Not sure if I'll be doing all that right now but if it is electrical I would imagine turning off the steam switch would immediately engage power to the brew boiler, it does not. It waits for the steam boiler to cool before coming on intermittently.

@Jim I'm using Eric's thermometer.

rennix wrote:@Jim I'm using Eric's thermometer.

OK, so it turns out I was completely wrong about what I thought was a "remarkable" rate of cooling

This morning, after pulling a shot, I turned off my QM Alexia (not a double boiler, but the brew side should be fairly similar to your's). To my surprise, the grouphead temperature drop I measured is pretty similar to what you reported.

After five minutes, the temperature had dropped from a little over 92.5C to a little under 86.5C. So I measured a drop of between 6.0C and 6.5C during the first five minutes after killing the boiler heater.

Either the brew boiler thermostat in your Junior DB is being badly fooled by the rising ambient temperature, or the control logic in the machine is killing the brew boiler heater while the steam boiler heater is active, as Eric suggested. Either way, the group temperature drop seems to be consistent with complete loss of power to the brew boiler heater.

Jim

I just found this on the Auber website http://www.auberins.com/index.php?main_ ... cts_id=197.

It seems to be a bit shorter (~80 mm from the tip to the end of the thread) vs more than 90mm in the pictures that Jan posted, but probably it's more sensitive and doesn't need to be in the water as much.

That seems to be the perfect solution for anyone wanting to PID a Vibiemme Junior DB: $34.50 for the sensor, $35.95 for the 1/32 DIN controller (which can be easily put under the machine, the legs seem to be tall enough, and the sensor has a 3 feet cable, more than enough to go all the way), another $19 for a 40 A SSR (bolted to the underside of the machine with a dab of thermal grease, to act as a heat sink) and a few extra $ for the DIN box to house the PID controller itself. If you are the kind of person who likes overkill, a 80A SSR for less than double the price of the 40A would be even better .

Can anyone who owns the Junior confirm that there is enough room for the PID controller under the machine for the project box Auber sells (1.38" high)? For less than $100 this seems to be the perfect solution to the temp stability problems, and would make the Junior DB an incredibly interesting machine, a PID-ed dual boiler with a real E61 group for ~$1,500... almost in a class of its own

Installation-wise, it seems almost too easy to be true, and wouldn't require any specialized tool or skill (outside of not getting electrocuted when connecting the wires). And the kit could be installed to be easily reversed, with no permanent damage to the Junior.

I have an email to Auber to confirm that the thread will not damage the fitting on the boiler

Roberto, that's very good detective work - some readers of this thread should be thanking you.

The gentleman who responded before you, Jim Gallt, also puts together some very nice PID kits for some of our espresso machines - http://www.pidkits.com/ . However, a kit (as you probably know) is much more than a list of parts. It involves, parts, wiring, detailed instructions, and hours of beta testing to say the least.

The thermostat in the production Vibiemme Domobar Junior DB is, I believe, a Prodigy Italiano TR/86. This is a bulb type of thermostat whose bulb contains a gas which reacts to temperature changes, operating a on/off switch much like a typical pstat. A very similar thermostat is in the Francis Francis machines. Taking the opposite viewpoint of what I said before by assuming the electrics of the two boilers are not intertwined, this may be a nice solution for a machine having brew boiler thermostat problems.

The legs are about 1.25" but couldn't you just unscrew them a bit or put them on felt/rubber pads?

Use this Bud Industries box for 1/32 DIN. It fits under the Vibiemmes with no additional space required and is simple to machine with hand tools, a doddle with a mill.
CU-124-B mechanical drawing. -B is black paint.
I added a vent along each side and in the bottom to remove the minimal heat buildup for my PID project.
The box can be mounted under the machine with double stick tape, velcro, CPU heatsink adhesive, epoxy, RTV silicone, JB weld.

Use plastic or metal sheathing to protect the wiring fed through the vent slots.
Use separate sheathing to separate TC from power and control leads.
Use twisted wire pairs to minimize noise transmission / pickup.
Use different color 105°C minimum wire for AC power and DC control.
Follow the color convention for your location so you can fix it later.
Make a drawing of what you intend and have someone review it if at all uncertain.

Have a drip loop

Thanks for the nice words Eric.

Yes, I do realize that to install a PID would require some rewiring (and likely a certain amount of mechanical work), so calling the 3-4 components a "kit" is a misnomer. Still, compared to what it would take to install a PID without the proper sensor (figuring out how to get a J-type thermocouple or RTD in a good location, and doing the mechanical work), this is a much simpler proposition. I'm pretty handy when it comes to electronics and wiring, so I'm pretty confident that if the sensor works, the rest is going to be relatively easy

Bummer on the legs, just a bit shorter than needed. But the PID module itself is actually only 1" x 2" x 3" (H x W x D, or more accurately 24x48x75mm for the more metric oriented amongst us ), so it's just a matter of finding a smaller project box (probably one of the ugly RadioShack or Fry's ones), or bending some metal to make a box (probably would be enough just to bend a U out of a 1" thick strip of steel, but I need to figure out if there's any risk of water leaking down there)

The concerns about temp stability were the only think keeping me away from a Junior DB (I was leaning toward a BZ07, which I would have gotten already if it weren't backordered), so I think I'll go ahead and order one right away.

Unless someone else does it first, I will take plenty of pictures and document the process. I will very likely try and wire everything so that it can be easily removed (and that implies cutting new wires and adding the proper connectors). PM me if there's any interest in a pre-assembled bundle of wires, it might be easy enough to make a few sets in series. Once I get my Junior, that is

robca wrote:Bummer on the legs, just a bit shorter than needed. But the PID module itself is actually only 1" x 2" x 3" (H x W x D, or more accurately 24x48x75mm for the more metric oriented amongst us ), so it's just a matter of finding a smaller project box (probably one of the ugly RadioShack or Fry's ones), or bending some metal to make a box (probably would be enough just to bend a U out of a 1" thick strip of steel, but I need to figure out if there's any risk of water leaking down there)

BUD CU-124-B fits with stock legs.
It can be milled to fit in 15 minutes, an hour tops with hand tools

Wow, fantastic! I would be really happy if you could report on the outcome of your project. If it turns out to be fairly easy, I will certainly give it a go myself!

Sir Anselm wrote:So, I'm thinking about ways to get control of the temperature on my Jr DB. One option is to get the kit from Chriscoffee, check the temperature at the grouphead and adjust accordingly. The other option, that speaks well with my gadget-geek personality is to install a PID. There are lots and lots of information about people that has done this on their Silvia's, but I haven't managed to find anything about installing it on a Vibiemme Jr DB. So I turn to you, fellow home-baristas

So, number one. Is there anyone here who has done this? And can give some kind of hint regarding complexity of the operation? Perhaps somebody has pictures of an Jr DB with PID installed? I am pretty handy so I think I can manage, but then again, if it requires drilling into the boiler I think that will be a bit too much

Number two. I have been scanning the Ebay looking for suitable components, anyone know which ones are good, or which I should definitely avoid?

Hej Sir Anselm

Maybe Systermann.de can help you or give you some ideas/advice....

Have a nice coffee day.

/Wolff