HI Gang... (This is sort of a modified cross post from the equipment forum)

I am seeking an effective thermostat for my recovery still. We use a plumbers delight on an appleseed at atmospheric pressure. I take the recovery stage all the way up to 212 F in the belief that this gets all of the methanol out of the fuel / glycerol.

I understand from this forum that copper is a general no-no. I believe this is for long term fuel stability issues...

My question... is a little bit of copper in the system a problem?


My local HVAC shop can get me an aquastat that works in the right range, but it is the kind that uses a probe in a little copper well. So if I used this, all of my fuel would be flowing over this piece of copper as I circulate it over and over.

Is this a major concern? The aquastat costs about $70 so I figured I would check here before buying. If you have a better idea for temp regulation that would be swell... I just need a high temp cutout for safety. Currently we bypass the stock thermostat on the water heater AND the high limit popout switch at the top of the heater.... this makes me a little nervous in case I have a stroke or something while the process is running...

Thanks for your feedback.
Farmer

you might look into getting a PID, SSR and a thermocouple. on Ebay you might be able to get all 3 for less than $70.

-dkenny

Because of the flamable vapours be aware of the fire risk....

Most industrial controls intended for this sort of aplication are extremely expensive compared to standard stuff because the liability risks and extra steps needed to manufacture test and certify.

Be very careful you don't create a situation where the parts you chose can cause an arc.

quote:

PID, SSR and a thermocouple

Farmer,

TroubledGus made some great points regarding the arc possibility, but I use a wet-bulb thermostat and place it about 6 feet away from my system to allow for the arc. Also remember that the bulb can be placed outside of the tank (like mine) and then adjust for the small temperature difference (about 8 deg for my system). Additionally most PID/SSR controllers will need an additional relay to account for the heater load.

Have fun,

Rich

Thanks guys for your quick feedback. That is a good point about the arc. Our setup is designed to be vapor free but you never know.

RichE320 what are you using for an aquastat? I think the high temp Honeywell I am looking at has the sensor bulb mounted close to the back of the control, but I could be wrong.

Thanks,
Farmer