Mike
The Rio 1100 that I have just gets warm to the touch. I really doubt that this one in my system is adding much more than say 5-10W to my systems overal heat. As you can see from my pics the CPU is putting out about 100W and the TEC chipset waterblock is puting out around 50W or so.
I also have that pump mounted in the front with a case fan blowing air on it (not intensionaly butit worked out well)
4 of the RIOs (or any pump for that matter) sitting in a bucket of standing water for hours would heat upo the water no matter what
as you probably already know. Keep in mind that your 1400 Rios put out the equivalent of 260-275GPH @ 3 feet head so they do quite a lot for just that little amount of heat.
Correction: the 1400 puts out 290GPH @ 3' head and 420GPH @ 0' head. Also yours uses 27W of power (mines 22W) however I doubt that 1/2 of that is going straight to heat. I just checked the spec. chart that I got with my RIO on all this info.
In short, IMHO that they run relatively cool for what you get out of them.
Hope that this answers your questions.
Anything else?
Good luck and let me know how it works out for you.
BTW: yes the outake on the RIO 1100/1400 will hold the 3/8"NPT and the intake will have to be taped for (i think) 1/2"NPT. I would have taped mine but didnt have the tools available
