Bill Kielb

Just a note here, really nice cleanup job! Oh, the note, the yellow wire looks like the insulation is trapped under the screw. I would double check this to make sure it is a good metal to metal connection. If it is an Fth error now, I still think you will need a test run to 500c or so to make sure all elements are working. From there if it is one set, then you probably can look at relays. The elements really look good. Who knows, you may find similar corrosion on the relay connections as well.

No worries, it can be a relay to one of the element groups. Easy to fix. The elements look to be in nice shape.

Since you have a new thermocouple and it’s now in good order can you run a single segment test as above and see which elements glow and which do not?

Suggest: Just count the number of complete coils in the entire length, measure the length. This can be done on several just to confirm they are the same or not. Euclid can then distribute evenly once a wire size and resistance value is picked.

Interesting Eth is electronics too hot, Fth is failed to heat. Your manual https://www2.ceramics.nidec-shimpo.com/wp-content/uploads/2019/06/Orton-Autofire-Manual.pdf. Eth means the circuit board is getting too hot, so why is it overheating. Maybe post a picture of your thermocouple issue it’s hard to interpret the description. Assuming the control is in a reasonably cool location and the circuit board is not overheating, I think I would write a single segment program to 1000 degrees f (537c) and see which elements heat and which don’t.

Hmm, hope you return to answer questions but if you have central AC, then you will just change that breaker size as appropriate to service the heat pump. Twin or tandem breakers are an option but not for your kiln you will use it to free up open adjacent locations for the heat pump. A lot has been said about their use and this is likely a good option. Just to add a bit on tandem breakers and panels, old panels take older style tandem breakers or “universal” and the panels are generally marked by the manufacture with the permissible number of openings that can be added this way. The model # will often be something like: “XXX 30/40 XXX” which generally means 30 openings, 40 are the max. New panels that are marked “CTL” take compatible tandem breakers ONLY in locations of the panel that allow this breaker. Generally you can’t use a universal tandem for CTL panels. A good electrician is nearly a must so this gets done right. Your kiln cannot be on a tandem breaker in any way, it is considered a continuous load and will excessively heat the double breaker. Some suggestions / tidbits - when they size your heat pump, make them do an accurate manual J load analysis on your home and give it to you as proof of sizing. (A blower door analysis is a plus to determine infiltration if they can do it) Additionally your climate is a bit milder than I am used to, but cold climate performance heat pumps guarantee their rated output down to -5 or lower. It’s nice to have that performance available when needed and it appears you can have occasional overnight occurrences of this. In general they make heat about 300% - 400% (COP ~3-4) more efficiently than plain old resistance heaters at your typical outdoor air temperatures. The outdoor units do condense and defrost, so placing them where the water can drain away from sidewalks etc… important to not have any icing issue with foot traffic.

I might be able to help here - been converting City of Chicago homes for a bit now and recently attended a meeting to discuss your area. Just a question or two, what size is your service in amperage ( main breaker size), how many positions are in the panel, do you have central AC, do you have an electric stove and do you have an electric water heater and do you have an electric dryer.

interesting in the end Stull seems to have reasonably simplified all this to regions in his map and a matte / gloss line based on si:Al

Hmm, tell me that the new contactor is set up so power comes into the contacts marked L1,L2,L3 and the ELEMENTS are fed from the terminals T1,T2, T3.

There are several relays, including two solid state timers. You will need to locate where the hum is coming from. Does this kiln have a three position low, manual, high rocker switch?

If it is an intermittent high limit, you can jump the yellow and red for a supervised firing test. The thermocouple to that thing appears to be pretty small gauge as if it is only for use by that safety. ….. if it is a safety. Can you see where that thermocouple terminates? What temperature is it sensing?

I would submit, it’s powered (brown and blue) it has its own relay (nc, com, no), it has a pilot light that stays on and it’s thermally dependent but not adjustable. My total guess because of the non adjustable part, a fixed high limit.

Is that the controller or perhaps a high limit? Just curious what is on the front of that. It is powered and has its own internal relay.

