MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 Yes, I think that's basically it Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 (edited) Unwired the contactor, everything looks clean, no burn. Door relay also. Edited February 11, 2023 by MartinC Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 48 minutes ago, Bill Kielb said: Maybe a local kiln tech? Yes, I know one who lives close by. I think this may be it now Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted February 11, 2023 Report Share Posted February 11, 2023 (edited) Think I got the wiring slightly wrong so here's my updated version. Neutrals were in the wrong place and not all connected to L1 which was confusing me. Sedgefield Pottery is pretty close to Durham I think. Edited February 11, 2023 by High Bridge Pottery Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 3 minutes ago, High Bridge Pottery said: Think I got the wiring slightly wrong so here's my updated version. Neutrals were in the wrong place and not all connected to L1 which was confusing me. Sedgefield Pottery is pretty close to Durham I think. Yes, it's Bill from Sedgefield I know. He's actually retired and his assistant now runs the supplies side from Darlington. Bill still does repairs though. High Bridge Pottery 1 Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted February 11, 2023 Report Share Posted February 11, 2023 The door interlock is just a safety switch and not a relay. Just there so you can't send power to the kiln while the door is open. When it fails can you hear if the small click is coming from the controller or from the main relay/contactor. Whats confusing me is you say it can also fail when trying to start a firing and not hot. Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 (edited) For example. I set the kiln to come on Thursday night. The kiln didn't start (not the first time it has happened). I started it Friday morning and it started fine. It got to about 1000 and then stopped firing. The common failure is it gets hot then just stops. When it stopped firing when it got hot I could hear a quiet click. I have two controllers, both electronic so assume they don't have any moving parts to "click", and the fault was the same with both . It was not the heavy clunk of the contactor but something fainter. Perhaps it was the contactor making a different noise but I can't be sure. My wife was with the kiln on Friday and said she could hear any clicking. I looked inside the door switch (attached) and it looks fine. When I changed the contactor I got about 3-4 firings before the error started again. Honestly, I'm perplexed. (Having said that, I swore the quiet clicking was coming from the controller but that cannot be the case, surely?) Edited February 11, 2023 by MartinC Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 11, 2023 Report Share Posted February 11, 2023 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. Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 Following from the post above from High Bridge Pottery, the door key slots into this and turns the rotor, closing the contacts. I assumed, therefore, that this was then just a door safety switch. How does it work, if it is a relay? Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 What about this mystery box that is wired from the controller and to the contactor? Quote Link to comment Share on other sites More sharing options...
neilestrick Posted February 11, 2023 Report Share Posted February 11, 2023 1 minute ago, MartinC said: Following from the post above from High Bridge Pottery, the door key slots into this and turns the rotor, closing the contacts. I assumed, therefore, that this was then just a door safety switch. How does it work, if it is a relay? 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. Quote Link to comment Share on other sites More sharing options...
neilestrick Posted February 11, 2023 Report Share Posted February 11, 2023 1 minute ago, MartinC said: What about this mystery box that is wired from the controller and to the contactor? 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? Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 Here is the mystery box between controller and contactor. It's helpfully labelled relay so the problem could be in here. Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 Yes, it's wired from the controller plug and the thermocouple and outputs to the contactor Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 3 minutes ago, neilestrick said: 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? No keypad, external controller Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 11, 2023 Report Share Posted February 11, 2023 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. Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 5 minutes ago, Bill Kielb said: 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. The front is visible on the front of the kiln. It has a red light that comes on when the kiln is firing. It looks as though this box is what receives the signal from the controller and then transmits to the contactor to open/close. If the door switch is just that (for safety) then this could be the source of the problem. It will be old and although not drawing a lot of power, might be sensitive to the ambient heat of the kiln (or maybe even the cold when kiln won't start at night). It will need testing when the kiln fails Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted February 11, 2023 Report Share Posted February 11, 2023 If the safety switch was going bad the controller should be turning on and off I think. When you disconnect the interlock does it power down the controller? That black box looks a familiar shape to something I have seen before to control kilns, I can't remember how it worked though. I am guessing that's where the soft click is coming from which means it should be sending 240v to the contactor coil to close it and that isn't happening. Hard to know without being their when it fails. Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 11, 2023 Report Share Posted February 11, 2023 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. Quote Link to comment Share on other sites More sharing options...
MartinC Posted February 11, 2023 Author Report Share Posted February 11, 2023 44 minutes ago, High Bridge Pottery said: If the safety switch was going bad the controller should be turning on and off I think. When you disconnect the interlock does it power down the controller? That black box looks a familiar shape to something I have seen before to control kilns, I can't remember how it worked though. I am guessing that's where the soft click is coming from which means it should be sending 240v to the contactor coil to close it and that isn't happening. Hard to know without being their when it fails. Yes, the door switch is operating as needed. Opening the switch turns off the controller. Plus, it is a Stafford controller which restarts in case of a disruption to power so that isn't the problem as the controller is still on when the kiln fails. The black box looks like it might be bespoke to the kiln brand hence no part number for a third party supplier. Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted February 11, 2023 Report Share Posted February 11, 2023 15 minutes ago, MartinC said: Yes, the door switch is operating as needed. Opening the switch turns off the controller. Plus, it is a Stafford controller which restarts in case of a disruption to power so that isn't the problem as the controller is still on when the kiln fails. The only reason I brought it up was because I feel if the door interlock was faulty then the controller would also be having issues and as that is not happening I feel you can rule that out even with it being old. Bill Kielb 1 Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 11, 2023 Report Share Posted February 11, 2023 (edited) 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? Edited February 11, 2023 by Bill Kielb Quote Link to comment Share on other sites More sharing options...
neilestrick Posted February 11, 2023 Report Share Posted February 11, 2023 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? Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted February 11, 2023 Report Share Posted February 11, 2023 (edited) 1 hour ago, neilestrick said: 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? I would think the normally open yellow wire is the one going into the coil on the left and the brown is coming from the far left pole on the main bit. Not sure which blue is going there from the right side of the coil or where the red is coming from. I guess the black wires are going to a tungsten indicator bulb somewhere. It's a strange box as there doesn't seem to be a wire coming from the controller to that box to make it do anything. Maybe that plugs in another way. Thinking about it again the brown coming from the main contactor makes no sense as then the power would only flow when the coil is on. Edited February 11, 2023 by High Bridge Pottery Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 11, 2023 Report Share Posted February 11, 2023 (edited) 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. Edited February 11, 2023 by Bill Kielb neilestrick 1 Quote Link to comment Share on other sites More sharing options...
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