120v RIMS controller build problem

[jmfitzgerald]

So I've built a fairly simple RIMS controller with a lot of input and research from other builds on this forum. It's up and working except for one minor issue that I'm kinda stumped with, and think I just must be missing something simple? I know it may be a bit hard to troubleshoot without a schematic, but it's very straight ahead and I'll try to post something when I can.

I have an "element" LED across the element outlet after the SSR. When the element is not on, via the PID and SSR, the LED still glows faint, and I'm still getting 43V across the outlet. If I take the LED out of the circuit, all works perfectly fine, line voltage either full on and full off as I'd expect from the SSR. I just don't understand why with the LED in line, and the SSR not engaged, where the 43V is coming from. Any thoughts?
View attachment ImageUploadedByHome Brew1447643604.538021.jpg

 

[saazall]

SSR typically do not turn completely off. There is always residual power coming through. Not sure if the 43V is common, mine runs around 36. This is why most panel build circuits call out a contactor to open the line from the SSR to the outside of the control box.

 

[PlexVector]

The technical term is leakage current. Usually 1mA to 10mA, and this is enough to light-up high efficiency LEDs. Try increasing the bias resistor to the LED until is is not noticeable, then when power is applied it should still be bright enough.

 

[jmfitzgerald]

Here's a rough sketch of how it's wired. The LEDs are the 120v Pilot LEDs from Electric Brewing Supply. Still seems weird that I can meter 43v on the outlet with this LED in line, and if I take it out of the circuit, I get <0v. View attachment ImageUploadedByHome Brew1447649567.544178.jpg

 

[BrunDog]

If you are getting the voltage without an element plugged in, this is normal. Plug the element in and the LED should go out. If it doesn't, then carefully see if your element is heating up. If it is, your SSR is misbehaving.

-BD

 

[jmfitzgerald]

yep, stilly me... i've been testing this with no load on it, and it's been working perfectly this whole time!!! i just put a desk lamp on the output, and it's either on or off, same with the LED, not half lit!

i knew it had to be something simple, as it's a very simple circuit. thanks to this forum! now time time do a leak test and fire up the RIMS tube!