SSR weirdness help--SSR latches when I plug in element?

[BetterSense]

I think I may have some sort of ground loop, or other gross conceptual failure relating to my AC wiring.

I'm building a simple 30A control box with an SSR. I have a microcontroller to generate PWM for the SSR. Very simple. However it doesn't seem to be working right.

I have wired up both a 240V 30A receptacle for the heating element, and a 120V 20A receptacle for running my pump. I decided to make the 20A receptacle 'dimmable' like the 30A one, just in case I ever want to control a 120V something in the future.

When I plug a 100W light bulb into the 120V receptacle, it appears to work fine. The light blinks on and off in a very PWM-y fashion. However when I plug in the heating element, the light bulb then comes on and stays on. Then I get scared and turn the switch off.

I tried to draw the circuit here:
https://www.circuitlab.com/circuit/jzmfje/brewtroller/

I also uploaded a pic if it helps.

Any idea what could cause this behavior?

 

[AllanMar]

The heating element will be feeding 115V through the element and thru the light bulb to neutral even with the SSR off. Think of the heating element as a 10ohm resistor and look at your circuit, your essencially putting a 10ohm resistor between "phase Y" and your 115V outlet.

 

[BetterSense]

I think i get it now. I will just give up on my 120v receptacle being 'dimmable'. Unless someone can come up with a way to achieve that.

 

[Walker]

I think I understand what you are trying to do, and I think I can offer a suggestion.

My assumptions about how you want to currently use this thing:

(1) you want a SSR controlled 240V receptacle for your heater element
(2) you want a 120V receptacle for your pump that is just ON when the main switch is on.

If that is correct and, then your current wiring needs to be changed. As drawn and wired, your pump is only going to come on when the SSR is enabled. And, you have that path through the element to the pump than you really don't want to have.

You want to move the fused line to your pump receptacle over to the "Phase Y" main line and get it away from the SSR.

HOWEVER, in the future, you would like the ability to have the 120V outlet controlled by the SSR.

If that's also true, then what you could do is have a SPDT switch (ON-OFF-ON or ON-ON) to control the behavior of the 120V receptacle.

In one position, the switch will pass "Phase Y" to the hot side of the 120V receptacle. This will be your setting when using the outlet for a 120V pump while your 240V outlet is a PID controlled outlet.

In the other position, the switch will pass the SSR controlled "Phase X" to the hot side of the 120V receptacle. This will be your setting when you want to use the 120V outlet as a PID controlled outlet. YOU WILL NEED TO UNPLUG ANYTHING FROM THE 240V OUTLET IN THIS MODE.

 

[BetterSense]

Right. For the time being i just settled on a non-SSR 120V receptacle. I don't have any high-current switches right now.