T500 Pot Head

[vino-tinto]

I am in the process of testing the new 54mm pot head I made to fit my T500 boiler. Because I didn't want to fit a temp guage to the boiler I fitted one to the bend at the top of the pot head instead.

So I tested it with plain water in the boiler for pressure and condenser operation and all went well so it's now ready for a cleaning run with some wash, my question is, what temp should I be looking for on the top of the pot head when running a wash.
I know when running the T500 with the reflux column I get the top of column temp at about 78C, but a pot head is another matter.

I have a power controller so can adjust the boiler accordingly.

[YHB]

After going to all that trouble to install a thermometer, you are now going to have to understand it is not much use really.

The thermometer will tell you the temperature of the boiling vapour, you cannot alter that temperature it is what it is. The temperature is a function of the strength if the wash and the strength of the wash varies as more alcohol is boiled off.

So as the run progresses the temperature will increase as time goes on not because you are putting in more heat but because the wash is getting weaker - when the temperature gets to 98degC you have water only in the still.

When you first switch on the pot the temperature will rise slowly, this is like putting your finger over the kettle spout when you first switch it on, but when the kettle boils and steam comes out of the spout the you burn your finger quickly. The same happens with the still, a slow rise in temperature then a sudden spike when steam passes over the thermometer.

So you can use a thermometer to check when the wash is boiling and when it has given up all its alcohol. And it gives you something to play with during a very boring exercise.

But apart from the thermometer being as much use as a chocolate fireguard, I am pleased that everything is going well.

Turn the controller to max until the wash boils and then turn it down until you have a this stream and that's it.

Let us know how it goes.

[vino-tinto]

Thanks for that Bri, you have just made it clearer. I had read up a bit about the matter but didn't quite get the gist.
So I should run the output rate by adjusting the boiler temp, strip to say 20% with the parrot and forget the temp guage.

[Myles]

I actually use a combination of a hydrometer and a thermometer.

For me the thermometer in the vapour path tells me when it is time to switch off the power at the end of the run. Slightly more convenient than the hydrometer and a bit easier to read.

I also use it at the beginning of the run, so that I don't need to put the heads through the parrot. During the run itself though I just use the hydrometer and parrot.