byjoshuawilliams Posted June 22, 2020 Report Share Posted June 22, 2020 Hi, hoping someone can give me much needed help. Recently bought an old version of the above kiln. Fitted Stafford St312 programmer and new type R thermocouple. As the same time checked all connections and changed one element. One had already been changed and other will be fine for awhile longer. Tested kiln and up until around 500c kiln ramped up fine. I had it sitting on top power to see what it can manage. Unfortunately at 600c it started to drop temp per hour until at around 850c it could only manage 40c an hour and was still dropping. Tested elements again and top and bottom heating up fine. Middle was cold however not sure if this model only uses middle at higher temperatures so am checking up to 600c now to see if it has any heat. Despite this kiln is still climbing too slowly, even at low temperatures which leads me to believe middle should be working. Contactor is clicking in and out so seems ok. Any advice on what else to check and how to check if contactor/energy regulator/interlock switch are working ok? Thanks for any help Link to comment Share on other sites More sharing options...
neilestrick Posted June 22, 2020 Report Share Posted June 22, 2020 If the middle section isn't heating, then you've probably got a dead relay or element, or possibly a bad output on the controller if you have multiple zones. If there's only one output being used on the controller (one relay/contactor), then all elements should be heating together. I've never heard of a kiln that keeps an element off until later in the firing. If you've got a meter, check for continuity on the element that's not working. It can be difficult to find a break sometimes. FYI, it's best to change all the elements at the same time, unless you have an odd one that has fried out prematurely. Doing one at a time can cause uneven heating, and you'll have problems more often as they wear or burn out one at a time. Link to comment Share on other sites More sharing options...
byjoshuawilliams Posted June 22, 2020 Author Report Share Posted June 22, 2020 Thanks for the reply. Kiln came to me from an old bloke locally with one element replaced and one spare, for some reason he only bought two. Replaced the spare one and will be buying another for the top soon. Middle element has good resistance so is fine in that respect. Kiln is only single zone. I'm leaning towards relay.I usually fire gas/soda or wood and large commercial electric kilns so the electrics on these small kilns are a bit of a learning curve! As it is there is only one contactor, the energy regulator and the interlock switch. I would have presumed that in that situation if the relay etc was gone no elements would fire up? There would just be one relay in the contactor is that right? I might try and replace the contactor for peace of mind and go from there. Link to comment Share on other sites More sharing options...
neilestrick Posted June 22, 2020 Report Share Posted June 22, 2020 41 minutes ago, byjoshuawilliams said: Thanks for the reply. Kiln came to me from an old bloke locally with one element replaced and one spare, for some reason he only bought two. Replaced the spare one and will be buying another for the top soon. Middle element has good resistance so is fine in that respect. Kiln is only single zone. I'm leaning towards relay.I usually fire gas/soda or wood and large commercial electric kilns so the electrics on these small kilns are a bit of a learning curve! As it is there is only one contactor, the energy regulator and the interlock switch. I would have presumed that in that situation if the relay etc was gone no elements would fire up? There would just be one relay in the contactor is that right? I might try and replace the contactor for peace of mind and go from there. Correct, if the contactor was the problem then none of the elements would work. What is an energy regulator? Do you mean a power transformer for the controller? Using a meter, trace the power flow and see where it stops. Could be the previous owner wired it wrong? Do you have a wiring diagram for reference? Link to comment Share on other sites More sharing options...
byjoshuawilliams Posted June 22, 2020 Author Report Share Posted June 22, 2020 Energy regulator for the old fashioned manual power dial. Yeah I'll give that a go. The nut which holds the 'key' for the interlock switch is rusted tight so without removing that I have no way to work on the wiring whilst live. Although I presume that bypassing the interlock switch and temporarily splicing the wires together would achieve the same result. Previous owner said he had it up to 1100c fine although he is old so might be forgetting something. However I'd have thought the only wiring issues which would result in one element failure would be within that elements circuit and each element circuit is correct and the same. As you say if I follow the circuit with a meter I might find a small fault I can't see ATM. I would attach some photos but can't seem to get them down to the forum limit on my phone. Problem with high data photos and low forum limits! Link to comment Share on other sites More sharing options...
neilestrick Posted June 22, 2020 Report Share Posted June 22, 2020 6 minutes ago, byjoshuawilliams said: Energy regulator for the old fashioned manual power dial. So it has a manual dial in addition to the digital controller? That could be the source fo the problem, as it may cut out an element on medium or low setting. Link to comment Share on other sites More sharing options...
byjoshuawilliams Posted June 22, 2020 Author Report Share Posted June 22, 2020 Yeah I had that thought. I need to check it is on high once I get above 300-400c. I might just bypass it to negate any issued Link to comment Share on other sites More sharing options...
Chilly Posted June 23, 2020 Report Share Posted June 23, 2020 19 hours ago, byjoshuawilliams said: I would attach some photos but can't seem to get them down to the forum limit on my phone. Problem with high data photos and low forum limits! I use Outlook for e-mail. If I email photos to myself (without actually needing to click send) Outlook asks if I want to reduce the file size. I'm sure other mail programmes are capable of the same. Link to comment Share on other sites More sharing options...
Tamsingifford Posted May 19, 2021 Report Share Posted May 19, 2021 @byjoshuawilliams Hello I know this is an old thread, but I also have a VERY old P5975 pottery crafts kiln and was wondering if yiu have a wiring diagram for it, I have no manual and am having my first problem with it since I got it 5 years ago, which would be made so much easier with a map! Thank you any help hugely appreciated Tamsin Link to comment Share on other sites More sharing options...
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