What witchery is this?
I think I'm pretty happy with my pistons, really.
It's basically this, probably most of you know how to do it:
________________________Boiler controler______
|Piston|Brick|Redstone block|___________|brick|Piston|
It works like this: Tank empty, redstone signal activates a piston that push a redstone block under the boiler control, activating it. When it starts to fill, the piston will retract, but the block stays where it is. Until the Boiler hatch gets full, and sends a signal to another piston, that push the Redstone block back to it's original position, deactivating the boiler. The brick is there only to avoid direct contact with the piston, keeping it active. It's simple, and don't blows my head off
It stays under the boiler too, so It's hidden all the time, not so ugly.
But I'll read this link, maybe is easier than appears...
---Edit----
I see that you are using a LHE, so Boiler input is also a concern. ATM, I'm using regular boiler and charcoal isn't a problem, so I dont need to check for it. Maybe later I'll do a more complex system, probably using a hidden room underground and attach inputs and outputs to wireless RS transmiters. Like a program fuction