Heater issue

[xcaret]

Might not be the proper way to calibrate but I used it in the past; I purchased an Exogen Temporal Thermometer and I was ok with it.

 

[rygh]

The SSR inside of the heater is submerged in the water so the heat is not an issue. For external controllers it might be a problem. And this is another point to say external controller MAY add another point of failure instead of increase of reliability.

But that implies it is IN the heater body, thus next to the heating element.
If done right, and SSR is thermally connected to the heater body, and thus water cooled, it would be fine as you say.
But if not, it could be even worse.
It all comes down to quality and design, which is a bit unknown.

 

[sfsuphysics]

All this talk about adding points of failure as if that is worse. If you have a heater and controller, yes there are 2 points of failure, but both points of failure need to occur for a "critical" problem to occur, unless it fails off but it seems that failing on is the largest issue.