Well, true to Russia’s characterization, it’s immensely
messed up. A pechka is a Russian stove…

What I get from it is that since Russia is always cold and
hates it, his heart has frozen over. This isn’t all that crazy since we
know that he’s persistently attacked by General Winter every year, and naively
longs for summer weather.

Perhaps he wants his heart to defrost so that he can start
feeling again rather than being emotionally numb and unaware.