Can you Leave while the Kiln (w/Controller) is ON? - WarmGlass.com

Can you Leave while the Kiln (w/Controller) is ON?

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candala
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Can you Leave while the Kiln (w/Controller) is ON?

Postby candala » Sun Jun 08, 2003 1:31 pm

I'd like to hear everyone's opinions. Do you leave your house (shopping, errands, etc., or studio for that matter) while your kiln with programmed controller is running?

I just got a 14 inch Jen Ken (from Marty - Centre DeVerre - YAY! HE'S GREAT!) and it has a Bartlett 3 key controller. I've heard and read that you are NOT supposed to leave the house just in case a relay breaks and this can cause a fire, etc.

What do you all do, stick around until the kiln shuts off? Also, if there is an emergency and you HAVE TO leave, do you just hit the power switch? Thanks for your opinion.

Cindy next door
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Postby Cindy next door » Sun Jun 08, 2003 1:43 pm

I try to be home AND awake when reaching fusing temps. If not, I tell Jackie to keep an eye out for smoke. I do leave and sleep when beginning the ramp up and ramping down.

I have had my kiln get stuck at a segment often enough, but not where it just continues to go up, like some have had.
Cindy next door

Cynthia

Postby Cynthia » Sun Jun 08, 2003 2:11 pm

The best advice is to always be present.

That being said :shock: I will start a firing and plan my day for leaving the studio to occur during non-critical stages unless I know my program...then I just make sure I'm there to turn the kiln off before ending my day. I probably shouldn't work this way, but my studio is in the house and my kilns are in the garage (detached), so once the kilns are up and running, I am back in the studio and not with the kilns. I will fire overnight too if I am running a schedule I don't need to change on the fly. I figure that if they screw up and I burn anything down it will be my outbuilding and a car. That's probably a false sense of security.

My mother used to tell me, "Don't do as I do, do as I say!" I don't set a good example, but I'll espouse one :wink: .

Kitty
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Postby Kitty » Sun Jun 08, 2003 3:07 pm

i don't leave the house when they're running, but sometimes (rarely) i go to bed when the big kiln is ramping down. i seem to remain semi-conscious when i do that, and hear the controller clicking. in general, i am awake for the whole schedule. nights when i don't sleep in my house i unplug the kilns, even if they're off. maybe that's silly, but there you have it. kitty.

Valerie
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Postby Valerie » Sun Jun 08, 2003 6:15 pm

I must be walking on the wild side :shock: I set my kiln with the delay timer and go to bed for the intial 2oodph ramp up, I give myself an hour or so leeway before final destination ~lol~ maybe I should increase my fire insurance :idea: I have an Orton 12 key. Knock on wood, I have never had a relay stick. I'll leave myself open for a thousand I told you so's

Paul Tarlow
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Postby Paul Tarlow » Sun Jun 08, 2003 6:38 pm

On serveral occasions I've read where people won't leave their kiln on its own on the way to full fuse -- but will leave it alone on the ramp down.

Since the controller cycles juice on and off in both directions and since the fear is that it will get stuck in the on position -- isn't the risk the same throughout the whole program?

- Paul

Rob Morey
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Postby Rob Morey » Sun Jun 08, 2003 7:34 pm

I only fire during the day, but I often leave to run errands and such. I try not be gone for more than a couple of hours at a time. That way, if the controller goes out, I will be able to shut everything down before any major damage. I used to fight fire in a small volunteer fire department outside of the San Francisco area and I've seen some wild stuff. Once we went to a garage fire and the whole garage was involved while the family was in the living room watching T.V. without a clue that anything was wrong. Buy the time we got them out the kitchen and a bedroom were destroyed. It can happen fast so I'm leery about leaving it overnight.
I've been experimenting with opening my kilns at fusing temps and manipulating the glass so I want to be home and awake at that time anyway. My kilns are in my garage and very seldom do I bring my car in if the kiln is above 300 degrees. I had a gas tank go bad on a car once and I woke up the next morning with a giant puddle of gas in my garage. I'm afraid if that happened with a kiln running they might be picking up parts of me all over the place.

Rob

Brian and Jenny Blanthorn
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Re: Can you Leave while the Kiln (w/Controller) is ON?

Postby Brian and Jenny Blanthorn » Mon Jun 09, 2003 4:13 am

candala wrote:I'd like to hear everyone's opinions. Do you leave your house (shopping, errands, etc., or studio for that matter) while your kiln with programmed controller is running?

I just got a 14 inch Jen Ken (from Marty - Centre DeVerre - YAY! HE'S GREAT!) and it has a Bartlett 3 key controller. I've heard and read that you are NOT supposed to leave the house just in case a relay breaks and this can cause a fire, etc.

What do you all do, stick around until the kiln shuts off? Also, if there is an emergency and you HAVE TO leave, do you just hit the power switch? Thanks for your opinion.


