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Is My Gare Pf2329 Kiln A Lemon?

Kiln cone 6 under firing evenheat

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#1 Naomi

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Posted 20 April 2014 - 09:08 PM

I bought a used Gare Pf 2329 kiln a few months ago. It was in great physical shape. It's 240 v single phase but we had it installed on a 208 power supply (by a certified electrician) and changed the elements to 208 volt (by a very experienced kiln repairman). He tested the power using a meter and it should have worked. We tried firing to cone 6 but after 19 hours the cones bent (and my glazes begged for the heat to stop, but that's another story). Obviously something was wrong. We had the relays checked and one changed. He also added an extra one since one relay was controlling 4 elements. We successfully did a bisque firing. Today we started a cone 6 firing at 5 am. It was going up well until about 1900 at 12pm, when it started slowing down big time. It was inching up for hours and stalled around cone 1. We turned it off at 9 pm.
I can't believe it's still not working properly. The last things are the thermocouple or the controller. The repairman says the thermocouple is fine. We need to call him again. I imagine the next thing he'll check is the controller. These repairs are going to end up costing the same as the kiln did in the first place. But we've invested too much to turn back. I am so frustrated! Any suggestions? Similar stories?
I need to fire my work! My work is being showcased in a boutique in little over a week and I can't afford to lose any more pieces to bad firings.

#2 High Bridge Pottery

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Posted 21 April 2014 - 05:26 AM

Sounds to me like you don't have enough power going to the kiln. If the bisque worked fine I don't see why the thermo or controller would be broken.

 

How many elements does your kiln have? On mine I have two relays with 4 elements on one and 6 on the other so not sure why you needed the extra relay. By adding the extra relay have you not halved the amps going through those 4 elements. Are those 4 elements wired up in series or parallel pairs?

 

A wiring diagram could be helpful if you have one.


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#3 JBaymore

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Posted 21 April 2014 - 08:24 AM

Did you program in a firing curve, or are you using a "stock" program loaded into the computer by the manufacturer?

 

Have you checked the programming if it is one YOU input?  Maybe you messed up the rate per hour for the upper pat of the cycle? 

 

best,

 

......................john


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#4 Naomi

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Posted 21 April 2014 - 08:59 AM

Not sure which question to answer first. It does indeed sound like there's not enough power. A 60 amp circuit was installed in the fuse box and that leads to a breaker box with the appropriate 60 fuses. Maybe we should call th electrician back.
As for the relays, there were 3, one for he top element, one for he bottom element, and one for the 4 center elements. That meant one relay worked 4 elements. Now the center elements are split up into 2 and 2. The wiring is all done according to the diagrams provided with the kiln.
The perfect fire controller is first generation and super basic. The rate/hr was set at 500. It just won't seem to go above 1900 without slowing and stalling, not reaching temp.

#5 neilestrick

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Posted 21 April 2014 - 09:17 AM

First, adding another relay won't help anything. A relay can run many elements as long as the amperage draw is not more than the relay can handle. So I'm not sure why your repair guy did that unless it was called for by the wiring diagram. Post the wiring diagram so we can take a look at it. Can't do much without more information.


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#6 Wyndham

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Posted 21 April 2014 - 09:29 AM

I would check with Evenheat, the mfg's in case you may have the wrong elements. The electrician can measure the amps and voltage under load condition and see if you have enough power for the temp your going to.

It's possible that those elements are not rated for cone 6, that's why  the mfg can advise you about that.

Is the service line coming in sufficient for the amps needed?

Double check the controller programs as advised by John.

Just a guess but it sounds like maybe 2 of the 4 elements or all 4 are not getting full power, the kiln can get to bisk but not enough juice to get to cone 6 at the correct rate of firing

 Wyndham



#7 High Bridge Pottery

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Posted 21 April 2014 - 09:45 AM

A 60amp circuit sound like more than enough but the kiln will only draw as much power as the elements dictate.

 

Sounds like something went wrong in the element/relay replacement that has messed up how much power the circuit draws.


                                                                                                                 1384226_215924051918490_1181728069_n.jpg


#8 JBaymore

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Posted 21 April 2014 - 09:57 AM

Like Neil, I find the "added a relay" concept a bit strange.  If the kiln was OK manufacturering wise to start with........ why do that.

