ECM Puristika heating issue ?

Puristika

Hi everyone ! I think i have an issue with my new ECM Puristika (it’s my first time with E61)

On a cold start, the machine goes up to 93 degrees pretty quickly (5 minutes i think i didn’t timed). But sometimes (not every time) the whole group stay cold/lukewarm, even after 20-30 minutes of waiting. I move the lever up, either in the first position (which I think is sort of a pre-infusion) or in the second position to make a flush (less than 5 secondes) doing that causes the temperature to drop 10-15 degrees on the PID at once, and the group starts heating it up normally.

Someone on Reddit (who have the same problem but more rarely) told me to remove the big o-ring around the reservoir top (he got an extra sheet in the packaging which said to remove the big o-ring, otherwise the machine doesn’t work).

I did it but the problem is still persisting…

DavecUK

Puristika Hi everyone ! I think i have an issue with my new ECM Puristika (it’s my first time with E61)

The symptoms are classic for a thermosyphon stall. The brew system is sealed and heats the group by a continual flow of water. Water enters the group from high up in the boiler (or the top of the boiler.

In this photo of the prototype Puristika I got way back in Jan 2020 (almost 2 years ago, so it might be slightly different to yours inside), you can see the boiler with the thermosyphon pipes marked with Red and Blue arrows. The brew system is sealed and heats the group by a continual flow of water. Water enters the group from high up in the boiler (or the top of the boiler), red arrows. it then leaves the group by the smaller bottom pipe (blue arrows) and enters the bottom of the boiler to warm up again.

This continual circulation is what heats the group and keeps it warm…if for any reason, air gets into the sealed brew system and collects in the top of the boiler, this thermosyphon will stall (stop) . As soon as you run the pump the air comes out of the group and the thermosyphon restarts.

Symptoms are a cool group and if a shot is pulled without any portafilter in, a short delay (depending on how much ait gets in) before water starts flowing….the cool group with then suck heat away from the brew boiler as the thermosyphon flows and more water than you think comes into the boiler and depresses the brew temperature temporarily.

You can confirm this easily (unless the air leak is really bad…). When you start the machine in the morning….run the pump until you see water exit the group….then you will find it warms up properly

So you have had the background as to what and why….also how to confirm it…I guess the real question is; why is your machine doing it.

Leaky top E61 brew valve
Loose boiler connection leaking steam, or pipe from boiler leaking
Leaky expansion valve. the little knob thing you can twiddle (make sure the brew pressure is set 7 bar plus.), preferably 8 or 9 bar
Rotary pump machines have a 1 way valve and vibe pump machines usually rely on the vibe pump to prevent backflow. I am pretty sure they added a 1 way valve to puristika just in case (green arrow)

These are the only places air can come in, and o course water out…find that leak and you fix your problem. You next need to check with your retailer if they are happy for you to remove the case….let it warm up, look and listen for any leaking/hissing, or if your portafilter basket is always damp. Take a photo and put it on here for us to have a look at.

Now this next bit is important: There is no middle position for the lever that is meant to do anything, and you absolutely don’t want to use it with a single boiler machine like Puristika. This type of machine has no way of knowing if water is low in the boiler, plus it introduces air in the system, that stuff we were talking about. If one day you forget and leave it in the so called preinfusion (middle position), you stand an excellent chance of a failed heating element on your return, if you are gone long enough….and don’t for a second think the limit stats will always save the heating element….they most likely won’t. This is because it’s not water overtemperature, but the top of the heating element becoming exposed and going bang.

I look forward to hearing the result of your investigations.

MediumRoastSteam

That’s a thermosyphon stall it seems? Used to happen to expobars.

When you start a shot, do you always lift the lever all the way up, and also always pushes the lever all the way down to end a shot?

Puristika

Yes, always

Srv-02

DavecUK

Hi Dave … I got the same problem as OP.

I read your thermosyphon stall explanation and it makes sense, that somewhere air is being introduced into the circle.
I modified my machine and added a pressure profile valve and a group head thermometer / pressure gauge.
From my understanding, it is possible that I didn’t seal them properly and air gets into the system. Is this assumption correct?

I can also take pictures from the inside of my machine if you want them for your archive or something. Just tell me what you need from which angle.

Best regards,
Mike

AlfredB

DavecUK

“Now this next bit is important: There is no middle position for the lever that is meant to do anything, and you absolutely don’t want to use it with a single boiler machine like Puristika. This type of machine has no way of knowing if water is low in the boiler, plus it introduces air in the system, that stuff we were talking about. If one day you forget and leave it in the so called preinfusion (middle position), you stand an excellent chance of a failed heating element on your return, if you are gone long enough….and don’t for a second think the limit stats will always save the heating element….they most likely won’t. This is because it’s not water overtemperature, but the top of the heating element becoming exposed and going bang.”

I am a little confused by this statement, Dave. Do you mean to say that leaving the brew lever in the middle position for any amount of time is dangerous? ECM themselves recommend leaving the brew lever in the middle position for 15-20 seconds when backflushing with chemical:

How about if the machine is off and someone accidentally bumps the brew lever to the middle position? I thought all the valves are closed in the middle position. Perhaps I am wrong. Just trying to understand what would happen.

