+1 on aquarium sealant. A lot of caulks are mildew resistant and that stuff is probably poisonous. I looked at a GE Silicone II MSDS a few years back and decided it wasn't good for contact with food.
Actually, look around for some better 555 circuits. That one doesn't seem well suited for this purpose. I would expect you want to drive the ssr with pin 3.
Most SSRs will only turn on at the start of a half-cycle, so pulsing it with such a high frequency will not be useful. Keep the frequency around 1 Hz instead.
Dan
Well how long does it need to be to reach through the tee? Not everyone uses a sight glass. Having too long of a probe means it either interferes with the IC on the inside (Yes I saw that stated above) or gets knocked by someone's arm on the outside.
Having too short of one means you can't...
Exactly. Why would it need to stick in more than an inch or two?
(Um...I'd rephrase that if I could think of a better way to put it.)
Anyway we're looking at thermocouples because the one we have now works for pretty much....no one. 1/4" NPT with 2" immersion depth seems to be the winner...
Keep the water temperature below 180 in those plastic coolers and you should be fine. The end of the element by the fitting is not very much hotter than the water itself.
Unless you have a jig you can't get it round enough with a dremel. And you can't drill a pilot hole for the larger one. The OD of the threads on the element (at least the one in front of me) is 1.285" so even 1 1/4 won't quite do but it might be a reasonable start.
The machine shop that does...
Assuming you shield the wires from the flame are you sure you have 240 available? That's not terribly common with 3-phase. If you have 208 that works but your 5500 watts becomes 4100 watts. If you have 277 you'll want to choose an appropriate element.
Grab a meter and set it to the highest ohms setting. If it doesn't read overrange between hot and ground, you need to start over.
EDIT: By "Ground" I meant the part of the heating element that touches the water and keg! You don't want current going there.
You're going to want a separate ground connection to the top cover. The hinges can't be counted on for safety reasons. Being able to hinge it open means it's "field serviceable" which puts a whole new set of requirements on it. A trip to the library to grab 60950-1 could be worth the while...
Well lookie here! Someone (by accident I hope) posted UL 499. Although this is for appliances that HEAT liquid, you can still get some ideas. Like section 11.3 saying even if liquid leaks, it better not be able to get to live parts.
There is a newer version of this standard than this, and...
Yea one guy said the same thing. Except I'm proposing you don't care about the positive and negative polarities you just have to filter the square wave from the output. There are tons of ways to do it.
470K will not trip a GFCI and the ground leakage it adds is within acceptable limits unless...
It's a prototype, cut him some slack. Take a look at UL 916 or 60950-1. I don't know if either one covers liquid in the same chassis as wiring but they might. There may be a more appropriate safety standard for those. You can buy the docs for a few hundred bucks but if you're lucky your library...