Is there any way to add a float valve to a Big Mouth vent?

find out how water got that high?

how is that a safety measure?

Filling the system with water is the problem.
if a breaker trips you don’t install a larger breaker you find out why.
apparently you know the cause so correct that.

@ethicalpaul said the floats don't actually float.

If that's the case...

Yeah the “float” in the #1 definitely sinks like a stone. I haven’t opened a #2 to test it but if someone sends me a broke one I will.

Gorton almost never calls it a float (but I think I caught them saying at one place deep in their web site).

so if someone **** off the emergency switch you’ll bypass it?

My bet is the 'Float' in a Gorton 2 will NOT close the valve, not enough trapped air for the weight involved.

Maybe a redundant water feeder?

I'd still go with the Gorton.

you could pipe the vent outlet to someplace more convenient. vinyl tubing would probably be ok, just make sur it is sloped so it doesn't trap any water that does burp out of it

you could go up if you dripped it to a wet return but that is starting to get complicated. you could move the vent itself but the pipe to the vent would have to be able to drain back to the main.

I suspect the sensor is behind the LWCO unit in the pipe, like it typically is. The 'High Water Cut Off' in the video is physically above the boiler, above the header, where water should not be.

You could also use an additional Pressuretrol (normal location) with a SPDT switch. Water head pressure, 2.31 feet of vertical water height, you get 1 PSI of pressure or 0.43 PDI per foot. Use the N.O. section of the switch so when the pressure increases it closes the switch and closes a Normally Open zone valve.

You could get creative with the existing Pressuretrol wiring so on a pressure rise that shuts off the burner it also removes the power to a Normally Closed Zone Valve that is wire up so it only opens during a low water event. Basically redundant water valves with independent control, one low water, the other pressure too high (water height).

i don't think you want to shut off the water feed based on pressure. if the controls run away you want it to keep feeding water to absorb the energy from the burner. it is kind of where the relief valve becomes the last ditch effort safety. if the relief valve is blowing off and the water feeder is trying to replace the low water level it is likely to keep a burner with a stuck gas valve or stuck relay or other stuck safety in control enough to keep it from burning the building down

it could be a couple hours if the boiler is voersized as most are.

@Danny Scully, you seemed disappointed that folks at the time of the original post (2019) and other later posts did not seem very interested in the High Water Cut Off.

Personally I like the idea. I think where it falls short, is if you are not going to market it as a kit, explain it in more detail (and maybe I missed it). If folks better understood how to implement it, it may get more interest.

Why you chose that LWCO.

Why you chose that Zone valve.

How you wired the LWCO to the zone valve, is it an automatons system or does it interlock with the boiler's other wiring.

More details on how it works. Why you chose that height in the system instead of lower. If folks are confused and can't build it they are not going to use it, even if it is a great idea.

Some folks may get discouraged if they have to figure it out for themselves.

From another post;

" Just to be clear, it looks like you're using a regular low-water cutoff
and a Taco "Zone Sentry" valve - the "normally open" type. So if the low
water cutoff actually turns on - i.e. there *IS* water - then the Taco
valve shuts off. And it looks like you rigged that up to the same set
pipes on the side of the boiler where you've got the pressure gauge -
yes? Not familiar enough with the boiler internals to know, but doesn't
steam come out of the hose when the boiler's heating? "