Inexpensive water temp alarm.

[Simi 60]

I have an engine guard on my primary engine and it has paid for itself already going off well in advance of the engine overheating by simply clamping the sensor probe after the mixing elbow.
Something reduced water flow - exhaust water temp increased and alarm activated.
Its not pretty, its surface mounted but it works.
https://engineguard.com.au


Pretty simple device so that had me looking for a diy ish alternative for the genset and something i could panel mount and I found this

AutoSpeed - $25 Temperature Controller and Display!

Bought it, a piezo buzzer and a longer probe to reach down a deck level and wired it up as per directions but temp adjusted back to 47c.
Works a treat.

[redsky49]

Excellent. Thanks.

[travellerw]

We have a similar solution on our boat, but a little different.

Ours uses just 2 components. A standard thermal switch (normally open) and a buzzer. The thermal switch is strapped to the exhaust elbow. The buzzer is wired through the thermal switch.

I just threw these links together, but if you search, you can get the components for less than $8 (for both). Damn cheap insurance.

Here is a link to the parts.

https://www.ebay.com/itm/2Pcs-10A-25...-/202303194584

https://www.amazon.com/SooKoo-HYD-42...3CXJ4G5SS59DC5

[a64pilot]

People use those things for refrigerator thermostats, controlling fans, all sorts of reasons, they can be had pretty cheap, here is an Amazon listing, I’m sure Ebay is cheaper
https://www.amazon.com/s/ref=nb_sb_n...ywords=stc1000

[AlanR]

The 110/220 volts AC supply to run these is a problem on my boat. What do you use?

Alan

[capt jgw]

They're also available in 12 volt DC. I have one of those running the fridge unit in my boat. I also have a 120 volt AC unit running my home brew fermenter at home. They work great. Never thought of using one as an engine alarm. Great idea.

[a64pilot]

They come in 12 and 24 V versions too. These are 12v
https://www.amazon.com/s/ref=nb_sb_s...3Astc-1000+12v

[FionaJC]

I used a cylinder thermostat for years. When we changed the engine a couple of years ago I bought two exactly like these from eBay. I keep one as a spare. The new mix elbow had a thread for a sensor so I drilled a bolt epoxied the sensor in and bolted it in.

[qwert]

I have a similar arrangement. In mine I made a small hole in the steamhose about a foot after the elbow where the water comes in. I inserted a small thermocouple which is connected to a digital display and sound alarm. If the water is turned off it gives loads of warning before the engine block even starts to warm up. The thing I found most interesting is that the highest temp I have seen in the exhaust in the two years since I installed it is only 62C (apart from when testing with water off).

[trikola]

For different applications of not-so-critical kind I have started to use IKEA: https://www.ikea.com/us/en/catalog/products/80100406/