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DIY Controller not working?

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  • um, no!

    Not normal to feel current!

    measure AC voltage between the metal body of the pot and earth, its possible they are not isolated!

  • That is very difficult to say because it depends on the components used. This is the basic circuit but there are other variations.

    image

    However, what is common to all of them is that there is a cascade in the currents. There is a relatively small current flowing through the pot and the DIAC. This in turn regulates the width of the "gate" in the TRIAC through which a much greater current flows.

    reg circuit.jpg
    518 x 262 - 36K
  • Have you by change when soldering to the terminals came into connection with the body of the pot?

  • @bentstick said: Yes sir, running my 5500 watt element full tilt with a ssr@220/240 volts,the max I get is 4864 watts give or take on a 30 amp breaker dedicated to my still

    I have a pair of 120v 1650w elements in one boiler. Each shows 122v and <1500w on a kill-a-watt (with no controller). The actual current draw is somewhere around 90% - about the same % as yours.

    I'm not sure, but I think manufacturers give a "nominal wattage" to avoid potential overloading problems.

  • Remember also that the power output reduces as the temperature goes up, because the resistance increases. They probably rate the elements at a standard temperature, this could even be at a low value (0 deg C?) to maximise the rating.

  • @jonno said: Have you by change when soldering to the terminals came into connection with the body of the pot?

    Nope. Wires are only soldered to the terminals. I get the shock through pot shaft. The pot body, I have not touched as it is under the box lid.

    I rechecked the terminals and wiring on the element guard kit......all is in order, secure and no shorts. Yes, the ground wire at the element end is securely attached also.

    Anyone else's pot shaft carry a charge when full-on [ clockwise ] ?

  • That wattage was at the start of a run when the boiler temp was around 20C. And yes, it did reduce through the heat-up.

    Maybe they're rated at 0* Absolute? :))

  • Due to this thread, I have checked the pots that I have laying around here, scattered maybe the better word.
    I tested all eight of the old ones and two failed. The ohm reading was way too low to turn off the SSR.
    One even read 4K ohms! That's like having no pot at all. The last few batches of pots sent out were bought at a more reliable, read expensive, factory so the new ones should be good.
    We will not dispute anyone returning a pot as defective because there is no doubt that some are defective.

    I apologize for this. It never crossed my mind to test the ohms of potentiometers and sadly most do not pass through my hands; they are sent directly from the factory to be crated with other cartons at the port warehouse. I'll need to sort this mess out and until I do please accept my apologies for the trouble this has caused you.

    Stick with me baby, I won't make that mistake again.
    Another perhaps, but not that one.

  • Seems like the most frequent issue comes from turning the element on while the pot is at full power mostly from the pot wires been misplaced and burning the pot. Does anyone know if this will happen if the pot was set at 50% ? or will that cause it to burn as well. If it is ok, (although not recommended), then setting the pot to 50% during original first test will result in approx 50% power only regardless of which leg of the pot was used with the wiper. Then a simple clockwise and counter-clockwise turn of the pot will confirm the wiring is correct or not. This only assuming a 50% start up is not going to fry the pot as well , granted 0 % ("off position" in quotes since to me it is only off when the power is disconnected) is by far the safest for start up.

  • @Lloyd said: Due to this thread, I have checked the pots that I have laying around here, scattered maybe the better word.
    I tested all eight of the old ones and two failed. The ohm reading was way too low to turn off the SSR.
    One even read 4K ohms! That's like having no pot at all. The last few batches of pots sent out were bought at a more reliable, read expensive, factory so the new ones should be good.
    We will not dispute anyone returning a pot as defective because there is no doubt that some are defective.

    I apologize for this. It never crossed my mind to test the ohms of potentiometers and sadly most do not pass through my hands; they are sent directly from the factory to be crated with other cartons at the port warehouse. I'll need to sort this mess out and until I do please accept my apologies for the trouble this has caused you.

