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Controller advice

Posted: Tue Apr 01, 2014 3:12 pm
by Dianne Van de Carr
Last night I set up a fire polish firing, went in the house to make dinner and when I checked after a couple of hours and there was FTL on the controller and I had a meltdown. I turned the controller off and the temperature read over 1800. Of course I was devastated. This morning, after assessing the damage, I turned the controller on to see if it would start and it did. There was the distinct hum of the elements. I don't know where to start with a repair. I don't trust the controller or relay. Do you think the controller is faulty because the relay isn't stuck on or off. Advice please.
Thanks,
Dianne

Re: Controller advice

Posted: Tue Apr 01, 2014 4:37 pm
by Valerie Adams
Sounds like your relay gave out. I'd start with replacing it and go from there.

Re: Controller advice

Posted: Tue Apr 01, 2014 5:36 pm
by Dianne Van de Carr
Thanks Valerie and Brad. I will order a replacement relay. The bummer is that it is a mercury relay and I have heard that they can no longer be shipped to California. The funny thing is that the relay is clicking off and on today. I brought the kiln to 500. I seem to recall that there is some kind of patching compound I can use to reinforce the fire brick after the glass has been removed but don't remember the name. Can you help me with this also?
Dianne

Re: Controller advice

Posted: Tue Apr 01, 2014 5:46 pm
by Warren Weiss
Check that your thermocouple is ok and properly inserted. If it doesn't "feel" the heat it will tell the controller to keep heating.
Warren

Re: Controller advice

Posted: Tue Apr 01, 2014 6:25 pm
by Dianne Van de Carr
I have an "s" type thermocouple and have had a crack in the probe for a long time. I replaced the sheath in December and have fired almost daily since with no issues. Paragon doesn't think the problem is with the relay. When I got the latest mercury relay years ago I was told I had to purchase an "s" type thermocouple. Susan at Paragon said a replacement would be very pricy. Is it possible to use a regular "k" type thermocouple with the mercury relay. I didn't think to ask while still on the phone.
D

Re: Controller advice

Posted: Tue Apr 01, 2014 10:09 pm
by Buttercup
Dianne Van de Carr wrote:. I seem to recall that there is some kind of patching compound I can use to reinforce the fire brick after the glass has been removed but don't remember the name. Can you help me with this also?
Dianne
BLAKITE MORTAR
Refractory Cement & Adhesive. Ready to use paste sold by weight.
Will withstand temperatures (surface) up to 1700°c.
Used mainly for small repairs and for joining bricks (as a mortar). Blakite can also be used to glue fibreboards and tiles to bricks. Can be thinned with water for dipping mortar joint or for wash coating.
Apply thinly.
Unused mortar should be stored with a thin layer of water to prevent drying out.
Product Number: PJPA32118

This was among my notes. Sorry I have nothing more on it. Jen

Re: Controller advice

Posted: Tue Apr 01, 2014 10:30 pm
by Rick Wilton
Check your controller that it hasn't accidentally been changed from type S to K (or something else) in the settings. That will seriously mess up your controllers measuring of the temps.

The type of relay doesn't matter to the type of thermocouple, it's the controller that matters.

Some kiln controllers have type K as the default so it may have reset to K.

A type S is more commonly used in Hot glass temps like 1800f +

Re: Controller advice

Posted: Tue Apr 01, 2014 10:44 pm
by Dianne Van de Carr
Yes, we checked the settings and verified that they were for the "s"type controller. Since the s" is so much more costly, I think I'll switch back to the K type. Kind of a bummer that I was told that only an "s" type would work with the mercury relay.
D

Re: Controller advice

Posted: Wed Apr 02, 2014 10:43 am
by Bert Weiss
Dianne Van de Carr wrote:Yes, we checked the settings and verified that they were for the "s"type controller. Since the s" is so much more costly, I think I'll switch back to the K type. Kind of a bummer that I was told that only an "s" type would work with the mercury relay.
D
First, I am shocked that they let you use a mercury relay in California. Second, I have never heard of using anything but a type K thermocouple when fusing.

When it comes to Type K thermocouples, I strongly suggest you get one that is encased in an inconel sheath. An exposed end thermocouple degrades much quicker, and one in a ceramic shield is quite slow to respond to changes.