Good catch! I thought his looked like 8 in the picture. Unfortunately 14 gauge has a lower lifespan, but if that is what fits. I have bent #8’s - no issue, just need a decent tool. I want to say the only #14’s I have found in a kiln was in someone’s alpine inside the protection tubes, twisted tip as well. Not good for longevity! Might have been a Geil that was reworked. For cone ten I would definitely try and use 8 gauge and if a complicated bend is needed a propane torch and decent needle nose pliers certainly make it easy to shape the 8 gauge wire neatly any way you might need. Looks like a standard protection tube with a spacer installed- just rechecking the picture.

I’ll be darned, nice relay! I see it’s rotary so one can always check if it is cycling by watching the rotation of the shaft. It can also be cycled manually from above with the right hex socket or needle nose players. The contacts look great, we don’t know what the drive coil looks like though. If this is a pilot relay it operates the large relay. One other thing to consider is your control likely has its own onboard relay that would drive this. Any and all those relays if intermittent likely would be affected by heat. If this is truly the pilot that drives the large relay, manually setting this to on briefly after the kiln stops cycling will narrow down the culprit a bit.

Hmm, my best guess here. It looks like element loads are split among the three contacts so prox 8.6 amps each. Depending on the rating which seems based on switching and derated at ambient operating temperature (60c), these contacts might be rated only at 9amps (switching prox. 300-600 times per hour) So the simple question would be if these contacts degrade rapidly, this relay is underrated and causing issues. The inrush from elements should be mild as compared with an ordinary tungsten lamp which is often briefly in excess of 8X, so this could work even at 60c - which is not that hot but seems underrated in and around kilns. It should be easy to inspect, if worn or burned with little use, you need a better rated relay, without the auxiliary contacts. Not sure why they are here anyway. If the other relay in the picture is the pilot for this, it could be damaged and likely will suffer a significant inrush to fire this relay. So simple to check relay contacts and understand what has failed or which contacts have burned excessively and replace as necessary. These are enclosed so not necessarily free air. 60c is not hot for kiln service, my thought is this is likely under rated. The pilot relay however will experience a reasonable amount of wear as well, even though only switching this contactor. It won’t last forever. Definitely check both for contact wear, obvious material transfer etc…. You should measure virtually zero resistance across any of the relay contacts when closed or if live definitely less than a 0.1 volt across them. Live stuff is live though and carries the danger of electrocution. Maybe a local kiln tech?

IMO, switching the neutral provides for the possibility of a higher resistance connection, something beyond zero volts. Most things are surrounded or in proximity to a ground plane of sorts so switching to me adds more risk. The specs are confusing to me, but why he has a three pole relay with an end switch is a bit of a mystery. If he has more than one set of elements, then that relay may be applicable. My assumption is those contacts don’t exceed 25 amps total load though. A few pictures of the wiring to the relay with context included for the connections would likely solve the mystery.

Yep, Stull! He was limited by available fluxes and his claybody at cone 11. The most useful for me is his matte / gloss line and with some indication of how it ought to fire which then prompts further diagnosis such as is this fully melted, etc…. We get the question of how to make a matte glaze here every so often. Slow cooling, magnesium matte are the typical responses and they are fine, but moving something between matte and gloss generally follows Stulls trend which is fairly easy. I have designed visually as well and Stull folks often group. I do like the simple true matte definition though and have observed the over fired runny matte as well as added silica from matte to full gloss. Sue M has some nice in studio testing and research detailing how to get better clarity etc…. Derek Au (Glazy) I believe is trying to gather data for a heat map to apply to the Stull chart. I am partial to Flux ratio as being an initial indicator if a glaze likely can be durable. The Katz research on boron required I find very useful as well. Cullen W Parmelee also interesting work - (Stull Era), lots more for sure not to be forgotten.

Looks like this is rated at 25 amps max and your load is 26 amps and each is rated at 9 amps @ 240 v.. This is also a three phase contactor with an end switch. You service should be single phase 240v, 1 hot wire and one neutral. Not sure this is the right relay for several reasons. Even though resistive circuits start without tremendous inrush, they do generate a lot of heating in the circuit though. It’s regular practice in North America to supply them with wiring and switching that is rated 125% though to minimize the effect of the heating on the switching device such as a circuit breaker. As a control relay, these contacts should be rated well beyond the maximum load for longevity. Since you have single phase 240v (not split phase like in North America) you really only need to switch the hot phase. Picture of how the elements hook to this would help, and the auxiliary contact is rated much less so depending how it’s used, could be an issue as well.

