Ambient Temperature reading on kiln

[Roberta12]

Perhaps I am overthinking everything, but we replaced the #3 relay yesterday to see if that would make a difference.  (L&L e23T) While I was setting everything up to glaze and tidying my glaze space, I ran the empty kiln on fast glaze to listen to the relays and check temps.  Everything seemed fine, the new relay made a stronger clicking sound than the old one.  I ran the kiln for  1.5 hours.  Shut it off and went to bed.  I went out to the shop at noon, and the TCs say the temp is still 95.  The actual temp in that space is 60.  And usually the TCs read about 10 degrees higher than actual ambient temp.  I used my brand new digital laser thermometer on the interior of the kiln and it read 75 degrees.  I opened the kiln up, and even sitting open , in the 60 degree room, it is still reading 82 degrees.  Is this where I do the TC offset adjustment?  Or just monitor and fire to a lower cone?  What the heck?  

And where is that head banging emoji when you need it???!!

Roberta

[Bill Kielb]

If it’s just residual heat I think the room temp and kiln will equalize. Open it, give it 24 hours and everything should be close. The 75 degree surface temp you measured seems reasonably close, the thermocouples are covered and the brick has mass so the thermocouples are well imbedded into the brick and protected from the surface temperature. My thought very likely just takes time for it to cool.

Interestingly though, if you have the fully covered thermocouples, I would make sure the thermocouples are inserted into the protection tubes fully so they are lightly touching the inside front of the protection tube (fully imbedded).

When you ran it empty, did it heat evenly and what temp did it make it to? It would be nice to run an empty fast glaze program to say 1000 degrees and note the zone temps. On the way up.

[Roberta12]

@Bill KielbI actually did check to make certain the protection tube was all the way to the end of the TC.  I had read that somewhere in my exploration.  Didn't seem to make a difference.  The kiln kept reading 20 degrees warmer than the room.  True confession though, I haven't paid that much attention to that reading in recent days.   I kept mulling that over and over, and I just decided that it might not be that big of a deal.  I do have the kiln running right now with a glaze load.  Cone 5. 10 minute hold, slow glaze.  The ramp is right on at this point and all TCs are reading about the same.  

When I ran the empty fast glaze load last night, the ramp was all over the place, but I assumed that was because it was empty and trying to compensate.  The TCs were all reading pretty close.  For the first hour the ramp was 570, 96, 672,384, 472. At the end of the 1st hour the TCs were reading 736 degrees.    The next hour the ramp was 504, 528  and I shut the kiln off at 911 degrees.  

Rather like a number of things, I know just enough to be dangerous when it comes to the kiln.  Just trying to gain more knowledge. 

[Bill Kielb]

No worries. There likely are positive tc  offsets programmed in already.because of the closed end protection tubes. Neil would know from memory the common offset. They have changed a bit over time I believe. I am curious about the 10 minute hold as that should drive it towards cone 6, which might be your intention. 

As far as the ramp rates 500 - 600 degrees per hour  range is the fast glaze rate so even though sort of random, that appears appropriate. There are a couple default programming things I would be very interested in if you ever get time to check: no changes, just checking. I am assuming you have a Bartlett V6cf or “Dynatrol” as a control.

• Pid setting - percentage?
• Shut off - on or off?
• Cycle time - ## seconds?

No changes, good to write these down anyway, I have seen kilns with some pretty strange factory setups that likely were just an error during setup. The end result has been kilns that fire a bit inconsistent and oddly.

[Roberta12]

Had a 6 hour round trip today so just now unloaded the kiln.  The top shelf was 5.5 and the bottom was 6.  So, it is firing a little hotter than previously but at least I know now.  And it was fast as well.  8 hours and that included a 10 minute hold.  @Bill Kielb yes, I was trying to see if I could get to cone 6.  Without going over cone 6.  My glazes look better at cone 6 or at least more like I want them to look.  thanks for listening and responding.  More later.

r.

[Bill Kielb]

Very nice! You seem to have confirmed that relay #3 was causing some mischief. If you continue to have a half cone spread which is pretty good actually, especially in a six hour firing.  Hopefully with the infrared thermometer a quick scan after it’s been operating for a while will reveal the offenders before they become significant offenders. If you ever have a chance to get the parameters above you may be able to shave that half cone fairly easily without offsets. No guarantee but in my experience getting it right when new makes for more stabile operation throughout the life of the elements.

[neilestrick]

On 11/28/2021 at 2:21 PM, Roberta12 said:

Is this where I do the TC offset adjustment? 

Do not do the TC offset based on room temp. Only do it based on the cones. If you have the closed-end thermocouples the factory offset is 18 degrees, but in some of the older kilns it was set at something like 12 or 14 degrees.

[neilestrick]

Your kiln bricks will hold enough heat to make the room temp reading a little bit high for several days. Only after being open for 2-3 days will you get an accurate room temp reading, plus the offset. Ultimately it really doesn't matter what it's reading at room temp, though.

[Roberta12]

On 11/29/2021 at 9:01 PM, Bill Kielb said:

Very nice! You seem to have confirmed that relay #3 was causing some mischief. If you continue to have a half cone spread which is pretty good actually, especially in a six hour firing.  Hopefully with the infrared thermometer a quick scan after it’s been operating for a while will reveal the offenders before they become significant offenders. If you ever have a chance to get the parameters above you may be able to shave that half cone fairly easily without offsets. No guarantee but in my experience getting it right when new makes for more stabile operation throughout the life of the elements.

do I open the control box to check the temp on the relays with the infrared thermometer while the kiln is running?

 

[Roberta12]

23 hours ago, neilestrick said:

Your kiln bricks will hold enough heat to make the room temp reading a little bit high for several days. Only after being open for 2-3 days will you get an accurate room temp reading, plus the offset. Ultimately it really doesn't matter what it's reading at room temp, though.

That's what I decided, it didn't matter. (my deadlines have been causing panic where it was not warranted)   I have a bisque load running right now and I did put cones in to check.  You would think after 900 firings I would have done that before, but I haven't.  

[neilestrick]

19 minutes ago, Roberta12 said:

You would think after 900 firings I would have done that before, but I haven't.  

I've fired the kilns in my studio a total of about 4000 times, but I've only put cones in maybe 4 times. I use enough different glazes that I can tell if anything is firing off of where it should be.

[Bill Kielb]

50 minutes ago, Roberta12 said:

do I open the control box to check the temp on the relays with the infrared thermometer while the kiln is running?

 

Yes, unfortunately that’s probably the only way. If you are there at the very end of the firing you could shut it off open it up and scan them. They ought to stay warm for a bit. At holiday time I would scan all the kilns late during the firings to try and spot a struggling relay. This helped as five kilns would run non stop during the holidays so taking one off line with a load of half baked stuff made a mess of the schedule.

[neilestrick]

17 minutes ago, Bill Kielb said:

Yes, unfortunately that’s probably the only way.

Fortunately this is easy to do in an L&L.  Just open the outer box and there they are. ConeArt, too.

[Roberta12]

On 12/1/2021 at 10:23 AM, neilestrick said:

Fortunately this is easy to do in an L&L.  Just open the outer box and there they are. ConeArt, too.

Yeah, I can do that.  Next week!!  Unloading a glaze and another one going in.  Nothing quite like a deadline.  Again, sincere thanks to you both @neilestrick and @Bill Kielb for taking some of the heat off Rob Battey!    And yes, @neilestrick That is exactly what I have done for years, simply gone by how the glazes are looking.  I am tentatively thinking that #3 relay might have been the problem and could have been a problem for a while.  But....in the world of clay, I have learned to be patient and humble and not take myself too seriously.