 

Unless it was a case of at 240 it did not need the elements wired in the same way... but at 208 it did......... and the shell was set up for wiring it for either option.  But that is not common that I know of.

 

If it weren't "screwing up" BEFORE the added relay "fix".... I'd be thinking of that being the culprit.

 

It is only 45 Amps max draw... so the 60 Amp service should be fine.  Hum........ how far (feet) is the kiln from the main supply box (not a sub kiln only box), and what guage wire did the "certified electrician" use for the run from the box to the kiln?

 

best,

 

....................john


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Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

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#9 neilestrick

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Posted 21 April 2014 - 02:38 PM

This is really difficult to diagnose without being there in person. Assuming everything is wired up correctly (which I'm doubtful of at this point), you're going to have to put a meter on it and test element resistance, voltage and amperage.

 

It's quite possible that you've got a controller issue. A controller that old could well be having problems, in which case it will need to be replaced. It could also be a case of electrical noise. I've seen a couple of kilns stall out around 1900F due to that. One possible solution on newer controllers is to add a grounding wire from the center tap terminal of the controller to the main ground in the controller box.


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#10 Wyndham

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Posted 22 April 2014 - 09:58 AM

I thought I had posted this yesterday but must have missed the post button, anyway.

Type K thermocouples can get flaky as they age. A T/C may work at room temp or get up into the 2000 deg range but may be faulty at cone 6.

A new T/C is about $50 and maybe an easy fix.

Wyndham



#11 neilestrick

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Posted 22 April 2014 - 10:43 AM

I thought I had posted this yesterday but must have missed the post button, anyway.

Type K thermocouples can get flaky as they age. A T/C may work at room temp or get up into the 2000 deg range but may be faulty at cone 6.

A new T/C is about $50 and maybe an easy fix.

Wyndham

 

Excellent point. A new thermocouple could be as cheap as $15 depending on which type you have. It would be worth trying a new one. Also inspect the thermocouple wire.


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#12 Arnold Howard

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Posted 24 April 2014 - 08:51 AM

I bought a used Gare Pf 2329 kiln a few months ago. It was in great physical shape. It's 240 v single phase but we had it installed on a 208 power supply (by a certified electrician) and changed the elements to 208 volt (by a very experienced kiln repairman). He tested the power using a meter and it should have worked. We tried firing to cone 6 but after 19 hours the cones bent (and my glazes begged for the heat to stop, but that's another story). Obviously something was wrong. We had the relays checked and one changed. He also added an extra one since one relay was controlling 4 elements. We successfully did a bisque firing. Today we started a cone 6 firing at 5 am. It was going up well until about 1900 at 12pm, when it started slowing down big time. It was inching up for hours and stalled around cone 1. We turned it off at 9 pm.

The relays make a clicking noise and the elements hum when they receive power. At 1900F, could you still hear the relays click?

 

Sincerely,

 

Arnold Howard

Paragon Industries, L.P., Mesquite, Texas USA

ahoward@paragonweb.com / www.paragonweb.com



#13 Naomi

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Posted 02 May 2014 - 08:18 PM

The relays are not clicking. The kiln is struggling to raise the temp but it just doesn't seem to be getting enough....

The elements are definitely good. I have been in touch with evenheat and we have the right ones. As we are looking at  phase 208 service, we  got those elements. We are using a three phase breaker as well in the box. 

We ran the kiln without the controller and it had the same issue...it slowed down measurably at 1900 and stalled until 2040 or so. We were also using a pyrometer and the temp was off by about 60 degrees (thermocouple read lower than the pyrometer). We also measured the amps and volts and everything was within range. 

Basically what I'm ending up are a series of holds that I do not want. I want the temperature to continue to rise to cone 6 or thereabouts.

I am wondering if it is an issue with the dry transformer in my studio. I'm seriously at a loss. 

Thank you all for your replies!



#14 Wyndham

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Posted 02 May 2014 - 09:43 PM

The relays are not clicking. The kiln is struggling to raise the temp but it just doesn't seem to be getting enough....

The elements are definitely good. I have been in touch with evenheat and we have the right ones. As we are looking at  phase 208 service, we  got those elements. We are using a three phase breaker as well in the box. 

