What is proper function of a heater?

[Dom]

Yes... I know proper function is to warm the water. But my question goes a bit deeper than that.

I use a temperature controller and keep my tank at 25 Celsius (77 Fahrenheit).

I noticed about 2 days ago that the temperature dropped to 21Celsius. The heater appeared to be functioning as the light was coming on and off. But clearly, it wasn't heating the tank.

I replaced it with an exact duplicate. The light came on and the temperature is slowly coming back up.

But what I have noticed is that the heater will turn off (light will go out) before the tank has reached its target temperature.

Is it normal function for a heater to turn itself off before reaching target temperature? It seems as if there may be a safety feature that limits how long a heater remains on.

Thanks

 

[theMeat]

Don’t think so. Where is heater and where is probe for controller?

 

[Dom]

Don’t think so. Where is heater and where is probe for controller?

The controller probe is in the tank and the heater is in the return chamber of the sump.

 

[nereefpat]

The temperature setting on heaters aren't always spot on. Try turning the setting up a couple degrees.

 

[Dburr1014]

If the probe is down stream of the heater, is it possible the water is heated enough that the probe senses it?
A heater won't shut off until the internal probe reaches temperature. It's dumb, on or off. It doesn't know what temp the water is, only to shut off when it reaches the temp you set it to. But as the water heats the other probe might feel that heated water as the temp you set.
Have you tried to move the probe to a different location?

 

[theMeat]

The temperature setting on heaters aren't always spot on. Try turning the setting up a couple degrees.

This. Keep the temp on heater itself a couple of degrees higher that the controller. Definitely do not trust the adjustment numbers on the heater. They’re always wrong. Use a bucket and a trusted thermometer to dial it in a couple of degrees higher than the controller

 

[Dom]

The temperature setting on heaters aren't always spot on. Try turning the setting up a couple degrees.

I run the heater on max. I wonder if it is a function of the controller? The controller may be designed in a way that prevents the heat from being on more than some fixed number of minutes.

I can see this as a safety feature. But I'm not sure.

 

[Dom]

If the probe is down stream of the heater, is it possible the water is heated enough that the probe senses it?
A heater won't shut off until the internal probe reaches temperature. It's dumb, on or off. It doesn't know what temp the water is, only to shut off when it reaches the temp you set it to. But as the water heats the other probe might feel that heated water as the temp you set.
Have you tried to move the probe to a different location?

Can't like this post enough!

Initially, the heater was in the refugium (I know... I know...). And the probe was in the return chamber (downstream from the heater).

Now I moved the probe upstream from the heater.

 

[Unitylover]

I think i know why, heaters are usally coils. The coil takes time to cool down after the heater stops heating it