No, it does not work with lava. You monster.
The Aqueous Accumulator is one of the Machines added by Thermal Expansion. It generates Water by extracting it from the Machine's surroundings. This is done without actually affecting blocks in the world. The Aqueous Accumulator is one of the few Machines that doesn't use Redstone Flux.
The Aqueous Accumulator actively generates Water if either of the following conditions are met:
When the Aqueous Accumulator is actively generating Water, it adds some Water to its internal tank every 1.6 seconds (32 ticks). By default, 800 mB of Water is produced every time this happens, but this amount can be increased by installing Processing Speed Augments.
If enabled in the config, the Aqueous Accumulator also passively generates Water if it cannot actively generate it. By default, the Machine then adds 32 mB of Water to its internal tank per operation. This amount can also be increased using the same Augments.
The Aqueous Accumulator does not have any inputs; the sides of the Machine can only output the Water that is generated by the Machine. These sides can be identified by their orange openings. By default, all sides but the front side are set to output Water.
The amount of Water the Aqueous Accumulator generates can be changed in the config. The values in the config, however, are in mB per tick; not mB per operation. Every operation takes 32 ticks, so the amount of Water generated per operation can be calculated by multiplying the values in the config by 32.
The Accumulator also cannot be configured to generate more than 1000 mB per tick.