? It's also possible that your 32 year old controller is dying. And yes, some thermocouple designs require bending it.

The bare copper jumpers are an odd way to do it, and not necessary. Instead, just leave the element pigtails long, bend them to meet up and overlap about an inch, and put a connector on them.

The cracks shouldn't affect heat loss. When making elements, they'll need to know the diameter of the coils and the resistance of each element. Where this kiln gets more complicated is that you need the straight section in the middle of each element rather than one continuous coil. I would measure the resistance of a few of the individual wall elements (top, middle, bottom) and see if they're all the same. They may or may not be, just depends on how they did it. Also measure the resistance of the floor elements. They may have the same resistance as the wall elements but they're just spaced differently, or they may be a different resistance. Since they're all wired up in series, the elements have likely worn at about the same rate, so even if they're no longer reading like new, whoever makes the elements should be able to math it out to get accurate numbers on what they should be based on the ratios they're reading now. To get the straight sections made correctly, I would send a wall element and a floor element to the maker. Once you measure the resistance of all the elements you can math out the amperage draw and see how far off it is from the information on the serial plate.

A wiring diagram sure would be nice! Can the manufacturer get one to you?

See if they sell the thermocouple without the block. It'll be cheaper.

Yes, figure out where the hum is coming from. Elements humming is normal. Relays in that kiln should be quiet, as they are not very large.

Do the wires coming out of the block box go to the control terminals of the main contactor, or are they load wires- if it is indeed a high limit shutoff, is it shutting off the control wires or the power wires?

Is that the thermocouple wire connected to it as well as the power wires? I'm thinking it's the brains of the controller. Maybe it has the transformer in it, too. Does the keypad have a circuit board attached to it?

In basic terms, any sort of switch that can be cycled on and off is a relay. In this situation it's not a pilot relay because it's not cycling every time the main relay does. It's just a safety switch. It stays on as long as the door is closed. It is possible that it is failing when the kiln gets hot, but you'd need to test it when the failure occurs.

The bent TC is standard on a lot (all?) Evenheat kilns. They way they mount them is very solid, and the bend doesn't affect the performance. @Bill Kielb I found one here in my shop and it's not 8 gauge. It measures out to be 14 gauge, which is why it can be bent like that. Beads only measure about 1/4" across and the protection tube is much smaller than what you'd find in an L&L or ConeArt.

I don't think that tip looks bad at all, but it's possible that the weld has split, which would cause erratic readings. Be sure to check that one of the TC wires hasn't broken under the screw in the porcelain block. Also check for any splits in the wire where it goes around the metal shield. The Evenheat thermocouples are narrower than the typical 8ga ones used by L&L, Skutt, and others. Buy it directly from Evenheat to make sure it fits.

How many of these are in the kiln?

Can you post a pic or two of the open control panel so we can see what's in there? Most of us on here have probably never seen that brand of kiln.

Pilot relays are typically only used in kilns with large contactors, like 50 amps or more, where the controller doesn't have enough output to switch something that large. Can you post the info on the serial plate- volts, amps, etc? I have seen brand new relays/contactors fail right away. If it's not due to the contactor itself being faulty, then you want to replace the power wires that connect to it, as they may be overheating and causing the failure. In my experience it's almost never the control wires.

I run about 15 glazes in my studio, and they're used on at least 4 different clay bodies, so I won't be any help in terms of how they fit on the 630 specifically because I don't try to fit any of them to any one body. But I will post if there's any difference in appearance or behavior.

So normally there's a loud clunk throughout the firing as the contactor cycles on and off? But when it's not working you only hear a soft click? Without a wiring diagram it's hard to say, but it sounds like a sticky relay, as they often stick when they get hot (from a combination of the current flow and the heat of the kiln), but then they'll work again as they cool. Is the contactor switched directly by the controller, or is there a smaller pilot relay that works between the controller and contactor? A small pilot relay would account for the quieter click. Of course, that wold mean that the big contactor is failing periodically, despite you changing it. Any chance you can post a wiring diagram? The manufacturer's website was no help. I did fine this little gem on their venting page: "The kiln itself will not produce any fumes. Most material used in hobby ceramics are safe and produce minimal fumes. Certain materials like lustres and ceramic transfers can produce more harmful fumes when fired in quantity, but are rarely used in school/hobby kilns." Lots of issues with that statement. Apparently they have only ever fired their kilns empty!

@Frenchpotter I think this is just a US-Europe difference thing. Sounds like the 6mm difference between the 350mm bat and the 14" head is just too much for it to fit. Unfortunately there's nothing you can do to modify the head. Can you exchange the bat system for the version that uses pins? Even if the pins don't line up perfectly, you could drill the bat to make them fit. Another option may be to put a thick 350mm bat onto your wheel head using pins, and then put the bat system onto that.

Post a pic. It's easiest to get the same size/shape thermocouple that you already have. Most likely it's a type K, but they come in lots of different shapes and sizes. If the temp is flickering like that, I'm more inclined to blame a connection somewhere along the thermocouple system, rather than the age of the thermocouple itself. Check every connection, especially where the wires connect to the mounting block.

I ran an absorption test of the new 630- 44 hour soak with a 2 hour boil in the middle, the best I could do with my schedule this week. Absorption came out to 1.2%, which is great. My kiln fires to a strong cone 6, probably closer to 6 1/2, but even at 6 it should be well within acceptable range. I don't fire to cone 5 and my baby kiln is out of commission right now so I can't do a cone 5 test for a couple more weeks. I gave some of the clay to one of my students yesterday and her initial reaction was the same as mine- it didn't feel at all like the old 630 and she didn't like it. However after throwing a couple of pieces she again had the same realization as me, which is that it still throws well, it's just different. I'm going to make a few pieces with it tonight and see if it's still as forgiving as the old formula. You could really abuse the old stuff without any problems- very little S-cracking and handles never pulled away.

So why did the breaker trip?