Question about heaters.

[chrisely24]

Background... 60G glass tank in a large living room that stays around 65-70 degrees this winter with temps outside ranging from 30's to 70's.
300W Eheim heater.

My question is if I have the heater set at 78 degrees and the tank is reading 72 degrees shouldn't the heater stay on constantly until it reaches 78 degrees?
I know that maybe the room is too cold and the heater may not be able to achieve 78 degrees but i would think it would stay on constantly and keep trying to reach the temp. I.E... Why does it even shut off if it is not at the set temp?

I have had 2 other heaters before I bought the Eheim and both of them did the same thing.

 

[snakeblitz33]

Is your heater set on exactly the temp you want?

How do you know it's turning off?

What device are you using to take the temp?

 

[bang guy]

Is there enough waterflow around the heater to remove the warmed water from around it?

 

[chrisely24]

Snake, yes I calibrated the heater per instructions when I got it.
I know it's turning on and off by the built in light.
i have a digital thermometer with a probe that is on the opposite side of the tank from the heater and I have also used a digital probe thermometer that reads the same within half a degree.


Bang, I have the heater positioned right next to my sump output and near a powerhead.

 

[chrisely24]

I was just thinking that the room was too cold for the heater to keep up with. My house thermostat will switch to emergency heat if the room temp is lower than 8 degrees or so of the temp i want it to go to then it will switch to regular heat.

Even if the tank heater is struggling to keep up I would assume that it would stay on constantly, am I right?

 

[bang guy]

Yep

 

[jay0705]

Generally they wont run all the time. They will just not be off long. But a 300w heater for your size tank should have np getting it to 78

 

[jay0705]

I have a 300 in my 75. And I live in ny , have u seen our temps lol. It holds steady at 76. But it is on alot. But not constantly