Another E-brewery design 1 PID, 2 Elements, 4 SSR's

[Lucky_Chicken]

I had one fail on me after a year (appx 20 batches I guess). I chalked it up to the fact that my control panel had NO ventilation and the SSR got pretty hot while in use.

When I replaced the SSR, I cut a couple of holes in the box and mounted two small fans in it to blow air across the SSR heatsinks. time will tell if this helped.

related question... if your SSR fails how to you finish the brew day?

 

[Walker]

related question... if your SSR fails how to you finish the brew day?

In that particular case, I didn't finish. I really never got started. I discovered it was bad while heating up water at the start of the day. I had things set to heat water to 165 or something and when I looked at it after milling grain, it was up at 185 and climbing.

I had a friend in the process of slowly building his system, so I bummed an SSR off him the next day and brewed.

When I ordered my replacement SSR, I bought several of them. If it ever happens to me again, I can shut the system down and swap out the SSR (about a 5 minute job, max).

 

[kal]

Amber Pilot Lamp | Princess Auto

these were the pilot lights i was planning on using elsewhere in the system.

they are neon as well.

IMHO they are junk (brittle/fall apart). I looked at the princess auto switches and lights back when I first designed my setup.

If an SSR fails with the contacts closed. I will have an audible alarm wired as well as a pilot light to alert me that there is voltage present, at the heater when there shouldnt be.

So you're going to watch these pilots lights 100% of the time you're working on something that you consider dangerous and then quickly pull your hands out if one of the lights all of a sudden turns on?

SSRs don't just fail by not turning on or off when you go to turn them on or off, one could all of a sudden turn on or off.

Having an audible alarm to let you know when one SSR fails without the alarm being on whenever the element's firing normally requires some extra circuitry. You basically have to recreate this sort of logic:

If (PID is not firing) AND (voltage is present at element) THEN Turn on audible alarm

To do this would probably require an extra relay or something to latch.

You can't just wire the audible alarm like the pilot lights as otherwise it would constantly cycle on and off as you used the system. Very annoying.

Bottom line, im not designing this system for sale, im designing it for my own use.

Yup. You can do whatever you want.

The only reason I'm bringing up stuff is because you seem to think that the extra steps you're taking are going to make your system safer and I don't agree so I'm cautioning you to be careful.

I'd feel better if you said "I'm not putting anything extra in there and understand the dangers and will be careful".

A lot of people wire up elements directly with one SSR driven off a PID such that one side of the element is aways live. That's fine as long as they understand what they've done and use it accordingly.

Kal

 

[thargrav]

I wonder how many are attempting a build without a heatsink?