The heat generator will burn through a coal in less than a second, producing only 480 RF (not enough to pulverize 1 item)

Increasing the output ten-fold in the config makes it generate the expected amount of power, but it still does so absurdly quickly, other generators seem unaffected.

I think this was intended. Heat generators, being the first and cheapest available, are supposed to be highly inefficient when burning fuel. They're best used in passive mode.

I don't think THAT inefficient would make much sense, 480 from a chunk of coal... You might as well remove the active mode completely, who's gonna put a STACK of coal in just to pulverize one item? For reference, a SAPLING in a Buildcraft stirling engine will produce 1000 RF, and that engine is made with cobblestone and a piston... So a chunk of coal in this is intended to produce less than half the energy of a sapling in another mod's solid fuel generator? I don't buy it...

Fixed.