Reflow Oven – sorting out the 240V side…

Here’s a tear-down of the reflow oven. I was hoping to finish this tonight, but as you’ll see, it seems better to pick up a few bits I’m missing and do a far better job than the one I was planning. It is mains after all so no harm in doing it right rather than cocking it up.

Getting the oven apart wasn’t too bad once I had the correct security bits (which did turn up on Tuesday):

Side view

Side view

The side view show the power going in with red being the live wire.

Connection to timer switch and power setting

Connection to timer switch and power setting

The timer switch (on the right) has the live lead going to the bottom of it. The “output” goes to one side of the indicator bulb and back out to the ends of the heating elements on the right-hand side of the unit. The other side of the bulb connects to one side of the power connector and the incoming Neutral feed.

Removing the timer

Removing the timer

The timer knob pulls off to reveal the screws that hold it in place.

Timer

Timer

The real job here then is to replace the timer with a solid state relay:

Timer replacement

Timer replacement

Live + 2 x "Output" wires

Live + 2 x “Output” wires

The SSR needs to connect to the live as “input” and the other two wires (heating elements + bulb) as “output”. I was originally going to use a bit of Veroboard but I can’t get comfortable with that. It’s going to be a bit of a bodge job if I solder the wires and the SSR onto some crummy bit of board and then stuff it in the base of the unit somewhere.

I started looking at the side of the unit where all the power comes in. It can’t be any hotter out there and there’s much more room to place the SSR where I want. I’ll pick up some 5A connector strip and a piece of whatever you call that heat resistant wire then I can easily pull out the live wire and safely join those other two to a new wire going back to the inside of the plastic side panel.

Easier out here...

Easier out here…

It looks like I’ll be able to stick the SSR on the side out of the way (more hot glue then 🙂 ) where I would imagine it would stay fairly cool being low down.

So, not finished yet but I think I have a plan…

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