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MFP

Bottom ring not reaching temperature

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I have an Olympic 1827H electric kiln.  The bottom ring was hardly reaching cone 4. Since it is an old kiln, I thought the elements were the problem and replaced them. Fired again. Still cone 4 in the bottom ring. Olympic thinks it is a switch problem and is sending a new one. But I have seen references on here to relays. So I was wondering if you could please tell me more about relays and how to determine if they are functioning properly?  Apparently there is also some kind of coil.  The elements are heating up but just appear to not be getting enough juice. Middle and top rings are achieving hard cone 6, 

Thanks!

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38 minutes ago, MFP said:

I have an Olympic 1827H electric kiln.  The bottom ring was hardly reaching cone 4. Since it is an old kiln, I thought the elements were the problem and replaced them. Fired again. Still cone 4 in the bottom ring. Olympic thinks it is a switch problem and is sending a new one. But I have seen references on here to relays. So I was wondering if you could please tell me more about relays and how to determine if they are functioning properly?  Apparently there is also some kind of coil.  The elements are heating up but just appear to not be getting enough juice. Middle and top rings are achieving hard cone 6, 

Thanks!

If it has switches, chances are it does not have relays.  Relays are used in automatic (ala cress et al) and in computer controlled (ala Bartlett et al) kilns.  Manual kilns, timer kilns and kilns with kiln sitters do not require relays to work.

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@MFP Is this a digital kiln or manual?  If it's manual, you probably don't have relays. If it's digital, you probably don't have switches. If you do have relays, they generally either work or don't. 

If your elements are all in good condition and everything is working properly but the bottom is running cold, try changing how you load the kiln. Load the bottom less densely- tall vases, large bowls, etc. Save small pieces packed together for the middle of the kiln.

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Thank you so much Neil. I had thought I was packing it too tight with too short shelves. I took off the cover yesterday to attempt to replace the switch....and voila!  The top wire to the element popped right out....it had not been crimped tightly. So that might have also contributed . It is an old Olympic with knobs. I couldn't not get the knob off and then had to get the switch lined up with the knob again so it displayed the right place on the dial. So the switch was not replaced.  I did do a bisque prior to this where I left the bottom more open....and when it reached red heat, the color was uniform in all three ports.  Also....plug peep holes or leave them open? I was wondering if I was starving the bottom of O2 by putting in the peep. 

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Thanks Liam....there's nothing in that section except wires an way....once I got it open it was pretty straightforward. The top element wire popped right out when I opened the box.....that and how I was loading it might account for the problem.  I have a new switch but couldn't figure out how to get the darn knob off.  All the  electric guts must be in the center section.  It does have a coil but since the other two sections are reaching hard 6 that isn't the problem. I have learned to cover the last part of the load with a shelf....then I don't have any heat loss through the lid.  I also turn the top and bottom on high and leave the center on 6. That has worked really well....at least in terms of the top. 

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Typical knobby switch is retained by a nut that's behind the knob, hence that knob has to come off - which you a'ready know, no doubt!

The shaft typically has a flat (although some are splined), and knob just presses on - some have a flat retention spring, or aforementioned set screw.

Any road, a few taps/bangs might help, also a touch of heat (be careful!); if possible to get a drop  of liquid wrench in the right spot, that might help as well.

Given you have new switch in hand, removing the old knob might involve destroying it, which may not be too bad, just limit the destruction to the item to be replaced ...cut carefully!

 

aa knob.jpg

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Thank you, Hulk and Neil. The switch I received is white and the shaft does have a retention spring thing. I will try WD40 and see what results I get with that. I got it just loose enough with a slight pry that I wound up getting it off the calibration and had to make sure everything was lined up correctly again.....and put a piece of sponge behind the switch to keep it from twirling..  And yes, I spied the retention screw behind the knob....undoubtedly somewhere there is a special skinny wrench for unscrewing it.....hence the lock spring on the knob. I want to see how it fires now that the top wire is securely crimped. I will let you know what happens!  My knob is one of the silver ones with  Lo, 1 to 6 and High. 

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Neil...do you know anything about the big Olympic gas kilns?  Sarah Perez is always after me to get my huge gas kiln operating....but said that my burners might need to be "braised and redrilled".   I have no blasted idea what that means. The kiln has never been fired. I did anticipate lots of quality time with the burners and WD40 to get the ports open.  The burners I had before were home made. I don't know anything about manufactured burners.  These burners were from the original company whose factory burned down.

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5 hours ago, MFP said:

Neil...do you know anything about the big Olympic gas kilns?  Sarah Perez is always after me to get my huge gas kiln operating....but said that my burners might need to be "braised and redrilled".   I have no blasted idea what that means. The kiln has never been fired. I did anticipate lots of quality time with the burners and WD40 to get the ports open.  The burners I had before were home made. I don't know anything about manufactured burners.  These burners were from the original company whose factory burned down.

Start a new thread and post some pics of the burners and control system. @Bill Kielb will be more helpful than me if they're venturi burners.

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Replaced the switch and the problem persisted. Fixed it by gluing one inch of refractory blanket to the outside of the kiln bottom. I also have a firing schedule where the bottom is always turned up more than the middle. I also put a final shelf between the last pots and the lid. I end with the bottom of. High, the middle on 5.5 and the top on 6. Cone 6 everywhere now!

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