Originally Posted by ChuckO
When there is no input signal and no load on an SSR you will see the line voltage on the output. As soon as you plug in the heating element you should see the voltage drop to zero.
I'll bet that you have the pump plugged in and are looking at the voltage on the other side of the duplex outlet. Unplug the pump and then measure the outlet. You will probably have 120v there.
Originally Posted by Walker
right... there is leakage current ion an SSR. It's always there when the SSR is 'off'. A meter will give you very strange readings if you have no load connected to the output of the SSR because of that leakage current.
Thanks guys! That explains half of my conundrum, that explained the weird readings I was getting before.
BUT... now that I was confident in my panel wiring and setup I started running a wet test. During the test I started experiencing another related issue, that I was able to confirm with my multimeter. When the load (element) was attached to the relay and none of the relays were triggered there was no current draw on any of the circuits. But when the brewtroller would trigger the relay for the pump, the circuit for the element would close as well without the brewtroller closing the control side of the relay, when this would happen I would see about a 16a draw on the "hot" side of the relay, and the diagnostic led on the relay would not light.
After much frustration, I calmed down had a few homebrews
and traced it back to faulty transistor array on the brewtroller. When it would trigger the pump relay it would leak enough current to trigger the element relay, but not enough to light the diagnostic LED. I swapped it with one of the others on the board and the problem disappeared!!
I would not have thought to look there without your help, I had no idea that without a load a SSR leaked. Thanks Guys!