I posted this to a lever thread, but thought I should give a heads up here.

Dwyer Instruments (Love division) is manufacturing and selling a thermocouple temperature switch (similar to the Brewtus stock controller) for $50. This is a simple on/off control with programmable hysteresis (e.g. turn boiler on at 122C, off at 124C). The really nice feature is that it includes a 16 amp rated contact, enough to drive most home espresso machine heaters comfortably, therefore does not require a separate SSR.

Info: http://www.dwyer-inst.com/htdocs/PDFFILES/iom/temperature/TCS_iom.pdf

To buy: http://www.dwyer-inst.com/htdocs/temperature/SeriesTCSPrice.cfm

For many applications, one wants easily settable reasonably tight temperature control, but the final shot temperature has so many other factors that PID is overkill. Steam boilers on dual boiler, lever or HX machines, as well as the boilers on smaller machines like the Silvia, come to mind. This unit could cut the cost to 1/4 of a PID, and simplify installation.

I've bought one to use with my Peppina. I will also assess whether it's useful for the Tea's steam boiler and for an ultra secret temperature control scheme I'm contemplating.

OK, you've twisted my arm. See my post in Knockbox.

lennoncs wrote:They also make a dual PID in 1/32 DIN format.
Nice company to deal with, they return calls and will actually give you an opinion.

Sean

Cool? How much? I'm looking for a dual loop cascade controller for my roaster.

cannonfodder wrote:I have ordered one unit to use as a temp controller on my lever machine, but I got to thinking (be afraid, be very afraid) would the thermocouple unit make an acceptable replacement for the good old pressurestat?

I looked at the specs, but not being an EE, I was unsure of some of the specifics. It looks like you have a ± of 1 degree on the accuracy, I can live with that. But my question, what is the dead band on the unit? It looks like you can set the time between heating sequences as well as the threshold. So if I were to order another unit, mount it in the front of my Isomac (like the brut) could I gain a tighter temperature control on the boiler? I would be mounting the type K TC in the boiler via an omega lock fitting.

Way I read the PDF, one can set the deadband by 1C or 1F steps. Commercial pressurestats translate to about a 2C to 3C deadband; there's a new Mater or Ceme tight deadband model that is down to 0.1 bar, or just under 1C. In an HX machine, with all the intermediate buffering, the major advantage of a pressure switch is that you can set it easily and repeatedly. However, the benefit of such quick changes is unclear to me, since the final brew temp has so many intervening variables. I'm more inclined to use one as a grouphead temperature controller.

A note on these units' availability: They do not ship immediately; mine's scheduled for 12/28.

cannonfodder wrote: I am not sure about what I should hook up to the NC, COM, and NO line.

This set is the output -- a switch. COM is attached to the power. NO (normally open) is the side of the switch that is open when the relay is denergized and closed when it's energized. The NC contact is the other side of the switch and is closed when the relay coil is denergized. I read the documentation: "the output is on" to mean the coil is energized, and that you connect to the NO side if you follow the heating and cooling declarations in the setup parameters as outlined. However, I personally would take an ohmmeter to the contacts, and just run it on the bench at room temperature to make sure.

Why is it everytime I bang the drum for a product, I'm always the last to get it? Maybe I should just shut up.

I got the 5011, I'll put up with farenheit if it gets me the thing a month earlier! Come to think of it, it makes for a tighter deadband too.

I'll be interested to read your result.

barry wrote:jim,

don't fret the ship date. when i ordered mine a few months ago the indicated ship date was a couple of weeks out but the controllers showed up in a couple of days. iirc, they ship out of chicago, so you should have it pronto.

Thanks for the tip. I emailed them to check; so I'll know what's happening soon. In the mean time, I'm practicing my 5/9ths multiplication table.