Boiler PID Sensor Problems with 3rd Wave Water - Page 5

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#41: Post by ira »

I will say though that it bothers me that water is being pointed at when it seems it can't be the cause of the problem. It distracts from finding the actual problem which might be as simple as a badly set parameter in the PID. Like does it have a setting for "Heat for this long at 100% for the first N minutes" which could randomly cause this problem depending on initial starting temperature and water level?


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another_jim (original poster)
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#42: Post by another_jim (original poster) »

The reason the people at First Line suspect the water is that they do a test start up on the machines before sending them out. When I was posting in the Bianca thread, I thought is was a bug in the Gicar PID (that would effect ECM, Lelit, and Profitech). Now, on this thread, people are reporting that problems persist even when they change water. So, other than being something intermittent, the cause is not entirely sure.

I've edited the original post to reflect this uncertainty.
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#43: Post by Rufus T.F. »

Has there been any response on this from either of the producers, Gicar or coffee machine companies?


#44: Post by Nate42 »

Even though the jury is still out on whether water is the culprit, I would still recommend owners of these style of machine (and any machine really) fill their steam boilers with very soft water, and purge and refill occasionally to keep concentrations of minerals and other impurities from adding up. Distilled water plus a dash of baking soda for insurance (or tap water if you know your ph is higher than 7) is probably a good choice. You want your steam boiler water to be mostly pure but not acidic. Water that is too pure will become acidic as it absorbs CO2 from the air.

As has been discussed here and elsewhere, since you typically only remove steam from steam boiler, mineral concentrations (no matter how small) will build up over time. There is no downside to following the advice of using mostly pure water and periodic purges, and there is also no taste benefit to using special water formulations in the steam boiler. It may or may not prevent the problem being discussed but still falls under the "just do it" good advice category in my opinion. If your water differs significantly from what manufacturers tested with, its not at all out of the question that strange and difficult to predict results occur as concentrations increase over time.

For what its worth, I'm no chemist myself but I do work for Thermo Orion, and we make products for measuring water quality and producing ultra pure water. Water chemistry and material compatibility is quite complex even to the experts. Also, I've tuned more than a few PIDs for various applications in my life, and a film that slows down sensor response but has little impact on final long term accuracy can absolutely cause overshoot or instability in a PID system. This can be "cured" by slowing down the dynamics of the PID tuning, but for best results you want your sensor to respond as fast as it can. PIDs aren't magic, they depend on the dynamics of the system being measured and the measurement system itself for repeatible results.


#45: Post by Bluenoser »

I'm not sure of the construction of the probe.. but any chance the actual sensing element could be getting damp through some flaw in the probe? I remember building water immersed temp probes and the biggest problem we had was getting it sealed properly. Taking the probe out, cleaning it and drying it out might cause it to perform fine, until some dampness permeates.. Just a guess. A new probe would rule that out.. although it still could be caused by a film.. I am surprised if such a film that isn't visible could cause the probe to slow down that much.

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#46: Post by Jeff »

Interesting that a relatively new machine seems to be impacted by the mysterious overpressure issue. The poster's photo shows the steam-pressure needle "wrapped" into the brew-pressure area.

Lelit Bianca User Experience
moryanzi wrote:Hi, i'm a new bianca user, got my brand new bianca just 2 weeks, about 4 shots per day.

But starting yesterday, after about ten minutes of power on, the steam pressure gauge will rise to a very high position, and the PID screen display is still in the ready state (the temperature number is flashing). The steam pressure gauge will drop a little after a few minutes. Open the hot water head or steam head to discharge for a while, the pressure gauge will also drop back to about 2.5Bar.


#47: Post by kaptain_zero »

I believe the problem is that manufacturers have switched to using temperature with the PIDs instead of like the old pressure stats which operated on pressure. They could have used a pressure sensor instead of a temperature sensor (with the same improvement of PID accuracy) and it would be able to detect any over pressure conditions. A temperature sensor will not detect boiler pressures, just the temperature which is only fine if everything else is working. If the boiler overfills for some reason, the normal temperature will now result in an over pressure situation without the PID detecting it.

Naturally, everyone is trying to manage the "temperature" of the boiler to minimize any swings during shot pulling (because that's what customers want), but that method does not control the pressure and is now something that concerns me a bit as I have PID on my HX machine. I don't mess with my water, I use regular carbon filtered tap water in my Profitec Pro 500 and just chuck one of those Rocket water softener packs in the water container and call it good. Still, should the water fill probe circuit fail to shut off, the boiler would overfill and with the PID insisting on the set temp, the boiler WILL be too high in pressure and that is dangerous. It is very unlikely a coating on, or leak in, the temp sensor, but rather overfilling of the boiler that is the problem with these units... in particular because the PID keeps reporting it's at the correct temperature (a failed probe should trigger a shutdown).

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#48: Post by bzarycranski »

Jeff wrote:Interesting that a relatively new machine seems to be impacted by the mysterious overpressure issue. The poster's photo shows the steam-pressure needle "wrapped" into the brew-pressure area.

Lelit Bianca User Experience
For the record, this behavior also occurs with my Lelit Elizabeth v3 so this isn't necessarily a Bianca problem. The common thread between these two models is Lelit but this doesn't necessarily prove this is a Lelit only problem as Jim at 1st Line says he has seen this behavior in other brands with PID sensors.

To be continued. My next step is to switch from Purified Drinking Water with minerals added to bottled spring water (Deer Park, Poland Spring or Crystal Geyser when I get back to our shore house.


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#49: Post by Jeff »

Excerpt from Lelit PL62T PID boiler temperature very high and fluctuates
sho1sho1sho1 wrote:When I power on the machine from cold, boiler temperature would rise. When the PID reading gets close to 100C, the the issue starts. The PID reading would jump from 100 to 110 to 95 to 120 to 130... and the steam pressure would get very high to 2.5 bar. In the first month or so, it would do that and then settle back down to 120C to 121C and steam pressure down to 1.5 bar will be ok. The flush would put out lots and lots of steam and it would take 15 to 20+ seconds to purge all the steam.

In the second month, it got worse. A few times, the steam pressure went all the way to 3 bar and I heard clunking and popping sound from the machine. I believe that is the steam pressure safety valve relieving pressure. I contacted Lelit and they said this is not normal. The boiler temperature should be steady and steam pressure should be around 1 to 1.5 bar. I contacted my place of purchase but was put off by them.


I am not sure why the temperature probe was oxidized. I have been using the machine with the Lelit softener since day 1 and recharge is every 2 weeks. I have a water softener at home and my water is soft.


#50: Post by bzarycranski »

Yes, same/similar experience with Elizabeth which was blamed on using RPavlis water. I was instructed to clean the sensor and use Spring Water which only helped for a day.