First time run a fast cycle n sit with it

Make shure it acctually works

It is not uncommon 2 have it wired up so it does not cut off

My cycles R about 3 days

I never leave it more than a few hours

I have it set if I do forget it it will come down

Also got a heat fuze

I have been known 2 sleep with the kiln on

:sheep:
Image

Peg
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Postby Peg » Mon Jun 09, 2003 8:26 am

It has never occurred to me to stick around when firing. I have a front loading Firecracker from Kilncare with an ST501 controller http://www.kilncare.co.uk.
I turn it on and then go out for the day, or if at night go to bed quite happily.
My insurers haven't put any excess on my policy, though they know I have a kiln in the basement - Maybe kilns and controllers in the UK are safer than in the US? They are certainly more expensive.

Marty
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Postby Marty » Mon Jun 09, 2003 8:57 am

I've got Digitry controllers for mine; start-n-go (tm).

Phil Hoppes
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Risk...

Postby Phil Hoppes » Mon Jun 09, 2003 10:02 am

To Paul's comment, he is correct. People are under a false sense of security if you think that a relay will only stick on the way up vs the way down. The way the circuit works you have a small relay, SSR or mechanical, that triggers the coil in a larger relay, again SSR, mechanical or mercury. There is no "directionality" to any of these devices. In other words, there is no sense of going up or going down, just on and off. A failure can occur when your kiln is going in either direction. SSR (Solid State Relay's) and mechanical relays will fail in the ON position. A mercury relay will fail in the OFF position. For this reason mercury relay's are preferred for switching the main current to your elements. Note, however, that this does NOT mean you cannot get a run away kiln if you use mercury relay's. As I mentioned, there is a relay before the main relay that controls it's status, and if this relay fails on, even a mercury controlled kiln will run away.

When I've looked into the design of most if not all controllers this is really a pet peve of mine. The electronics to put in a secondary, redundant backup shut-off are not that expensive and the consequences are potentially so sever I find it inexcuseable that kiln manufacturers do not include this at a minimum as an option. The probablility of a single relay failure is not that small, the complaints on this board are testimony to that. The probability of two relays failing at the same time however is quite low and could make a significant contribution toward safer kiln design.

For myself, I'm in the process of building my own kiln. I took Larry Fiedler's class, which I highly recommend, and from that class there are a number of options available to you in securing your kiln from runaway events. The easiest is to get yourself a kilnsitter from an old ceramic kiln and wire that in series with your main relay control. Put in a cone at a temp that will be higher than most of your firings but low enough that if it ran away it will kill the kiln before things get too hot. A second option is to get a setpoint controller. Omega makes and sells these types of controllers. You would do the same thing as the kilnsitter and wire it in series with your main relay control. A setpoint controller will require a second thermocouple from your kiln. Again you would set the setpoint controller to a higher temp than your normal firings. A few advantages of a setpoint controller is that you can adjust your max kill temp easier than you can with a kilnsitter (assuming you don't have a ready supply of different firing cones on hand). A second advantage is that a setpoint controller can be used to control your kiln should your main computer fail. If you put a range controller in series with the setpoint controller you can control the rate at which you fire and the maximum temp that you intend to fire to. For me, I plan on using at least the setpoint controller as a backup. Since the kiln I'm building is a bell kiln, I'm not sure that a kilnsitter will work as I suspect given the mechanical nature of how they are designed and function would make them sensitive to vibration. It would have to mounted in the bell portion of my kiln and the hoist mechanism that will raise and lower my bell should be fairly smooth but not vibration free and I fear I would probably be dorking around trying to reinsert the cone all the time. Given the cost of this kiln that I am building however I am strongly considering putting in a dual setpoint controller system. I haven't costed it completely but from Larry's class I think the setpoint controllers are a little over $100 plus the thermocouple. The total kiln cost is going to be in the neighborhood of 4K so for less than 10% of the cost of the kiln I can put in a double redundant failsafe mechanism to ensure I don't get runaway of this kiln. That is cheap insurance in my book. I'm also going to install a setpoint controller on my 24" Paragon as that kiln is large enough that it could do some damage if it ran away. (Which these have definitely done...just ask Avery and Brock. There were two of these which went nuts on them at Vitrium studios last fall. Not a pretty picture.)

Hope this helps.

Phil

Lauri Levanto
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Postby Lauri Levanto » Tue Jun 10, 2003 3:21 am

In my bell kiln I have two circuits behind one controller.
The side and top elements have separate relays.

If one fails ON, then the controller will shut the other
when the temp rises. Either element can reach no more
than 700 C alone.

I would like to add a gold wire fuse, too. At the moment
I can't afford it. It works like a kiln sitter. at a certain
temperature the gold wire melts and breaks the circuit.

-lauri

Lynne Chappell
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Postby Lynne Chappell » Wed Jun 11, 2003 12:44 am

Of course you should be keeping an eye on the kiln all the time, but we have a life. I have my kiln start up while I'm at work, and I sometimes have an hour or two left in the annealing cycle when I go to bed. Other than that, I generally check on it every hour or so.

