Just purchased a Blichmann BoilerMaker G2 (10 gallon) and a HopBlocker. Doing full boil with extract kits (moving a step closer to AG).
I have found it to be very difficult to whirlpool with the HopBlocker in place. I've tried using a mix-stir attached to a drill and even attempted to stir with a paddle but didn't get a good whirlpool.
I also noticed that my immersion chiller won't fit with the hopblocker installed, when I lifted out the chiller, the outer sleeve of the hopblocker raised up all the way.
Any suggestions?
Assuming you are using a copper coil immersion chiller, I brewed an all-grain batch (8 gallons into the pot) with the same set-up this weekend. I was able to cram the coil in behind the HobBlocker. It was a tight fit, but I made it work. Coil diameters vary, so yours might need more room in the pot. I leave the chiller in the pot until after I've drained the wort into my fermenter. I didn't want to disturb any of the hop debris cone formed by whirlpooling before transferring. Leaving the coil in should eliminate the problem of the sleeve riding up until you pull it up.
I use a pump to recirculate, so it's just wort flowing from a hose. But, I had a problem with my recirculation system a few weeks back and resorted to an old stand-by - a big metal spoon from my original extract kit. I only ran the spoon down a few inches, just a little more than the head submerged, and gave it a brisk stir around about 1/2 the side of the pot. A couple of minutes of vigorous stirring started a pretty nice whirlpool. I gave it a couple more gentle stirs during the chill. You don't need a well defined vortex in the pot to achieve decent whirlpool results.