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  1. #1

    How to add water temp alarms?

    I currently donít have anything that beeps if the water temp shots up due to a possible impeller failure. What are the different ways I can install an alarm system against over heating?
    Akin Tosyali
    Hatteras 41 -Barbaros


    Barbaros, Hatteras 41' Before and after restoration

  2. #2

    Re: How to add water temp alarms?

    Aqualarm has temp alarms you can install on your exhausts. They will trigger sooner than coolant alarms
    Miami, FL
    1970 53 MY #325 Cummins 6CTAs
    2014 26' gaff rigged sloop
    2007 Sandbarhopper 13
    12' Westphal Cat boat

  3. #3

    Re: How to add water temp alarms?

    As Pascal suggested, Aqua Alarm also makes flow alarms that you put in your salt water line to indicate a loss of raw water flow.
    Mahalo V
    1974 53 Motoryacht
    Hull Number 406
    San Diego, Ca. Ready 32 Nordic Tug, Brunswick Ga.

  4. #4

    Re: How to add water temp alarms?

    Hi Akin,

    Those are great suggestions.

    To round it out, I offer a simple approach:

    A conventional temperature warning light switch (not "gauge sender") for automotive applications has either a single connection or two (for the old school units).

    They work by grounding the connector under higher temperatures. The two connection version just has a separate ground. You just plumb it in with a tee somewhere near your existing sender for the Hatteras gauge.

    If you get something called a Sonalert, and put the + to positive voltage, and run the - to this switch then it will buzz if the temperature exceeds the setpoint, which is usually just above 200F.

    But honestly, $45 will get you a lot more functionality:


  5. #5

    Re: How to add water temp alarms?

    I made my own overheat alarm as I just didn't trust my old monitoring system. I installed normally closed water temperature switches on each engine using vacant plugs in the coolant side of the engine. The wire starts as grounded to the engine and goes in series through each switch and up to the bridge. In the bridge there is a relay that is grounded via this wire. I have a 12 volt switched supply wire which I turn on when I get ready to crank. This energizes the relay and holds the circuit open that powers a connected horn. If the ground is broken by an overheat or a defect in the wiring to the bridge the horn will sound. The horn is actually a Cole-Hersee red light with a buzzer in the rear. I also have a green pilot light that tells me when the system is on. It was real simple to make and not very costly. The hardest part was fishing the wire from engine room to bridge. Also I used switches with a low rating. I think they were around 200 or 205 degrees F.

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