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Oven Built: Looking to Wire. Wiring Diagram Attached for Review

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  • #31
    Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

    I might be so me kind of old fashion but I never used ssr relay . I used the good old noisy contactor , yes the clicking noise is pretty loud but I installed a good quality contactor no heatsink , no fan, no problem ,and that contactor has served for three years full time before I sold the oven and was still working fine .
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    baz

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    • #32
      Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

      Well, I've got it regulating at 400! Replaced the ssr, found some thermal compound and wired up some new fans and it works. (sorta)

      In order for it to work, I need to heat it up to 401, turn off the pid, unplug oven, plug back in, turn on pid (in that order) or else the thing just stays glowing full power. But as soon as I do that process, it regulates perfectly. So while I don't fully understand it, I'm very happy and I think I'm ready to actually start doing some powdercoating instead of troubleshooting.

      Thanks again to both of you for your help through all this troubleshooting

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      • #33
        Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

        Obviously something is malfunctioning if you're required to go through this process. It shouldn't be that difficult to troubleshoot. There are only a couple of possibilities. The process is fairly simple in that when the set temp is approached the pid should begin cycling the relay on/off. You can observe this by looking at the pid's lights. It isn't that unusual for the actual temp to exceed the set temp by a few degrees. If the pid's lights do not reflect it cycling the relay then the pid is malfunctioning. If it is then observe the ssr which should also have an indicator light. Is the ssr's indicator light cycling on/off?

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        • #34
          Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

          Yes, that is why I am confused.

          The lights on both the PID and the RELAY begin to flash as it approaches target temperature, yet the elements stay full power. Likewise, both lights completely go out once the target temperature is exceeded, yet the elements stay on full power.
          Completing the process described in my above post however allows the elements to go off and then after that process is complete, the elements respond to what the PID/SSR is telling them: they dim accordingly and shut off accordingly to match the set temp.

          It is almost as if once the elements go full power, they can't come off full power without the power cycle. To me, that makes no sense because they should either be getting electricity or not (in my head at least): but I'm just reporting what I am seeing lol.

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          • #35
            Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

            Originally posted by KoreyI View Post
            Yes, that is why I am confused.

            The lights on both the PID and the RELAY begin to flash as it approaches target temperature, yet the elements stay full power. Likewise, both lights completely go out once the target temperature is exceeded, yet the elements stay on full power.
            Completing the process described in my above post however allows the elements to go off and then after that process is complete, the elements respond to what the PID/SSR is telling them: they dim accordingly and shut off accordingly to match the set temp.

            It is almost as if once the elements go full power, they can't come off full power without the power cycle. To me, that makes no sense because they should either be getting electricity or not (in my head at least): but I'm just reporting what I am seeing lol.
            Your elements are not supposed to dim . they should be on or off . i think you should still find your problem if not then you should take down the whole electric part of your oven and start from scratch because you do have a problem somewhere and until you find it you do not know if that problem could turn into a short , a fire or worse someone could get a Deadly shock from your oven.
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            baz

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            • #36
              Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

              It's not that I doubt what you are seeing, but when that condition occurs a simple test or two should determine what component is failing. I also agree with baz in that something is wrong here and should be addressed. Check the voltage from the load(element) side of the ssr output to ground when the lights are out. If it reads 240 volts then the ssr relay is not functioning correctly. If it reads 120 volts then it's fine and the elements should not be energized. If they are then you have a wiring problem else where. Also check the DC voltage across the ssr's input terminals. If there is voltage when the lights are out the pid is malfunctioning.

              As baz has noted, for safety sake you need to figure out what is wrong here and not use the work around that you posted.

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              • #37
                Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

                Ah - as much as I hate to mess with it more I guess you're both right. I will take additional voltage readings both before and after I complete the specified process and get it regulating properly to see what is going on. I think I have figured out a way to measure across the elements without cutting a hole in the side panel of the oven. I figured that if this was a wiring problem / short, the problem would persist regardless of whether or not I plugged/reset the oven according to the process above.

