Older PSH/Euclid automatic kiln - FtH error

[laurasaurus]

I have popped open the kiln again to look at the relays and grab the part number.  Just to double check these two are the relays right? Unfortunately the plastic melted to the screw and became brittle over time and snapped off the bottom screw but I can still reattach the top. 

[laurasaurus]

6 hours ago, neilestrick said:

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.

Do you think EtH is still an issue after I cleaned the board? I was hoping it was taken care of and that I only had to deal with the FtH.

I will monitor the controller again tonight when I try it again to check my elements and relays. I really don't want to replace the controller as they are like $500 CDN.

[neilestrick]

13 minutes ago, laurasaurus said:

Do you think EtH is still an issue after I cleaned the board? I was hoping it was taken care of and that I only had to deal with the FtH.

I will monitor the controller again tonight when I try it again to check my elements and relays. I really don't want to replace the controller as they are like $500 CDN.

EtH shouldn't have been an issue in the first place, so hard to say if it's going to be an issue again. Perhaps cleaning the board solved it. Still need to figure out why it's shutting down and restarting, though. Did you check the fuse holder?

You may or may not be able to find those relays if they're really old. Post the part number or a pic of the relay label.

[laurasaurus]

Here you are, I am in contact too with PSH/Euclid. Fingers crossed.

I gave everything a good wiggle and inspection but could you let me know where I should be looking for the fuse holder?  I added a photo.

Thank you for all your help!!!!

[neilestrick]

Those relays still exist: Zoro. Just Google the part number and you'll find them in several places.

What's the black box in the bottom of the panel?

[laurasaurus]

Looked like main power cables going in there. I checked it out and everything was okay.

I also opened up the controller just now and some parts were loose so I pushed them back in, hopefully that is why the controller glitched!

 

[laurasaurus]

The kiln is at 875F now and I just see the top and bottom elements on, the whole middle appears to be out.

I did notice that it's taken ages to get up to this temperature, about two hours. Also when starting out in the 100s the relays would click very quickly but more far apart, it also was ridiculously slow today move up a degree but it sorted itself out as it got hotter. 

Good news though, the controller didn't do anything off this time around. It just have been the loose connection on the circuit board.

[laurasaurus]

I managed to snap a photo of the insides.

[Bill Kielb]

8 hours ago, laurasaurus said:

Here you are, I am in contact too with PSH/Euclid. Fingers crossed.

 

Hmm, as expected one of the two relays out. Great relays, I used them for years and widely available …. Except they need to be 12vdc which when googled often come up with 24, 120v ….. always been that way so careful that they end in 12 vdc before you order. Here are some links to verified sources, Amazon was lowest for me but when first searched displays a relay with the wrong voltage. Neil’s is good above as well. For $13.00 I would change them both.
Eventually I would like to see a picture of the orange thing with two leads coming out of it that goes across the relay. It’s known as a snubber, super good to have, super uncommon for kilns. I just want to verify what it is so maybe the part number on the front of it at some point.

https://www.amazon.com/Omron-G7L-2A-TUB-J-CB-DC12-Insulation-QuickConnect-Terminal/dp/B005T73UYC/ref=sr_1_1?crid=6S6OXWTXPIBM&keywords=G7L-2A-TUB-CB-12v&qid=1676368818&s=industrial&sprefix=g7l-2a-tub-cb-12v%2Cindustrial%2C87&sr=1-1

https://www.newark.com/omron-electronic-components/g7l-2a-tub-j-cb-dc12/relay-dpst-no-277vac-25a/dp/36K7474
 

https://www.grainger.com/product/OMRON-Enclosed-Power-Relay-6-Pins-1YCZ3?opr=PDPRRDSP&analytics=dsrrItems_1YCZ1

My quick thought about Eth would be if you laid the controller down on top of the kiln while firing during the trial period or it was close enough to get heated by the kiln at some point.

