The element will struggle if there are burnt protein/sugars on the bottom, which is why you may see the unit not hit the target. See here for more information.
There are two main reasons;
- Low amount of water in the base of the boiler causing scorching due to, wort with too high a sugar content, collecting on the element. Ensure your recipe creator uses the recoverable dead space for the Grainfather units.
- Grain matter settling on the element and burning on the element. Ensure your grain crush has a good proportion of course and fine crushes. Also, consider using the overflow filter to help stop grain matter getting in to the bottom the boiler.