Hello !
I've a problem using Build Craft's pipes : my liquid heat exchanger worked fine (with the liquid ejector update), but now it starts to be weird... Look at this screenshot, you'll understand quite well... 
I'm in MC 1.7.10
Thanks in advance for your help.
actually you don't need pipes. you can set your liquid heat exchanger directly on the reaktor fluid port.
but you can also use pipes. if you wanna do that, do not use liquid ejector upgrades in you liquid heat exchanger. pump it out with emerald pipes and a coolant cell as a filter (hot or cold). for pumping you can use autarcic pulsar gates or engines. but pipes are not recommended in my opinion cause they have a travel time. if you set the liquid heat exchanger directly to the port, they can exchange liquid to each other directly and without time loss.
You could also try setting a direction to the fluid ejector.
How can I do that please ? 
By right-clicking the upgrade on a side of a block (top for top side etc)