We ran the kiln without the controller and it had the same issue...it slowed down measurably at 1900 and stalled until 2040 or so. We were also using a pyrometer and the temp was off by about 60 degrees (thermocouple read lower than the pyrometer). We also measured the amps and volts and everything was within range. 

Basically what I'm ending up are a series of holds that I do not want. I want the temperature to continue to rise to cone 6 or thereabouts.

I am wondering if it is an issue with the dry transformer in my studio. I'm seriously at a loss. 

Thank you all for your replies!

"We tried firing to cone 6 but after 19 hours the cones bent (and my glazes begged for the heat to stop, but that's another story)".

 

Does this mean that the glaze overfired?

 

Here's one thing that maybe happening. The kiln is firing at max but the thremocouple fails at about what it thinks is 1900 deg but the computer controller is keeping the power on, hence the relys are not clicking because the power is at max. The T/C can not read any high temp because it is old and a crack in the weld creates a point(short) that shows only that temp.

If you fire the kiln and have a series of cones that you can see through the peep holes starting with cone 08, then 06 then 04 in a 3 cone cone pack and another cone pack with cones 4, 5, 6, then record the tine from start to a point in time where cone 6 should fall (evenheat should have a chart of about how many hrs the controller is programmed for fire to.

 

Or if the cones do not bend at around the time/temp that the chart calls for AND the relays are good and wired properly, then the controller is faulty.

 

There are several wires that come from the controller to the relays, these carry a 12 volt signal that turns the relays on and off. One each for power, such as red, yellow, and white and one ground wire common to the relays, this is usually black.

If any of these are burned or bare, it may short the signal out,  preventing one or more of the relays from working. Sometime one of these wires may touch the hot metal of the kiln jacket and short or burn out.

 

If these wires are making the proper connection then the controller it self may be the issue. Also check where the T/C is attached to the controller and make sure the screw is tight where it is connected to the T/C wire on the controller.

 

I can't think of any other possibilities right now

Wyndham



#15 Naomi

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Posted 02 May 2014 - 10:33 PM

Yes, it over fired certain of my pieces. 

I'm thinking about what you're suggesting, but we ran the kiln bypassing the controller and it did the same thing. The thermocouple was reading the temp but we didn't run a program, just went straight to high, seeing whether it would act up around the 1900 mark, and it did. 

The relays have all been checked.

The latest firing took 12 1/2 hours (an improvement!) and I was checking the cones to see when they bent. Again, it took a very long time for them to bend and I ended up with over fired underglazes because of the hold/soak.

I'm appreciating the brainstorming here because I just don't know what to do. 



#16 Wyndham

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Posted 03 May 2014 - 06:20 PM

OK, when you say that you bypassed the controller, what exactly did you do. If you chose a preprogramed feature like "fast glaze fire" or any other preprogramed feature to a certain cone like cone 6, then that is a program and that relies on information from the T/C.

On my olympic computer controlled kiln, I can not fire the kiln without using the controller.

Could you list step by step how you fired the kiln.

Wyndham



#17 Naomi

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Posted 04 May 2014 - 01:10 PM

My kiln tech did it. Basically he disabled the controller and the kiln just went up in temp without being programmed. The TC was registering but that was it.
We successfully did a bisque, which was programmed at 06 but cones showed an 05.
The TC read 1805. i am willing to make adjustments but for cone 6, it stalls too long and overfires some of my glazes. And that is with me waiting for the cone to bend. So I'm finding it difficult to determine what temp to set it to. If i set it to 2232 it will just keep firing. Do i set it lower?
I'm pulling my hair out here.

#18 Arnold Howard

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Posted 05 May 2014 - 04:56 PM

We successfully did a bisque, which was programmed at 06 but cones showed an 05.
The TC read 1805. i am willing to make adjustments but for cone 6, it stalls too long and overfires some of my glazes. And that is with me waiting for the cone to bend. So I'm finding it difficult to determine what temp to set it to. If i set it to 2232 it will just keep firing. Do i set it lower?

Yes, program the kiln to a lower temperature. Can you tell how much the glazes overfired? If not, program to 2175F as a starting point. Adjust the temperature with each firing until your glazes turn out the way you want.

 

I would double check the amperage that your kiln is drawing under load, and the line voltage. If the kiln is getting enough power, then make sure the lid isn't rising at higher temperatures.

 

Sincerely,

 

Arnold Howard

Paragon Industries, L.P.







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