I used a boiler to heat milk (the one with the coil inside) after a few seconds it started smelling bad like burnt food, i immediately drained the milk inside i noticed the coil was burnt it had this cracked up texture .. why did this happen? i had no idea it was wrong to use other liquid products with this heater besides water :(
What happened is that the milk solids congealed on the coil and insulated it so that it overheated. If the cracked-up material does not clean off or if any part of the coil is now exposed, the boiler is toast and must be discarded.
its ok to use milk in a water heater, Its probably just old age or unlikely somehow it got used it once with nothing in. I think you should be able to get a replacement element if its not too old and fitting it will be straightforward ( with new gasket seal ) for an experienced diy person.
