Electric Kiln with Bartlett Controller Slow Heating

[Dean]

New to site but have a question maybe someone can offer advice. We have an older Shimpo Kiln with a Bartlett V6-CF controller. The kiln has always worked great except I have changed a couple of relays in the past. Now everything seems to be working and voltage from the relays are good but the kiln is really slow heating. Like 12 hours for a Cone 5 fast glaze cycle. I checked with the top open and checked temperature with a infrared heat gun. All elements seem to be heating.

While checking with a meter I noticed the controller only operates one relay at a time. Is that normal? Do these controllers have to be replaced?

Any advice will be appreciated. 

[neilestrick]

If you have more than one thermocouple then your kiln has zones that are controlled independently of the others. If all your elements are heating but firings are slowing down, then your elements are probably worn and due for replacement. Are the element coils starting to lay over and bunch up? Also check the condition of your thermocouple(s).

[Denice]

Sounds like your elements,  a 12 hour firing  for Cone 5 isn't that bad but you couldn't call it fast.  My new L&L standard preset firing for Cone 5 is 12 hours,  my old Skutt I manually fired when I had fresh elements took 9 hours.   When the Skutt elements were just about worn out it would take 12,  I knew it was time to change them.   I haven't bothered with a quick fire on the L&L,  I am not having to run out to the garage to turn it up so a extra three hours is fine.   I decided that L&L built it they would know the best way to fire it.    Denice