Improving the efficiency of a hydraulic pellet stove (EcoTherm Thermorossi H2O)

[Did67]

I do not remember the details, but yes, storage of solvents in the boiler room, it was enough, it seems to me!

[Christophe]

Ah a "nano" air pollution could therefore lead to these results?

Ok that's fine with me ...

It's homeopathic pollution

[Ahmed]

I remember having observed such a coloration on the cast iron bars (forming a grid) of the inverted hearth of a wood-fired boiler. It is somewhat the same case, since your "springs" (in reality spirals) are subjected to high temperatures (in the presence of oxygen), without the possibility of heat exchange towards a cold source.

[Philippe Schutt]

At this place we have a strong heat, I think we arrive at dark red, and as the combustion is in excess of oxygen the metal oxide. These springs are sometimes made of stainless steel.
What is your T ° of smoke before and after your assembly?