    Stick with me baby, I won't make that mistake again.
    Another perhaps, but not that one.

    Thank you for the kind apology , sir.

  • @captainshooch said: Seems like the most frequent issue comes from turning the element on while the pot is at full power mostly from the pot wires been misplaced and burning the pot. Does anyone know if this will happen if the pot was set at 50% ? or will that cause it to burn as well. If it is ok, (although not recommended), then setting the pot to 50% during original first test will result in approx 50% power only regardless of which leg of the pot was used with the wiper. Then a simple clockwise and counter-clockwise turn of the pot will confirm the wiring is correct or not. This only assuming a 50% start up is not going to fry the pot as well , granted 0 % ("off position" in quotes since to me it is only off when the power is disconnected) is by far the safest for start up.

    I dunno. Good thought though........ Exactly WHAT happens when a pot burns up? Does the carbon strip break? Contacts that touch the carbon burn? I took my non working pot apart to inspect it, and it looked like new, smelled like new.

    I had read that the pot must be in the off position before turning on / plugging in the SSR, and so I was careful to do this when turning it on. Might be a good post to reiterate in the DIY instruction thread however.

  • @Spokerider I posted this on the DIY controller thread also. Hope it helps, sometimes the strips can wear or even the wiper leg can get damaged.

    The Secret Life of Pots

  • Might be a good post to reiterate in the DIY instruction thread however.

    Will do, Lloyd has also had it printed on the dial stickers, so should be easy to remember.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • I just got my DIY kit today and was looking over the instructions and after looking at your pictures I noticed that you have no ground wire from the pot to the SSR, could this be the cause of your live knob?

  • More likely a defective pot. I sent, I think, about 6 batches of pots (from several different venders) to the US before any problems were noticed with the pots. I'll be checking them from now on before shipping.

  • @Lloyd said: More likely a defective pot. I sent, I think, about 6 batches of pots (from several different venders) to the US before any problems were noticed with the pots. I'll be checking them from now on before shipping.

    I hope the pots in the kits from stilldragon.com.au are ok. :/

  • Yep, different batch. I didn't test them but they should be OK.

  • This morning I plugged in my control and blew an element. I went a purchased a new one installed it and it started to heat up and was working fine and the new element blew. Not sure what the next step it. Can the SSR be the problem?

  • Seems the SSR or the pot would fail before the element?

    StillDragon North America - Your StillDragon® Distributor for North America

  • I know that is what has me baffled. The lights even went dim. I noticed an odd odor and them it blew. I pulled the cover off the controller as fast as I could and there was nothing warm in there and everything seemed to be in good condition. I just cannot imagine how I blew to elements in one morning.

  • It's not like this is the first time I used the controls.

  • I have a dead short in my SSR but I would like some sort of confirmation that that would blow heater elements before I go get another one of those.

  • I blew a couple regular 40A SSR's with an element shorted internally to ground, after I put 30A circuit breakers in for each leg, never a blown SSR... putting a fuse or circuit breaker that is a lower amperage than the SSR inline with each leg will provide near 100% protection for the SSR... I used automation direct DIN rail mount circuit breakers and am very happy..

  • Thank you I think I did the same thing. Not sure how the element grounded but it did.

  • Some common causes of elements blowing: Supply voltage too high. eg; 220v element supplied with 240v. Everything these days is made by bean counters and they tend to make everything on the limit.

    Excessive bending of the element (during manufacture or fitting) damaging the internal insulation. depends on the quality of the internal insulation.

    NB: Even if your pot and SSR were to fail short circuit this would not blow the element. The elements are designed to operate at full rated voltage (stamped on the body usually). An SSR can not 'produce' more voltage than it is supplied with.

  • unprotected: damage to the insulation --> leak --> lower resistance --> more current than SSR can handle --> blown SSR

    With circuit breaker on each leg: damage to the insulation --> leak --> lower resistance --> more current than CB permits --> CB trips

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