Izzo Alex Duetto PID issues

by **TomC** on Mon Oct 03, 2011 9:04 am

Any other recent converts to the Alex Duetto II, please jump in.

I'm curious what your PID readouts are saying after you dial in your temp, specifically your brewhead temp. I'm wondering if I have a faulty one and want to see what the norm is out there amongst the rest.

I can set the PID and get +/- 3 degrees during, before and after pulling a shot. The only way to get close to my set temp is to drain a good deal of the reservoir to flush the head, to get the temp right. I wasn't expecting to temp surf on a DB.

I realize some variability would be normal, but the main reason for my post is in addition, I'm having stuck PID control issues. There's been twice now that I have not been able to adjust the PID on either temp, on the fly, without completely shutting off the machine and letting it cool to room temperature. Then fire it back up and it would work again. Its done this twice now, and the buttons are acting a bit wonky.

An email to CCS last week has gone un answered, but I think if I have ongoing problems, I will just call them directly. They seem pretty helpful once you just pick up the phone. If it was a temporary glitch, then no problem, but I don't want to be setting myself up for more problems down the line.

by **cafeIKE** on Mon Oct 03, 2011 2:54 pm

e61's vary with ambient conditions.
e61 ambient search

The temperature profile varies with the shot volume. The slower the flow, the more the group cools the water.

Forget about the boiler temperature. Especially forget about boiler offset.
Adjust group idle to about 5 or 6 [YMMV] degrees below desired brew temp.
Flush about 5 [YMMV] seconds, wipe, load and pull.

Adjust by taste.

by **jasonmolinari** on Mon Oct 03, 2011 4:02 pm

If you're seeing +/- 3 degrees, you should be averaging right at your target, no? So the grouphead should be at target temperature from the thermosyphon, and should cool or heat the incoming boiler water if it's a little high or a little low at that exact moment.

Am i misunderstanding your question?
My Alex Duetto PID shows sometimes a couple degrees overshoot or under after pulling a shot for the brew boiler temp.

http://users.rcn.com/erics/ · by **erics** on Mon Oct 03, 2011 4:26 pm

Here is an exhaustive and well written study of the Alex Duetto - admittedly 3 yrs old but still very applicable to the current offering. Temperature study of Alex Duetto .

I'm having stuck PID control issues. There's been twice now that I have not been able to adjust the PID on either temp, on the fly, without completely shutting off the machine and letting it cool to room temperature. Then fire it back up and it would work again. Its done this twice now, and the buttons are acting a bit wonky.

This is a separate issue and "sounds like" a heat related problem. Maybe see if you can avoid the problem by having the steam boiler off - certainly not a solution but would assist in troubleshooting.

by **TomC** on Mon Oct 03, 2011 10:56 pm

More reading to do, but I look forward to it.

No, I wasn't being clear in the initial post. It can be on for hours set at 199, and I walk up and see it at 196, or 202, without me doing anything.

If I don't do a long flush, it doesn't get to where I have the PID set at. If I do flush, usually by the third shot, the temp will be there.

And the separate topic, the buttons not working. That irks me. I will have to f/u on that, if it continues.

by **TomC** on Mon Oct 03, 2011 11:04 pm

cafeIKE wrote:e61's vary with ambient conditions.
e61 ambient search

The temperature profile varies with the shot volume. The slower the flow, the more the group cools the water.

Forget about the boiler temperature. Especially forget about boiler offset.
Adjust group idle to about 5 or 6 [YMMV] degrees below desired brew temp.
Flush about 5 [YMMV] seconds, wipe, load and pull.

Adjust by taste.

I've read some rock solid advice and posts from you, so I always seriously consider what you have to say. I'll look up your links you're mentioning. But if by ambient conditions you mean my actual ambient temp and humidity in my home, then I gotta say, a counter argument is that my apartment is always within about 5 degrees year in and out, despite the month, and the humidity never really changes. I'm 500 yards from the Pacific Ocean. It's not like the function is suddenly different after "hot dry summer days" rolling into a "cool damp fall".

To be honest, my bigger concern was the fact that they would not work when they should have. I was just curious if other Duetto users were noticing temp wandering on their PID's prior to pulling a shot or flushing.

by **cafeIKE** on Tue Oct 04, 2011 12:09 am

TomC wrote:No, I wasn't being clear in the initial post. It can be on for hours set at 199, and I walk up and see it at 196, or 202, without me doing anything.

