Low water/No water alarm for HLT and BOIL KETTLE

[Wheelspin]

After (stupidly) flicking on my boil kettle (which was dry) the two 4500 kW elements quickly popped on quite spectacular fashion.

Does anyone know of an easy to fit low or no water alarm I can put into my HERMS.

Should be able to stay in kettle even when boiling and only activate when I switch on the elements.

Any help appreciated.

 

[Wizard_of_Frobozz]

How about this: https://www.amazon.com/dp/B01LYCTVT1/?tag=skimlinks_replacement-20

Need to pay attention when wiring it up; say it's DC only so maybe in series with the control signal going to your heater SSR?

 

[postalbunny]

An alternative here is to wire your SSR signal through these float switches; it's lower voltage. Eg, the signal from your PID goes through this switch toward the SSR that fires your element. That way a low water level will make it impossible for the element to fire until the float raises.

Doing something similar with a flow switch and RIMs tube... if pump loses prime or gets stuck then the flow switch kills the signal between the PID and SSR.

 

[Wheelspin]

Thanks for those commnets.

Is there not some type of probe that I can put thru the side of the kettle wall that activates an alarm when the element switch is turned on and there tank is dry ?

Float switches are OK but i don't always want to fill my vessel when I switch the elements on IE When i just want to heat some water for flushing the HERMS.

 

[BrunDog]

You mean you want non-mechanical? There are optical ones that can work well. I don’t recall offhand if they can handle boil temps.

 

[postalbunny]

You could just wire teh float switch to an alarm... that would work fine.

 

[augiedoggy]

An alternative here is to wire your SSR signal through these float switches; it's lower voltage. Eg, the signal from your PID goes through this switch toward the SSR that fires your element. That way a low water level will make it impossible for the element to fire until the float raises.

Doing something similar with a flow switch and RIMs tube... if pump loses prime or gets stuck then the flow switch kills the signal between the PID and SSR.

this is what I do on both my HLT and rims.

Also ULWD elements which are ideally the best for the BK shouldnt be "popping" that quickly... are these ripples or regular LWD straight elements?

 

[augiedoggy]

Thanks for those commnets.

Is there not some type of probe that I can put thru the side of the kettle wall that activates an alarm when the element switch is turned on and there tank is dry ?

Float switches are OK but i don't always want to fill my vessel when I switch the elements on IE When i just want to heat some water for flushing the HERMS.

The idea is you mount the float switch at the height of the element so it only allows the element to fire if the water level is high enough to cover the element. thats what I did.

 

[RocketBrewer]

The idea is you mount the float switch at the height of the element so it only allows the element to fire if the water level is high enough to cover the element. thats what I did.

This is what I did in my HLT (havn't got around to doing my BK) and it works great. I used one like this through the side of the pot to interupt the control signal from the PID to the SSR.

 

[augiedoggy]

This is what I did in my HLT (havn't got around to doing my BK) and it works great. I used one like this through the side of the pot to interupt the control signal from the PID to the SSR.

I use the same one.