Install a PID on my Vibiemme Junior DB?

by **Sir Anselm** on Thu Sep 30, 2010 4:30 am

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 :mrgreen:

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 :wink:

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

by **da gino** on Thu Sep 30, 2010 5:04 am

I installed an Auber PID for a friend's Silvia. It was very easy and didn't require you to be very handy. There was no drilling in the boiler, just attaching the probe to the outside. I wonder how accurate it is with the probe on the outside, but my hunch is that no aftermarket PID's would require drilling into the boiler. Someone should correct me if I'm wrong as this is just a guess. I can't recall any steps that were particularly unique to a Silvia, but I'd confirm with your PID manufacturer.

As an aside I would put a PID on a DB or a SB machine if I already had one like you do because it would make temp control so much easier, but have an HX and have no desire to have a PID on it or to trade it for a PID DB machine because temp control on an HX is quite easy and pretty good if not quite as precise as some achieve on a DB (I can't control it down to .1 degree).

by **cafeIKE** on Thu Sep 30, 2010 1:24 pm

You may be able to fit a sensor in the the bulb thermostat fitting.
Outside the boiler may not be optimal on a larger boiler.

Plan carefully before starting and the job should be relatively easy...

decide where the wiring will go. PID power, control and sensor wires need protection if exiting the body.
decide where the PID will be mounted. Stainless is hard to machine.
use wire rated for 105°C operation and get enough colours to avoid mix-ups
use quality connectors and tools. Heat, water and poor connections do a disaster make
take photographs and make notes of everything you will change
get an electrical schematic of the machine from Vibiemme or vendor
get everything together before starting and make a couple of dry runs

by **janweel** on Tue Oct 05, 2010 5:56 pm

I'm also planning to PID the vibiemme double junior.

The easy part:
* The PID controller: It's best to have one with fuzzy logic
* Solid State Relay: I think it needs at least 25 amps

The not so easy part:
* To get an enclosure for the PID. You can get one at auberins.com. The problem for me is that they don't ship the enclosure outside the US

The hardest part:
* To order the right thermocouple for the brew boiler. You will need (i think)
** Length about 90 mm
** Diameter about 6,5 mm
** The fitting has (i think to be) 1/4 inch. The problem is however that i'm not sure about the threads in the fitting. Does it need to be BSP, NPT or Metric? I think it's BSP

Anyone any suggestions on the thermocouple? BSP, NPT or Metric?

http://users.rcn.com/erics/ · by **erics** on Tue Oct 05, 2010 6:56 pm

The only "problem" I've seen with the Vibiemme Domobar Junior (and keep in mind that this is one hands-on experience + another concurring email) is that the potentiometer for the temperature adjustment is very sensitive to slight movements. A nice fix (talk is cheap) would be to have some detents built into the rotary switch.

Fittings and thermocouples are readily available to do what you want - some pics of your brew boiler would be helpful and, MOST IMPORTANTLY, plan the operation before you start "pulling wires."

by **cafeIKE** on Tue Oct 05, 2010 7:39 pm

janweel wrote:The easy part:
* The PID controller: It's best to have one with fuzzy logic
* Solid State Relay: I think it needs at least 25 amps

IMO, on an e61 group, there is no benefit to fuzzy logic. The group is a million thermal miles from the control point. As long as the boiler maintains temperature within a reasonable band, fuzzy logic is DLB tech. Extensive tests controlling the boiler to within ±0.3°F v ±2.0°F make little difference on the business end of the group.
The heater element is 600w / ~3A @ 220v. A 5A [10A on 110v] relay with adequate heat sink will be fine. An improperly mounted 25A may fail. Check the relay data sheet !!!

by **janweel** on Wed Oct 06, 2010 2:24 am

The temperature management in my Vibiemme Junior DB (unmodified) is too unstable. I installed a temperature probe on the brew boiler. That gives me a good insight in the brew water temperature. Unfortunately i still have to adjust the thermostat screw a few times a week. Of course the group head gives some stability but you will clearly taste the temperature variations of the brew boiler in the cup.

by **cafeIKE** on Wed Oct 06, 2010 10:29 am

What sort of temperature variation are you having?

Every shot is different, even with 0.0° variation.
How much can be ascribed solely to temperature?

by **janweel** on Wed Oct 06, 2010 3:51 pm

Today i had brew boiler temperature readings* from 87 C - 94 C without adjusting the temperature knob. Before measuring the machine was on for at least an hour

My experience so far regarding temperature on the vibiemme double junior.
* The brew boiler temperature will rise too high when the machine has been on for a few hours
* Also the mean brew temperature will drop when the steam boiler is switched in the on position. I think that the thermostat is getting to much ambient heat from the steam boiler. That's because the thermostat is directly placed above the steam boiler.
* Also the thermostat seems to be vulnerable to steam coming from the valve that sometimes releases pressure when the steam boiler heats up. The thermostat is placed directly above that valve and steam seems to make the thermostat more unstable.

* brew temperature is measured with an electric thermometer directly connected to the brew boiler

by **cafeIKE** on Wed Oct 06, 2010 5:44 pm

7°C seems excessive :shock:

Can you post a photo of the thermometer connection?

Have you contacted the dealer / Vibiemme?


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