Just to be perfectly clear : from your initial post it sounds like you have Eric's adapter to read the group temperature.

What is going from 196 to 202? Group, Boiler, Both?
None should

TomC wrote:I'm 500 yards from the Pacific Ocean. It's not like the function is suddenly different after "hot dry summer days" rolling into a "cool damp fall".

Is there an open window anywhere near the machine? The merest breath can cool the group by a few degrees. I once did a steady state test wherein I ran the air con FAN ONLY. The air con vent is about 8 feet above the floor. The flow is barely detectable about 6 feet from the vent and the machine is 15 feet away. The ambient temperature at the machine went up about 2°F due to warmer air near the ceiling being circulated down around the machine. Meanwhile the group temperature dropped about 2.5°F.

http://users.rcn.com/erics/ · by **erics** on Tue Oct 04, 2011 12:45 am

It can be on for hours set at 199, and I walk up and see it at 196, or 202, without me doing anything.

This is too much of a swing. If you had said "It can be on for hours set at 199, and I walk up and see it at 198 or 200 without me doing anything", that would be OK. See below for a boiler SIMILAR to yours, with a like temperature sensor and a Gicar PID. I just picked a representative 20 minute time period.

So, to me, you have two separate problems but both related to the Gicar PID. Yes, of course, they should be fixed but, at least they are not show stoppers.

by **Runaro** on Tue Oct 04, 2011 2:30 am

I had a similar problem with unstable brewhead temperatures on my Duetto a while ago. When I pulled water through the empty group the temperature was stable at 93C (set temp), it dropped to 92C just as the shot finished. The brew boiler light came on after about 20 seconds of the shot. However about 10 minutes later I pulled a double shot and the Duetto had a temperature rise from 93 to 97 at the end of the shot, before desending again. The temperature temperature was stable the first 15 seconds, then it started to rise steadily to 97. I was sure I had problems with the PID but it turned out to be a copper tube in the heat exchanger that was missing! Maybe an Idea for you to check out if you have a similar issue. You can try the following procedure:

1. Loosen completely the two nuts marked with the green arrows......then withdraw the T piece with the OPV and discharge tube attached, it will form a T shape. At this point examine the level of water in the brew boiler, it should be full.
2. The silver elbow fitting marked with an orange arrow then needs to be removed from the top of the steam boiler.....this fitting thread sealed in and will be difficult to remove. Be very, very careful and ensure someone is available to support the steam boiler with a strap wrench or similar (so it doesn't twist)....don't try to use a bar within the other fittings for this, they will snap off. Careful inspection of the silver elbow will reveal some flats where a good fitting spanner can be used to apply leverage. What comes out of the steam HX should look like the other picture (preheat fitting.jpg)......if it doesn't, have a fish around within the HX tube to see if it has fallen off. It could have done if Izzo shrunk fit it, but forgot to braze it.

...moderator removed copyrighted photos...

Mine was missing (only the silver elbow fitting was there) and after I got a replacement everything the Duetto has beet very stable, no PID problem.

by **TomC** on Tue Oct 04, 2011 9:28 pm

cafeIKE wrote:Is there an open window anywhere near the machine? The merest breath can cool the group by a few degrees. I once did a steady state test wherein I ran the air con FAN ONLY. The air con vent is about 8 feet above the floor. The flow is barely detectable about 6 feet from the vent and the machine is 15 feet away. The ambient temperature at the machine went up about 2°F due to warmer air near the ceiling being circulated down around the machine. Meanwhile the group temperature dropped about 2.5°F.

I don't have anything adapted into the Duetto. It is stock. I wouldn't modify it anyways, other than adding the different steam tip that they provided me with.

It sits in my kitchen, 20 feet away from the nearest window, no drafts. Hell, I don't even have central heat or any AC. I don't think the temp in my kitchen fluctuates by more than 10 degrees year round.

I have Eric's adapters for thermocouples on my Quest M3, maybe that led to the confusion.


Contact Us	Legal disclaimer and copyright: This content and all its parts are copyrighted, all rights reserved. Content including all text and images in part or in whole may not be reproduced in any electronic or printed medium without prior permission. Home-Barista, Home-Barista.com and related logos are trademarks of Home-Barista.com, LLC. Other trademarks are the property of their respective owners. By accessing this site, you agree to the terms of service. Overall speed: , current page: s, avg: s, max: s