Happy Thanksgiving!

I've been marathon roasting some Brazil minas gerais for a client in 411g batches and am noticing that about every other roast the chaff is not getting vented properly, but getting stuck somewhere in the tube. I'm also noticing in the few bits of chaff that do vent, lots of moisture in the screen. I assume that moisture is combining with chaff and clogging the vent tube - and probably not good for the roast profile at all!

Any ideas on how to solve? I am not certain of the moisture content of the green I'm using.

Also, ambient info: am roasting outdoors in about 40degF.

Thanks for any tips.

PS also - any tips on how to clean the Huky venting/tubes?

Most Brazils are naturals, with way more chaff than other origins.
For the Gene it's recommended to load smaller batches and to clean chaff holder more frequently. Works for me.

I normally use a shop vac.. Works great after each roast

Are you using the damper?
I switched to a cheap lamp dimmer and that problem went away; along with a momentary bump of high air then back to the low setting on the dimmer. I'm starting this air flow pattern after the drying stage is complete; maybe once every minute.

When I took the cyclone off of the plastic bucket it drops the chaff into I was quite surprised to find how damp the chaff was.

There were 4-5 inches of chaff and they were still somewhat fluffed up, but they were definitely damp.

I just got a similar setup as SJM running and I was also a bit puzzled by the amount of moisture inside the cyclone and dust bucket. I had to wipe out all of the chaff, instead of just turning the bucket over... I guess the length of the system cools the exhausts down enough to make the water condensate before the end of the exhaust duct. I take it the problem is similar to what you experience, even though the setup is different. Given the (I guess) standard setup and the fact that you are roasting in almost freezing temperatures, you can use a bit more fan throughout the roast. (Many of us uses some kind of dimmer to be able to run the fan continuously. There's lots of info on it in this forum.) Anyhow, as this happens outside of the drum and presuming that you still gets good roasts, I wouldn't worry to much about it. The exhaust is cooling a bit faster than expected, thus some condensation in the end of the chain. It's the same phenonemon as some water dripping out of the exhaust of your car.
I have been running most of my roasts with the Huky in a standard fashion, i.e. with the ordinary "extended" J-pipe, through a funnel and a sieve with a dedicated exhaust fan and and exhaust bowl so that I could direct the smoke through a duct out the window. Then I wasn't bothered with any excessive damp and the pipes seem reasonably clean after use. (There is of course a thin layer of some smokey and oily residue, making me think of *bucks. ) This was in normal room temperature (20C, 72F) though, so the cooling effect isn't the same as you are experiecing.
A bit more on this: In a full load, 500g, you will drive some 60-80g of water out of the beans (plus some chaff and something else, coming out as smoke etc.). But I think that even more will come from the air circulation, which as such is part of the scheme for the roast. That air humidity is of course depending on where you live and what the weather's like at the moment. (It's been foggy, damp and a few degrees above freezing for a couple of weeks here around Stockholm now. 3 hours of sun in total for the whole month... Cold and damp, sounds like London. )