Dead SSR or Bed Heater?
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Resistance is still the same as my original post. I disconnected the leads from the Power supply neutral and SSR and measured them stand alone (not connected to anything else)
-Resistance check of bed heater leads shows 14.4 ohms (120^2)/1000 = 14.4 ) when checked with multi-meter
So...how can the resistance be within tolerance or expected levels and the bed still not heat?
voltages in and out of the SSR all look good still.I'm going to go through the wires involved and dbl check connections, but I have done that already once, maybe second time is the charm? I have upped 2 images of the wiring I have done. Not my best work, try not to laugh.
-Cheers! -
My FLIR camera doesn't show any obvious issues either.
Pics of the heater bed are stone cold...as one would expect from a 6.5 mm thick slab of aluminum that isn't heating up.
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@Electriceye If you are confident in doing so, I would bypass/short your SSR and see if the bed heats. BE READY to kill it. Current is clearly not flowing or there would be a kilowatt of energy showing up somewhere. Obviously this is not a solution, but could be diagnostic.
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Have you tested your bed output with something like a fan to confirm that it's switching correctly?
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Yeah, I thought about that and remembered the circuit breaker in this room is only 15A so that would probably trip right away and might not even be enough time to see what, if anything happens.
Since this is a 120 volt mains bed heater, I'm a bit reluctant to push things too far.
Without cycling or pulsing the AC to the bed I'd be afraid it would just melt it instantly.Oh and I HATE electro shock treatments, they just ruin my day.
Thanks for the suggestion, though!
- Cheers!
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Now that's an idea... now what to hook up? Would a small appliance type fan rated at 120 volt suffice?
I have a small ULINE desktop fan I wouldn't mind sacrificing to the AC gods if need be. -
I'm suggesting you test the Duet output directly, not the SSR outputs. A DC fan that matches your VIN voltage.
Though if you're measuring the correct 120v from the SSR output already and it's switching correctly then testing the Duet output is moot.
I'd be more inclined to suspect the SSR rather than the heater itself.
What are the specs of the SSR? Do you have another to test with?
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Yep. All good points.
This leads me back to my original post findings, voltages are there...but that little LED indicator light on the SSR has never turned on, that I have seen. That puts us full circle...is it the bed heater or SSR?
Now I'm thinking you are right...it might just be the SSR.
I have a new one (different brand) and the bed heater on order already...just have to wait until they arrive. Sigh.
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@Electriceye A 1000W heater should not trip a 15amp breaker; it only draws about 8.5 amps. If your heater matches your bed mass appropriately it should not be melting instantly, either. Everything is pointing to the SSR not working.
But as @Phaedrux notes, you can attach something else to either side of the relay to test function, so long as that something else is rated for the appropriate voltage and won't pull too much current.
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Well in that case it may be a good idea to test the Duet output with a fan, just to ensure it's working properly.
For testing the 120v side you could wire up a light socket, but only if you're absolutely comfortable working with 120v.
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24 v DC fan works perfectly connected to the 24 volt side of the SSR, turning on and off as commanded by the Duet output.
Light bulb test coming up! This is really getting old, many thanks to all for the input & suggestions!
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@Electriceye looking at your picture the input wires on the SSR from the duet are reversed you may want to try reversing the polarity,
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WINNER WINNER!
Fried Chicken dinner!
You sir..are correct!
The clue I should have guessed was that the LED on the SSR was not illuminating...LEDs are polarity sensitive!The image I was going by (duet3_mini5+_v0.5-v1.02_d1.5_wiring.png) was upside down as viewed on the screen, as opposed to the direction I have it mounted. GREAT CATCH!
Board now heats up (quickly I might add) and the LED on the SSR is aglow!
jumpedwithbothfeet wins the internets today!
Thanks to ALL who had tips, suggestions and input. You people ROCK!
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