                With regards to the elements dimming: I didn't mean it literally - I just meant they are dimming because they are never getting 240v long enough to get back to full glow, so they "appear" dimmed, even though they are technically off or not.

                I did notice something strange with regards to the PID: When the lights go off, my voltage meter is reporting 0.20 VDC across the input terminals of the SSR. Other times, it is reading 0.00 VDC. Is the 0.20 VDC enough to trigger the relay? Even if it were, I am not 100% sure without additional volt testing that the 0.20 versus 0.00 is coinciding correctly with when the oven is regulating versus not regulating. Won't be able to check until Thursday at the earliest, but I'll report back with all the info I can gather up.

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                • #38
                  Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

                  I've actually given you some bad information as far as testing the ssr goes. I thought my answer was obvious, but decided to do a quick test anyway and discovered something I was unaware of. In testing the ssr if the output relay is open then testing either side to ground will give you a reading of 120 volts. Testing across the two output terminals gives you a reading of 240 volts. Where I was wrong is that if the ssr output side relay is closed which is the condition it's in when calling for heat and you do a voltage test across the two ssr output terminals(line and load) you will get a reading of zero volts, not 240V as I expected. Apparently the internal switching via the SCR or triac makes the multimeter think there is zero voltage!

                  As for the question about the input voltage, most ssr's can switch if the control voltage is somewhere between 3-32VDC.

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                  • #39
                    Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

                    Originally posted by ed_denu View Post
                    I've actually given you some bad information as far as testing the ssr goes. I thought my answer was obvious, but decided to do a quick test anyway and discovered something I was unaware of. In testing the ssr if the output relay is open then testing either side to ground will give you a reading of 120 volts. Testing across the two output terminals gives you a reading of 240 volts. Where I was wrong is that if the ssr output side relay is closed which is the condition it's in when calling for heat and you do a voltage test across the two ssr output terminals(line and load) you will get a reading of zero volts, not 240V as I expected. Apparently the internal switching via the SCR or triac makes the multimeter think there is zero voltage!

                    As for the question about the input voltage, most ssr's can switch if the control voltage is somewhere between 3-32VDC.
                    Yes, this is the behavior I have observed in my testing. Regardless of whether SSR is open or closed, I always see 120 volts on one output and ground. Testing across the SSR output terminals yields zero volts. If im understanding correctly, though, I should see 240 volts across the element terminals when the relay is calling for heat and only 120v when it is not calling for heat. I don't have access to the element terminals easily since they are inside the oven, but I am assuming I can check the voltage across the wires at the wire junctions for the parallel wiring. Those are less difficult to access given that they are only inside electrical conduit instead of behind the sheet metal.

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                    • #40
                      Re: Oven Built: Looking to Wire. Wiring Diagram Attached for Review

                      Originally posted by KoreyI View Post
                      Yes, this is the behavior I have observed in my testing. Regardless of whether SSR is open or closed, I always see 120 volts on one output and ground. Yes, that is correct. Testing across the SSR output terminals yields zero volts. Correct, when testing the ssr's output terminals you should see zero volts when the pid/ssr is calling for heat and the elements are energized, 240 volts across the ssr's output terminals when the ssr is not calling for heat. If im understanding correctly, though, I should see 240 volts across the element terminals when the relay is calling for heat no, zero volts when calling for heat. and only 120v when it is not calling for heat. 120V from either terminal to ground. I don't have access to the element terminals easily since they are inside the oven, but I am assuming I can check the voltage across the wires at the wire junctions for the parallel wiring. Yes, but use caution when having the wire connections exposed for testing. Those are less difficult to access given that they are only inside electrical conduit instead of behind the sheet metal.
                      see comments in red

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                      • #41
                        I Know this is an old thread but did you sort it out as I'm having the same trouble after building mine ' I'm going to check all the wiring tomorrow and do some testing with the multimeter.
                        sorry for a first post but I came across this thread when looking for my problem .

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