Thank you!

Puristika

Thank you very much for the explanations, I will contact my retailer and see with them ! And i’ll take a picture of my filter basket tomorrow morning.

DavecUK

Puristika Who is your retailer?

Puristika

cafes pfaff (France)

DavecUK

Puristika I’ve not heard of them, but hopefully you won’t have any problem. ECM do support their dealers well if there are any issues.

Puristika

Hi ! some pictures of my pf this morning after 30 min of heating.

the group was cold once again

MediumRoastSteam

Puristika - the photos show a PF without a basket. I take you leave the PF with a basket in the machine to warm up? And if you did, was the basket damp?

DavecUK

Then it’s probably not leaking from the top group valve. Work through the things 1 step at the time, easiest step first and you will find the problem…but get your retailers blessing before you do!

Puristika

MediumRoastSteam Hi ! This morning, no preheating problem. But we can see moisture at the bottom of my basket

My retailer is closed for holidays until January 3, I’ll keep you informed.

ECMP

Hello ! A new owner of the Puristika! In principle everything is fine (waiting to see without there are no problems of heating the Group) except one but … The minimum pressure that allows me to regulate the machine is 10 bars (with the rotating wheel fully on the left). Can someone tell me if the pressure switch can be adjusted internally to 9 bars?

Thank you very much to everyone for your opinions. If anyone has any questions about the machine, I will be happy to solve it.

DavecUK

ECMP The minimum pressure that allows me to regulate the machine is 10 bars (with the rotating wheel fully on the left). Can someone tell me if the pressure switch can be adjusted internally to 9 bars?

There’s nothing inside, the rotating wheel is the knob on the top right….you say you can only reduce pressure to 10 bars? Is that right, can you make a video, upload to YouTube and link to it here?

ECMP

Okay. I try

ECMP

As can be seen, the regulation of the pressure switch goes from 10 to 14 bars instead of 8.5 to 12 bars. Mmmmm ???. I had a 12 bar bezzera and one of the reasons (among others) why I have changed the machine is to shoot at 9 bars!

DavecUK

Thanks, I am clear now on what is happening.

Inside the expansion valve controlled by that knob is a plunger and spring. There is a screw at the side designed to prevent you screwing it out too far and then water under pressure would exit the valve, as well as some hot water from the boiler once the pump is stopped.

The expansion valve is like this inside.

A is the spring and pad which applies pressure to control the brew pressure. One end of the spring goes into a recess at the end of the knobs shaft.
B 2 O rings to prevent leaking (these will require maintenance over time)
C A rebate, this is to limit the movement open and closed of the expansion valve and to prevent you unscrewing it all the way
D is the screw, that engages with C to limit the movement

The holder for the expansion valve is here, and you can see where screw D goes

You appear to be having problems opening it beyond the point where can can achieve less than 10 bar pressure, which isn’t right. Michael and I the owner of ECM did discuss some changes, but they were around some different issues and not this,

I am wondering is there is an issue with the spring sitting in the end of the valve properly…it may not be in that recess at the end of the stem correctly, if so, this would prevent you getting the pressure lower than 10.

A bit like this on the top drawing, instead of in the recess like the second one.

This is the screw in place and there is a little seal. I modified mine (which you must not do), so my screw does not engage in that rebate and I can actually screw the valve out of the front of the machine for lubrication and maintenance. To check your valve you will have to undo that Allen screw, remove the valve from the front. Then reassemble making sure the spring sits in the hole of the stem correctly and see if this fixes the problem.

Or go back to your retailer about the issue, unless you feel confident attempting this.

Please note: These images are from a prototype I had around 2 years ago!

I noticed you posted the same question on CFUK, I would appreciate you don’t repost this stuff on there, or Verticalscope will try and claim ownership of my information. Which I wouldn’t want monetised by them.

ECMP

Okay. I understand the problem and the possible solution. If my seller gives me ok … I will try to fix it myself. Thank you very much for the complete explanation. You are very kind. In a few days I will tell you how the arrangement has gone.

Happy New Year and thank you very much again!

ECMP

One last question! Would it be bad for the machine if, being completely off, it opens and closes the pressure switch completely several times to see if the spring with the movement is positioned by itself?

DavecUK

ECMP One last question! Would it be bad for the machine if, being completely off, it opens and closes the pressure switch completely several times to see if the spring with the movement is positioned by itself?

you can try unscrewing and screwing in the knob, but I’m not sure it will fix anything. Removal of the insides allows you to check if there is any other problem, like a blockage or something, using a torch. At least if you remove it and put it back you will know it is in correctly.

Take photos so I can clearly see the valve and parts!!!

ECMP

“I noticed you posted the same question on CFUK, I would appreciate you don’t repost this stuff on there, or Verticalscope will try and claim ownership of my information. Which I wouldn’t want monetised by them.”

Ok. I will only focus on this forum !