Posted Wed Jan 14, 2004, 10:05am Subject: Re: Z&D Update
This is the top of the lid. I wish I could have used bounce flash. I also wish I focused better. Note the flare in the top of the tube. I left it because I thought it looks more finished and I thought it would be easier on the thermocouple wire.
Posted Wed Jan 14, 2004, 10:16am Subject: Re: Z&D Update
This picture shows how I passed the heater wires out for connection to the Variac.
Note the duct tape to protect the insulation on the wires.
Please note that I don't consider this the finished configuration. It is just a development step.
If I continue with the Variac I will have a plug on the roaster into which the Variac will connect and a line cord (properly strain reliefed) from the heater to plug into the Variac. I am thinking of increasing the heating element to ~ 600 Watts and using an incandescent lamp dimmer to control it. All that should fit in the base of the machine.
I have some pictures with the bottom cover off showing the connection of the heater leads to the PC board.
Posted Wed Jan 14, 2004, 4:48pm Subject: Re: Z&D Update
Here is a bottom view with the cover removed. The wires at the left coming out from under the metal peice are the heater leads. The other end of the leads are pulled up near the top right of the board. The little black boxes near the right of the board are relays. No doubt one is for the roast chamber heater and the other is for the cat heater.
Posted Thu Jan 15, 2004, 3:44pm Subject: Re: Z&D Update
I have done several roasts with the Variac. Last night I roasted some decaf Colombian from Costco for my wife. (don't laugh after resting overnight, this stuff smells good enough to tempt me to be a decaf drinker)
This time I filled the chamber to the normal fill line. I did preheat the machine.
I did the clone of Jim's Hot-top clone.
I have an old Graylab darkroom timer. I put peices of tape around the clockface with the temperatures on them. As the hand on the timer approachs a new temperature I turn the Variac knob up or down depending how far I am from the desired temperature and the rate at which the temperature is moving.
I was able to come real close to his profile except the very begining. This was a funny story. Since this is a new setup and I am still in the learning curve I had my DVM hooked across the heater. The digits on the DVM are about the same size as those on the thermometer. At the start of the roast I turned up the Variac. The temp didn't seem to be ramping fast enough. I turned it up full. I read about 136 and it was holding steady. I then realized I was looking at the DVM, not the thermometer. I turned down the Variac and bumped the hand on the Graylab up to match the 250 degrees on the thermometer. The rest of the roast proceded on schedule.
I would say that if you don't mind one extra peice of equipment in your setup, there is no reason not to use the Variac. My rangetop is getting crowded with the Z&D, the HWP for bean cooling, the thermocuple meter, and the Variac. The crowded setup is what is prompting me to look at a higher wattage heater and lamp dimmer.
The Z&D load of beans turns out to be a large load for the HWP. After getting the beans into the HWP and starting the cool cycle in it, I have to pick it up and rock it in a cicular motion to keep the beans agitated.
Posted Thu Jan 15, 2004, 8:57pm Subject: Re: Z&D Update
I think a variac would be nice...then I can use it on the gourmet as well. I thought it was gonna cost me an arm and a leg....but when doing some searching on Jims hot top clone....I came across all kinds of posts..and found his review of the krm 590 from coffee bean corral. ...too bad I just got an order from them not too long ago. But, I guess I'll need more green beans sooner or later right?
My girlfriend already thinks I'm nuts...but she loves the fresh roasted beans. The other night, I caught her sneaking off with the french press and some beans that she just ground up. She was off to a meeting and couldn't bear the thought of having to drink the coffee there. I just chuckled and called her a snob....she replied that she's not a snob, she's just spoiled now......
But I agree with Jim....the Z&D does roast very evenly...and will be even better with using a good profile.
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