Yes lots of generalities around clay often don’t always hold up in all cases but being extra careful not a bad thing I suppose. Stull drew his map and did his research prox.. 1912 so maybe he indirectly inspired Currie. RT Stull was the head of the ceramics engineering department at the University of Illinois - my home state.

Nice picture(s). 8 gauge type K I believe. If you buy it 6” long then trim leads from the back to match the existing size. The good news is that the weld at the tip appears to be failing which definitely could cause erratic operation. Usually it corrodes away and is very visible see below. Yours looks like the weld is defective. To make a thermocouple the two dissimilar wires need to be reliably connected to each other. Your weld looks cold and twisted so may be intermittent. Still check all connections visibly and with a screw driver - the yellow thermocouple wire. Make sure the bare wire is actually under the screw and it is reasonably tightened FYI - After many firings, when we see the wear bellow we just replace them beforehand knowing they only have a few firings left on them. Picture of a new thermocouple below for reference

You may find this a good watch. https://youtu.be/DptgFBkynHA Sue is one of my favorites and recreated Stull and presented at 2018 NCECA. Her presentation was to simulate Stull in test tile form. To answer your question Si:Al ratio of 4.34:1 ends up to be relative as that glaze needed additional boron to ensure it would melt over heavy underglaze applications which was the specific issue we were trying to solve the summer of 2017. The additional boron does affect the surface. However, that glaze was designed as a true matte, meaning even over-fired it will be a runny matte. Anyway, no method is foolproof but if you use Stull as a reasonable guide to the expected surface it can become a game changer. Predictable surfaces often lead one to inquire and test whether things are under fired for the composition. Anyway, Stull kept his fluxes at 0.3:0.7 for good reason at the time, and fired and mapped the result. Sue emulated that in tiles as Stull becomes another tool in analyzing glazes. Sue does a great job of explaining it IMO and is worth the watch and read. Additionally there have been studies on mattes and durability and there certainly are many true mattes that are durable, so testing IMO is always wise. Funny, everyone wants to slow cool to get the matte look but a matte that develops later is ok and durable? I am not sure why that would be better but believe testing is always wise. Anyway, Stull can be helpful in my view and SI:Al has a pronounced effect on the final expected surface texture. Like anything though, just another tool, have not found the one stop analysis tool, limit formula, experience, etc…. Yet. It is interesting you sort of re-created Stull on your own. Sue has a wonderful site IMO and generally shares her research. Worth the read in my opinion. Her site: https://suemcleodceramics.com/understanding-cone-6-nceca-presentation-2018/

Type K are typical, post a picture of your thermocouple and the information on your equipment tag of the kiln. (Model, voltage, cone, etc…) to be sure. Thermocouples act like a battery and output a very tiny voltage proportional to their temperature so while it does happen, jumping from one reading to another may indicate a loose connection, contact with the metal shell of the kiln as things expand, etc…. The more pictures here (off the thermocouple and connections) the more informed the answers will be.

As you have experienced, there is a wide definition of matte surfaces often qualified as satin or semi matte etc…. Transparency varies as well, so some level of right up until it’s translucent. I think all perspectives are valid though. I have bowls matte on the outside for their aesthetic appeal. Some have gloss liners, some have satin finishes inside. The ones with zircopax often metal mark regardless of the finish. I think testing is the only way to find out if it’s appealing and acceptable and functional to you. I think my point about the recipe is it most likely can be done to fulfill your needs. The recipe I posted is simply one we created when we had similar needs. The real reason for my post is the glaze listed above appears to be is a lowfire or cone 05/04 style glaze. Since you are firing cone 6 it presents a bit of a problem or extra step to getting your clay fully vitrified and in the end may not fit.

It is true about the lids, for a few months for various odd reasons I lost lids to the pots I made. The rest of the topless accounting was a light hearted joke created by members in the studio surmising what could be done with the bottoms. It grew into the topless pottery marketing approach. Just a little fun.