Float switch in boil kettle?

I was thinking about putting a stainless float switch in the HLT to protect the heating element. Would those work/survive the boil kettle too? Wondering if the turbulence could be a factor. Anybody done this?

I've go one in mine and so far so good, but only 1 batch, brewing next week so I'll update after that if there is any change. I also mounted a din rail mount 12v transformer on the inside of my control panel to power the switch. I have one in my HLT and one in my BK, both are wired to 12v red buzzers to go off when my water level is about 2 gallons from exposing the element.

amurphyz said:

I've go one in mine and so far so good, but only 1 batch, brewing next week so I'll update after that if there is any change. I also mounted a din rail mount 12v transformer on the inside of my control panel to power the switch. I have one in my HLT and one in my BK, both are wired to 12v red buzzers to go off when my water level is about 2 gallons from exposing the element.

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Thanks. I was trying to avoid the "safe start interlock", ala The Electric Brewery by using these switches to power off heater relays. As a former engineer, I feel better protecting against dry run/burnout all the time instead of just on startup.

Since I was only half way through building mine and decided I was going to build another one that made things a little cleaner inside, I'll have to steal your idea for my next build, thank you!

amurphyz said:

Since I was only half way through building mine and decided I was going to build another one that made things a little cleaner inside, I'll have to steal your idea for my next build, thank you!

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Sure! We all use ideas wherever we find them! I'm thankful for all the ideas found here.

Seems like it's taking me forever to get my own design together, as I keep finding or figuring out methods that help simplify, improve, or reduce cost. In retrospect these delays almost always pay off in the end with a better, optimized design, but it's so tempting to just start assembling......

I have one of these stainless float switched in my HLT and BK, So far I have had no issues with them.

I put a female 1/4 headphone jack into my control panel that interups the signal to my SSR, and wired a male adapter to the switch.


The switch took about 2 weeks to get here from china.

Bsquared said:

I have one of these stainless float switched in my HLT and BK, So far I have had no issues with them.

I put a female 1/4 headphone jack into my control panel that interups the signal to my SSR, and wired a male adapter to the switch.


The switch took about 2 weeks to get here from china.

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Thanks. I was looking at the straight ones(same maker) that are vertical install, but the rod length then determines the active position. Think this one is better as it doesn't dictate how high to install the burn element and the problems inherent with a bottom install. Thanks for the link!

I don't have anything in place and this weekend should be my first run on the new electric setup, but I'm very interested in some sort of safeguard to prevent dry-firing of an element.

Not meaning to hi-jack the thread, but this might be of interest to those reading it:

APress book "Practical Arduino: Cool Projects for Open Source" had a chapter titled:
"Water Tank Depth Sensor".

It might be very applicable to what most of us are trying to accomplish. The same book has a couple of other interesting chapters:
"Online Thermometer" and "Water Flow Gauge".

For those of you that have done this, do you have it wired such that the element is totally dependent on the float switch? Or do you have the float wired into a selector switch that allows you to give element control to the float, or bypass yourself to control element power on/off?

I have one of the same ebay switches sitting in my "pile of things-to-be", so any tid-bits on how you incorporated it into the world of wiring would be appreciated!

BrothOfVigor said:

For those of you that have done this, do you have it wired such that the element is totally dependent on the float switch? Or do you have the float wired into a selector switch that allows you to give element control to the float, or bypass yourself to control element power on/off?

I have one of the same ebay switches sitting in my "pile of things-to-be", so any tid-bits on how you incorporated it into the world of wiring would be appreciated!

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I haven't done it yet, but my plan is to put it between the PID and the SSR, without any way to defeat. If putting on the far side of the SSR, one would need a contactor (which most 240V systems have anyway).

RichBenn said:

my plan is to put it between the PID and the SSR, without any way to defeat.

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Yeah, this definitely seems like the most straight forward approach. I use hop bags though and am worried about a bag snagging onto the switch and tricking the system. I suppose if you had some kind of buzzer or light indicator to let you know the float switch was triggered you could remedy it pretty easily.

I still like the idea of being able to bypass the float when it is time to boil, since I know I wont be running into chances to dry fire at that point. But I suppose that does leave me the chance to leave the switch in bypass mode on the next system start up...

BrothOfVigor said:

Yeah, this definitely seems like the most straight forward approach. I use hop bags though and am worried about a bag snagging onto the switch and tricking the system. I suppose if you had some kind of buzzer or light indicator to let you know the float switch was triggered you could remedy it pretty easily.

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Hmmm, thanks for mentioning that. I use one of those hop spiders right now, so I'll have to check the depth and see where it falls, worst case. Hopefully, it'll be away from both the elements and the switch.

Electric heating sure has it's own set of challenges....