As far as fire hazards go, having a relay stick isn't all that likely to start a fire, depending on your situation. It will ruin your glass first, your shelf second and your kiln ultimately if it really gets away.

My kiln is in a detached garage, on a cement floor. If it overfires, the glass will eventually run off the shelf onto the kiln floor. Left long enough, it will burn its way through the kiln floor and pour onto the cement. None of that will start a fire. I don't think there will be enough heat generated on the outside of the kiln to light the wall on fire, or melt the electrical wire. Maybe I'm wrong.

My kiln has three elements with three contact switches, so theoretically, it would take quite a while to overfire if one sticks on. Not sure what temperature it would reach with only one element firing. It does seem as though the kiln manufacturers could build in a temperature delimiter for a reasonable price - should almost be standard equipment.

Glenda Kronke
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Postby Glenda Kronke » Wed Jun 11, 2003 11:16 am

I am probably in a slightly different situation than most because I don't work from my house, so I don't know if this is helpful to answering your question. We have 5 big kilns that are on a delay timer. They are set to run only at night (cheaper electricity rates). We also want to make sure there is no one around when the fiber paper is burning out. By the time we get here in the mornings, the ovens are in their annealing modes. We do have high temp safety shut-offs on all kilns. We also have a phone line hooked up to call us if any of the ovens fail during the night. "hello.... I'm cold. Come warm me up".

We haven't had any problems with kilns turning on by themselves or over-firing.

My not-so-helpful two cents.

glenda

GlassOrchid
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Leaving kiln on unattended

Postby GlassOrchid » Tue Jun 24, 2003 6:49 pm

I leave my kilns on and go about my business, although I leave the building and sometimes even go to sleep I don't leave the property. My studio is in the converted barn which is next to the house. I have an alarm system that includes smoke detectors. I keep fire extinguishers near my desk as well.

Some things take so long there is no alternative but to continue firing into the night. 16 hours just isn't enough daytime to get all the work done. I try to have the firing complete before bedtime or, more truthfully, adjust my bedtime to coincide with the end of the firing cycle but it doesn't always work out.

I don't recommed people do as I do but I'm still gonna do it!

~N

charlie
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Postby charlie » Tue Jun 24, 2003 7:09 pm

3 words: automatic sprinkler system

my kiln is in my garage under a sprinkler head.

Ed Cantarella
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Location: Highland, Michigan, USA

Re:

Postby Ed Cantarella » Mon Feb 26, 2018 5:02 pm

Paul Tarlow wrote:On serveral occasions I've read where people won't leave their kiln on its own on the way to full fuse -- but will leave it alone on the ramp down.

Since the controller cycles juice on and off in both directions and since the fear is that it will get stuck in the on position -- isn't the risk the same throughout the whole program?

- Paul
Absolutely Paul - exact same processes and parts at work. It's like a day job, no matter how little work you have, you're still at work.
Last edited by Ed Cantarella on Tue Feb 27, 2018 11:49 am, edited 2 times in total.
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

Ed Cantarella
Posts: 156
Joined: Mon Feb 26, 2018 3:49 pm
Location: Highland, Michigan, USA

Re: Can you Leave while the Kiln (w/Controller) is ON?

Postby Ed Cantarella » Tue Feb 27, 2018 11:17 am

Ok, here is how I did my backup system, because I am NOT going to be able to always be there or be awake during firings, That is WAAAAAAaaaay too intrusive and limiting to the creative process. Ok. Here goes

Our 3 kilns are each plugged into an individual circuit on the breaker box. Each of those breakers are GFCIs (ground fault circuit interrupters), actually CHGFs which are a GFCI and circuit breaker in the same package .
Each kiln sits on a 2" piece of Insblock 19(high temp mineral board rated for 1900f.)
A digital pyrometer probe is stuck between the Insblock and the bottom of the kiln.
The dig. pyrometer came with output that can close the circuit on an included SSR(solid state relay).(these pyrometer & SSR sets are sold on ebay for like $40-80. YMMV)
Probe gets to 900-1150f (melting in a dam at 1540f gave that higher number) depending on what I am doing in the kiln.
I have pyrometer set so that at 1250f(tested/set using peephole so probe was exposed to the higher inner temp, with kiln at 1250f :) ) it sends signal to SSR.
SSR load contacts close, causing a ground fault. May lower that to 1200f, I suspect that is plenty of leeway,
One side of the SSRs load terminals is connected to ground, the other to hot of outlet with a 10 amp slow-blow fuse in between (protects the SSR from having to take the intentional short "forever").
GFCI Breaker pops immediatly.

Cost me about $55 per kiln for a backup plan that actually works quite well. Kick me. :oops:
Ed

*Even if the SSR failed "closed", it would just trip the GFCI breaker.
**Apparently a kiln could melt itself to "death" and still not short itself out first. I have done my best to avoid that from happening.
*** I have found pictures of melted clay and glass in kilns, but none of an actual kiln bottom cooking through in a China Syndrome scenario.
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.


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