There is a test button on the side of those relays, you could run a piece of tape across one at a time depressing it and run a test to see which relay is the culprit. They are wired to activate together so if you are looking at this while operating one of the two black push buttons will likely be pulled inward and the defective one, very likely not. Please be careful if working around powered circuits!

Edited February 14, 2023 by Bill Kielb

[High Bridge Pottery]

The camera does seem to be picking up a slight glow from the middle and center elements, especially in the third groove up from the bottom.

[Bill Kielb]

4 minutes ago, High Bridge Pottery said:

The camera does seem to be picking up a slight glow from the middle and center elements, especially in the third groove up from the bottom.

I would be 99.99% sure both elements are out from that test and picture and this kiln has two relays with top and bottom on one relay and middle two elements on the second relay

[High Bridge Pottery]

17 minutes ago, Bill Kielb said:

Eventually I would like to see a picture of the orange thing with two leads coming out of it that goes across the relay. It’s known as a snubber, super good to have, super uncommon for kilns. I just want to verify what it is so maybe the part number on the front of it at some point.

Does that work similar to having a diode across the coil contacts to stop it dumping electricity the wrong way when the magnetic field collapses or is it a different idea? 

 

6 minutes ago, Bill Kielb said:

I would be 99.99% sure both elements are out from that test and picture and this kiln has two relays with top and bottom on one relay and middle two elements on the second relay

As far as I can tell there's 6 elements in the kiln with one relay doing top and bottom and the other doing the two middle and two center.

[Bill Kielb]

17 minutes ago, High Bridge Pottery said:

oes that work similar to having a diode across the coil contacts to stop it dumping electricity the wrong way when the magnetic field collapses or is it a different idea? 

 

It does, not sure that is the shape of a diode though so want to double check. She has a remote controller and these power relays are a decent inductive load and take very little current to activate (I used to use them) so protecting the relay in her remote controller a really good thing. Just want to verify how they are doing it, hopefully it’s a diode to which it’s permanently crimped in the circuit so polarity likely not an issue as long as the wires go back. Just double checking, not something often found in kilns.

Edit

And yes, my interpretation is top and bottom on one relay, middle on another so really likely one whole relay out.

Edited February 14, 2023 by Bill Kielb

[Bill Kielb]

8 hours ago, laurasaurus said:

Looked like main power cables going in there. I checked it out and everything was okay.

I also opened up the controller just now and some parts were loose so I pushed them back in, hopefully that is why the controller glitched!

In the very end, after this is all working, let’s take a look at the old power leads that came with the kiln. The blue wire in your picture which would be used in EU wiring typically appears to be aluminum. If the old power leads are aluminum  (as was common for a time some years back) I would suggest changing to copper eventually. If it’s just plated wire, then likely ok. Something, maybe to plan for inthe near future if in fact aluminum.

[neilestrick]

What firing program are you using to test it? Rate of 9999?

There are 6 elements. Since the middle 4 are all running on one relay, then they're not pulling much power and may actually be running as intended. They'll take forever to glow, and even then may only glow lightly. Do a paper test to see if they're heating or not. I'd go ahead and replace the relays regardless, as it's a cheap fix.

It could be that the loose connections on the control board were cause a relay to fire improperly, and/or the power supply was sketchy.

[laurasaurus]

I woke up to so much information this morning, thank you all for your help!  I am learning so much. I knew with owning a kiln, especially an older one, I would have to do some maintenance but I had no idea it was going to be right from the start!

Relays purchased, thank you all for sharing links, I ordered from Newark because they have a Canadian equivalent.

I couldn't figure out the 9999 rate so I just selected a fast fire option and waited. I didn't see anything in the manual about a 9999 rate but perhaps I was too flustered and missed it. The previous owner did the paper test before she sold it to me but it doesn't hurt to do it again. I will do that this week.

As for the orange snubbers, I can take a photo with the part number when I change out the relays but have attached one I took last night. As well, what is the yellow box below? 

