DanB Posted November 24, 2016 Report Share Posted November 24, 2016 I'm new to this, I'm trying to help with Kiln repair. My friends have an L&L easy fire kiln. Last firing it could not get up to temp. It seems to me the middle elements are not getting power, it appears the relay is the problem. The relay is a double pole relay. (does it need to be?) Checking with a meter, half the relay still works. My thought is to just bypass the other half so that one side of the relay could energize the element. I wonder why they are double pole relays to begin with, I'm inclined to parallel the poles for all the elements so that there is redundancy. Meaning... one end of the element is always connected to 240V, the other end is turned on and off by the relay. I don't understand why why two connections are necessary. Link to comment Share on other sites More sharing options...
Dick White Posted November 26, 2016 Report Share Posted November 26, 2016 If you do not understand basic high voltage electrical theory and practice for kiln operations, you should not be trying to "repair" a kiln by hotwiring the relay. If a relay is broken (which is fairly common), then it should be replaced with a similar relay. Because you have already demonstrated that you don't know how a kiln or its relays work, you should buy the new exact replacement relay from a reputable ceramic supplier or kiln repair shop. Do not try to pick out a new one yourself, you will probably pick out the wrong one. Replacing a relay is fairly simple - a couple of screws hold it in place and just swap the wires from the old broken one onto the same terminals on the replacement, and then mount the new one back in the same place with the same screws. Link to comment Share on other sites More sharing options...
neilestrick Posted November 26, 2016 Report Share Posted November 26, 2016 It's a major safety hazard to always have one leg hot. If you were to touch an element while loading or unloading the kiln you would complete the circuit and get a shock. As a repair person, I would be super pissed off to find that on a kiln I was working on. I've gotten shocks before on kilns where someone did something dangerous with the wiring, and it isn't fun. There's a reason they build the kilns the way they do- they aren't going to complicate the system if it's not necessary. Link to comment Share on other sites More sharing options...
DanB Posted November 27, 2016 Author Report Share Posted November 27, 2016 Dick... nice to hear from you that relay malfunction is common. I know my way around high voltage, nice to know that relay malfunction is common. Neil ~ thanks, that explains a lot and makes a load of sense. Ordering relays on Monday ;-). I suppose it's good practice to replace them all if one failed? Thank you both. Link to comment Share on other sites More sharing options...
Dick White Posted November 27, 2016 Report Share Posted November 27, 2016 240V and kiln control operations are 2 separate, albeit interrelated, bodies of knowledge. If kiln elements could be safely controlled with a single pole switch, the manufacturers would build them that way. And yes, sometimes people replace all the relays at the same time. It's a bit like multiple bulbs in a difficult to reach light fixture. The next one will blow out too so you might as well replace them all while you have the ladder out. Link to comment Share on other sites More sharing options...
neilestrick Posted November 27, 2016 Report Share Posted November 27, 2016 If they all have at least a couple hundred firings on them, then go ahead and replace them all. Otherwise just do the one. Put the date on the new one with a Sharpie, and make a note somewhere (I use the calendar on my computer) of the date and number of firings when you change it. The when it dies again you can see how long it's lasted. Link to comment Share on other sites More sharing options...
DanB Posted November 27, 2016 Author Report Share Posted November 27, 2016 I appreciate your input Dick and Niel. I'm a newbie to this stuff but have a grip on herding electrons and measuring stuff. My expertise is off grid power systems and I've recently moved to a place where maybe I'm the most qualified person to maintain kilns. This kiln is at about 90 firings since new. In my experience when one thing fails replace them all (relays). And also elements... They all still work but they're getting bunched up. I wonder if best practice is to replace them all soon. It seems quite expensive and sad when the kiln fails around here. Link to comment Share on other sites More sharing options...
Dick White Posted November 27, 2016 Report Share Posted November 27, 2016 The best test for the elements is with an ohm meter. They may look all bunched up but still have some life. Or maybe they are shot. The only way to be sure is test each set for their resistance. The proper resistance per element (and half that value for the pair in each section) is listed in a table in the owner's manual. If you don't have access to the manual, let us know the exact model of the kiln and we can look it up for you. The easiest place to test is right there on the relays while you have it open - put the meter probes on the load wires going out to the elements and that will pick up both elements in the target section. If the element resistance is 10%+ above the specification, then the elements are beginning to fail and should be replaced. Link to comment Share on other sites More sharing options...
neilestrick Posted November 28, 2016 Report Share Posted November 28, 2016 At 90 firings you shouldn't need to replace all the relays. Like Dick said, the elements may or may not need replacing. Check the resistance. I would expect to see closer to 150 firings if you're doing a combination of cone 6 and bisque. Link to comment Share on other sites More sharing options...
chezzi64 Posted October 31, 2018 Report Share Posted October 31, 2018 Hello neilestrick, can I ask your advice please? I have an L&L kiln that has done just over 50 firings. However I've already replaced all 4 elements. Now the supplier suggested that my relays may be failing. Is this to be expected after so few bisque and cone 6 firings? Thanks Link to comment Share on other sites More sharing options...
neilestrick Posted October 31, 2018 Report Share Posted October 31, 2018 1 hour ago, chezzi64 said: Hello neilestrick, can I ask your advice please? I have an L&L kiln that has done just over 50 firings. However I've already replaced all 4 elements. Now the supplier suggested that my relays may be failing. Is this to be expected after so few bisque and cone 6 firings? Thanks That should not be the case. What model, voltage and phase is the kiln? Are you using a downdraft vent? What type of clay are you firing? Is the room vented for heat? Link to comment Share on other sites More sharing options...
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