V12|V12:
I recently pulled out a PWM fan controller that I have and replaced the power MOSFET with one that would handle 4 amps (48 watts). With this I could test my Comair Rotron fan. The controller had no problems varying the speed of the fan, but the fan made a noise coming from the motor not the air movement. This noise was more pronounced at lower speeds. This is a problem with PWM fan controllers. .Some fans will produce a lot of noise when used with a PWM controllers. Somewhere on the net I saw a PWM construction article that discussed this and how to eliminate the problem. Someday I will start looking for the site and try to fix my PWM.
wizard115 said he bought a fan controller from SVC, and it worked for him.
http://www.svc.com/fanandtemman.html
They have a large selection there, but I did not see any thing that would handle the 2.26 amps (27.12 watts) my fan requires. I think its kind of asking for trouble (I could be wrong about that) with a lower rated power transistor.
I did a fast scan of the Comair Rotron data sheets and did find a fan with 12H2 in the part number. It only has terminals (no wire leads) and ball bearings with no other optional features. If they are consistent with the nomenclature after the voltage, it would indicate that your fan does not have speed control built in.