For the blue wire, do you mean the thick one at the bottom? If so, it definitely looks aluminum.  What would be the benefit to changing it over to copper?

[High Bridge Pottery]

The yellow box is a transformer, it will take the 240v from the wall and convert it to a lower voltage. Looks like 24v judging by the sticker.

[neilestrick]

The controller runs on 24V, so the transformer drops the voltage for it. The transformers is powered at 24 volts AC, but the outputs to the relays are 12 volts DC.

[Bill Kielb]

1 hour ago, laurasaurus said:

For the blue wire, do you mean the thick one at the bottom? If so, it definitely looks aluminum.  What would be the benefit to changing it over to copper?

Yes I do mean that blue wire, but it is for later. If the feeds are aluminum as the blue one appears, it will be something prudent to change in time. Aluminum for kiln feeds is just not good practice anymore. Not something for today, maybe something for the near future if they turn out to match the neutral and are aluminum also.

[neilestrick]

1 hour ago, laurasaurus said:

I couldn't figure out the 9999 rate so I just selected a fast fire option and waited.

On a fast fire setting, it makes sense that it would take two hours to to get to 875F, because it's not firing at full speed but rather somewhere in the 500F/hr range, which it may not be able to keep up with.

[Bill Kielb]

2 hours ago, laurasaurus said:

Relays purchased, thank you all for sharing links, I ordered from Newark because they have a Canadian equivalent.

I couldn't figure out the 9999 rate so I just selected a fast fire option and waited. I

I don’t think there is much risk here, your relays are parallel wired to activate and the connections look good so both relays fire together. You waited until 800 degrees so I would expect anything not glowing is just not operating.

You can test each relay by pushing and holding the test button in. Unfortunately doing this with power applied can be tricky. Instead you can tape over the push button manually engaging it and observe the operation.

The problem with doing this is your elements will immediately turn on and stay on without the controller calling for the machine to run. So turn off power to the machine, tape the relay test switch down firmly and then energize the kiln staying away from any open wiring. The elements will begin to glow for the relay that has the test button depressed. In this way you can test which relay goes to which elements. It’s not 100% foolproof but fairly close unless there are burned contacts inside the relay. 

Nothing on the back of those relays indicates the contacts have overheated so at this point it appears to be a relay coil that is not working.

Hard to address all possibilities remotely but the logic thus far, indicates you likely have a bad relay.

Edited February 14, 2023 by Bill Kielb

[neilestrick]

3 hours ago, Bill Kielb said:

You waited until 800 degrees so I would expect anything not glowing is just not operating.

I've worked on lots of kilns where the middle elements don't glow much, and because the kiln wasn't on 100% during the test, that would make them even less likely to glow. If you look at the photo you can see that they're starting to glow, especially at the second element up from the bottom. However it could still be a sticky relay that's the problem.

[High Bridge Pottery]

That one did look a bit suspect to me because it has a hot bit and a cold bit. Compared to the rest it seem odd.

[Bill Kielb]

1 hour ago, neilestrick said:

I've worked on lots of kilns where the middle elements don't glow much, and because the kiln wasn't on 100% during the test, that would make them even less likely to glow.

Maybe, a kiln that doesn’t climb, center elements that are dark, relays tied together to operate in parallel. The test button is an easy test option as well as amperage tests and voltage confirmations…... Seems to be a reasonable probability it is a relay. Other things definitely can occur on occasion though. For the thirteen  - twenty bucks or so for a relay, I think it’s the most reasonable choice actually.

[laurasaurus]

In the end when I left the kiln yesterday it  was at 970F and the elements looked the same.

I can check the amps for each element with a multimeter tomorrow but since the relays were clicking a little erratically I will change them both out, they aren't too expensive to replace.  I do need to get an idea from PSH/Euclid on what the amps should be for the elements though. 

I will also do the paper test again tomorrow as well.