used kiln replaced elements still not getting hot enough

[ericapocalypse1]

I purchased a used Cress b23h kiln.  I have fired it about a dozen times.  The kiln sitter has shut it off twice.  one of those times it took 19 hours before it happened.  The other time it took about 16 hours.  I shut it off manually the other times at about 16 hours and only one of those times it appeared to at least be hot enough for the glaze to melt properly.  The voltage going into the kiln appears to be at the required 240V.  The elements were reading 8ohm.  I live in the middle of Wyoming and there is nobody nearby who services kilns that I am aware of.  I purchased and installed new elements and ran the kiln empty.  Well my boyfriend did and put the cone in the sitter vertically, so I turned it off manually after ten hours cause the sitter wouldn't be able to.  Yesterday I loaded the kiln with the cone put in the sitter properly and it ran for 19 hours before I shut it off.  I haven't see what's happened in there yet.  The new elements read at 11ohm.  I did notice with the old elements and the new ones that I can hear them click on and off when the dial is set at lower temperatures, but I do not hear them doing it at the higher ones.  Could it be a relay issue or something else?  I have no clue.

thanks

[Bill Kielb]

just a quick glance at this
First question - what cone are you firing this to? This kiln appears to fire cone 6 maximum and also appears to have been designed originally for 230V. At 230 v the original elements would have been designed for about 9.5 ohms to draw 24 amps and provide 6kw of heating energy. (Not a lot) new elements for todays 240 v mains voltage would be about 10 ohms to provide the approx same 24 amps and 6 kw of heating energy. So everything you have said sort of aligns with expectations reasonably.

This kiln will have a very difficult time achieving cone 6, especially repeatedly and especially if the new elements are a touch high in resistance. It would appear this kiln is best used for lowfire work … cone 04 type firings.

your likely wiring diagram here (Cress web page link appears broken when you click on it, shows up located as below) http://www.cressmfg.com/wp-content/uploads/B23H-240-VAC.pdf

This kiln uses infinite switches and does not have relays. The original 8 ohm elements more closely match a 208v kiln - is this a conversion from 208v to 240v?

 

Edited Sunday at 11:59 PM by Bill Kielb

[neilestrick]

What does the serial plate say regarding voltage and max temp?

Are all the elements heating? Run a paper test- put a little piece of paper on each element, turn it on high for a couple minutes and see if all the papers burn.