How do I switch to Fluid Reactor/Heating mode?

I've looked a long time for a clear explanation, I still don't quite understand. I've made a reactor with all the extra chambers, I've wrapped all those in pressure vessels except for a redstone reactor port (which I"m giving a singal, a reactor fluid port, and a reactor access hatch (each of which is connected to a chamber. But it stills says it's in EU mode, and the fulid port won't put out any coolant. What else do I need to do?

I didn't previously have an entire 5x5 cube. Now I've ....hoping that I understood you, made sure that the reactor pressure vessels comprise a perfect 5x5 cube once wrapped around the original reactor chambers, however attaching a hatch to that creates a hatch that I can't open and interact with. Is this all laid out some where? I've been trying to piece it together with a lot of searches, no luck so far.

oh! Are you saying that I should place a vessel at the end of each "protruding" part of the chamber, and that nothing at all is allowed to exist in the space between this hollow cube and the reactor chambers? And where exactly do I place the red stone port, the fluid port and the access hatch?

wonderful, thanks very much.

Another quick question: Do RZH and LZH cooling work to produce heated coolant for your 5x5 system? Or is that considered the wrong kind of cooling?

Edit: Looks like it doesn't. Which means no 5x5 will ever approach this crazy monstrosity:
http://www.talonfiremage.pwp.b…kof2ojdg63f066fmkmgnfkf0g

Still wanna build one though, but I think it's kind of disappointing that the cool/advanced heating mode can never reach the heights of EU mode because of this (unless I've missed something.)

Quote from Requia

LZH and RZH cooling reactors are useless in the real world. Where are you gonna get 150 stacks of lapis per cycle?

I'm really glad to hear that. It makes 5x5ing more fun. Here's my first completed survival mode 5x5, your thoughts?

(survival) My First 5x5: BioGas, ~900EU/T, self feeding. 10 Uranium Rods Stable