Rocket Evoluzione V2 brewing super hot

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travis85904
Posts: 25
Joined: 8 years ago

#1: Post by travis85904 »

So I woke up today and proceeded to make my morning coffee. As soon as I turned on Erica group thermometer which I installed when I bought the machine, it gave a reading of 230 degrees fahrenheit. I immediately knew something was off as it usually reads around 202 at idle. Anyways I began my flush and ended up brewing a shot at 210 degrees :/. I'm pretty confident that the thermometer isn't just giving me an improper reading because the machine was steaming way more than usual when I began my flush. Anyways I'm wondering if anyone can shed some light on what's going on. I'm still brewing around 9 bar, and the boiler hovers between 0.9 - 1.1 bar so I don't believe the pressure is off. Please help, my machine is almost a year old.

h3yn0w
Posts: 476
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#2: Post by h3yn0w »

Bad PSTAT?

travis85904 (original poster)
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#3: Post by travis85904 (original poster) »

Yeah but wouldn't the boiler pressure be abnormally high if that was the case?

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erics
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#4: Post by erics »

Time to open her up and inspect, including pics of the pstat and boiler top.

It is POSSIBLE that the pstat contacts remained closed at some point (this is a 24/7 machine ?) and that would definitely drive the grouphead temp up. Yes, 230 F is unreasonable.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

travis85904 (original poster)
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#5: Post by travis85904 (original poster) replying to erics »

This temp swing seemed to be an isolated incident, until a few days ago when it happened again. First the shot pulled extremely cold, next it pulled extremely hot. That was a few ago and hasn't happened again since then.
So I opened the machine today but I'm not sure exactly what to look for. I took a pic and a video.

http://www.youtube.com/watch?v=OXBd-WrcW0A


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erics
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#6: Post by erics »

With the machine unplugged, remove the pstat cover as indicated below and inspect the contacts. Hold the contacts open with a small piece of wood and snap a pic or two.



With the pstat cover still removed, turn the machine on and observe the pstat operation.

Trace the blue and black wires from the pstat. If the pstat directly controls the heating element, it is likely that the contact(s) are in bad shape.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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homeburrero
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#7: Post by homeburrero »

Here's a video that might be useful if you have not already seen it:
http://www.youtube.com/watch?v=KJwq4wR8vds

Shows how to pull all the panels and also shows how to take the cap off the pressurestat so you see the contacts.

Your machine appears to be wired like mine, and like the one in the above video, which has the pressurestat switching both the neutral and the live side of the element current, via wires from two different high limit switches (one on neutral, one on line.)

If it has the standard Pro.El.inD/Rocket controller ,

then that pstat/hi-limit black wire does get line voltage via the controller ( resistencia pin), but the controller doesn't do the pressure cycle switching.

As to what's causing your malfunction, it is a mystery. If the pstat plunger were prone to occassional sticking, or prone to not opening because of some clog in the pipe, then both of those contacts would stay closed, causing the machine to overheat. If you were watching when this happens you would see the boiler pressure go high, then the group temp would also slowly rise. After the pressurestat plunger 'unsticks' itself, the pressure would return to normal first, and the group temp would stay high for a while, slowly returning to its normal idle temp. If it is something that only happens occasionally it may be hard to diagnose.

It could also be bad contacts in the pressurestat, but on this wiring scheme both contacts would have to be sticking closed at the same time for it to overheat.

Replacing the pressurestat is one option, but it is a rather expensive pressurestat to replace if you aren't sure that it's the culprit. You may want to remove it and look carefully at the connecting pipe to make sure it's not a matter of some sort of clogging there before ordering a replacement. That pressurestat should last years, but scale/clog problems after one year of use could be fairly likely depending on the water.
Pat
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