What does 'Minimum Water Level' mean on a heater? I water level must be lower or higher?

Discussion in 'Equipment' started by Vincerama2, Jun 12, 2013.

  1. Vincerama2

    Vincerama2 Evil Overlord

    Maybe I've asked this before, I don't remember.

    It's time for a new heater. But I'm wondering. Most of mine have a line that says "minimum water level" which is weird since it's something you put into water, not something that contains water.

    So does that mean the heater must be submerged AT LEAST TO the line, and maybe even submerged more ... so that it doesn't overheat if too much glass is exposed to air.


    does it mean not to submerge the heater any more than that line, because you might short out the electrical elements.

    My heater is currently in the sump and the line is basically just at that line because ... I don't know if I need to put it in the water MORE or LESS.

    What say you?

  2. rygh

    rygh Supporting Member

    Put heater in the water at least that far. Yes, for thermal issues.
    Generally best not to submerge the temp adjustment knob at the top.
    "Supposed" to be sealed but ...

    What I look for first is a heater where the electronics are separate from the heating element.
    Being in the electronics industry, I see so many times how heat really reduces the lifetime of components.
    Plus the electronics are also well away from the water.
    Redundant controllers are even better, but expensive.
  3. Help my heater doesn't have a minimum water line!

    Silliness aside, +1 to what Mark wrote.

    Unless the heater is specifically identified as a non-submersible heater (not many these days, but I do have one of the non-submersible types that are meant to hang off the edge of the tank), I would interpret the water level as "always submerge past this line." Typically that is near where the thermostat is located.

    If you still have any doubts, post a picture or manfacturer/model of the heater.

    BAYMAC Guest

    Min = not below
    Max = not above

    Heaters will have both terms on them.

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