Isomac portafilter not venting pressure

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WouterB

#1: Post by WouterB »

Hi all,
I am new to this site but as I am having a problem with my machine i am hoping someone can assist.

I have a Isomac la mondiale purchase in 2010 in perth from Espresso italia in North Perth.
I have done all the repairs on my machine over the last 6 years as I am an electrical contractor with some back ground in fault finding, if I had taken my machine in for repairs when needed, then the cost would have been more than the purchase price, and I would have replaced it with something else.

I recently replaced the water tank fill solenoid assembly as it failed and wouldn't fill the tank, plus I replaced the dual pressure gauge as it seemed to be stuck on one reading, since this last repair the following fault occurs.

The machine delivers the espresso shot ok except when I stop the shot it used to vent some pressure from a drain near the tray, this no longer happens as the portafilter seems to still have pressure in it after the shot is finished pouring, plus instead of venting pressure in the form of steam from the lower drain some water comes out, but pressure still remains in the portafilter ?

I have emailed isomac in italy but as yet they haven't replied, not so sure about their grasp of english or their attitude to answering fault questions online.

It may be not related to my recent repair but I cant work out whats wrong, if I wait about 3 or 4 minutes after the shot has finished pouring then the pressure is gone.

thank you in advance
WouterB

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drgary
Team HB

#2: Post by drgary »

Usually a three way valve releases the pressure in the brew path. Did you do your repair with stock parts? Added: Wrong direction. See Alan Frew and Dan Kehn's suggestion below to inspect and/or rebuild the e61 group.
Gary
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WouterB (original poster)

#3: Post by WouterB (original poster) »

Hi,

thank you for your reply...
Yes I used parts sourced from five senses ( https://www.fivesenses.com.au/ )

So how does the 3 way valve allow flow ...I assume one way is flow from pump to the portafilter and then after shot is complete flow from the portafilter to waste ?

something must control which way flow is allowed...or is it like a non return valve ?

I replaced item 41 and item 29 in the following image, can you identify which item may be the 3 way valve ?

https://www.espressocare.com/assets/upl ... mplete.pdf

WouterB (original poster)

#4: Post by WouterB (original poster) »

Hi,
I think you are right as I found this description for the isomac la mondiale:
Three-way mechanical solenoid valve allows water pressure in group head to evacuate to drip tray once the coffee extraction process is completed, and it allows proper back-flushing of group head for cleaning.
except I can't locate it unless that's the actual valve that I changed but it only has two pipe connections on it which I assume is either open or closed depending on the electrical coil state...power on ..valve open or power off ..valve closed ?

Alan Frew

#5: Post by Alan Frew »

It's an E-61 analogue group. The only solenoid that matters in your machine is the boiler fill one, and it doesn't affect your problem. You need to replace the cams, washers and maybe the springs and do a decent whole group clean, descale and backflush. See http://www.coffeeparts.com.au/parts-by- ... r-operated for the 3 cam/washer parts groups involved.

Alan

User avatar
HB
Admin

#6: Post by HB »

WouterB wrote:The machine delivers the espresso shot ok except when I stop the shot it used to vent some pressure from a drain near the tray, this no longer happens as the portafilter seems to still have pressure in it after the shot is finished pouring...
Review the operation described in Internals of an E61 Brew Head and the cause may be more evident. It sounds like one or both of the lower two valves aren't opening; that typically happens because the stem or cam is worn down. See E61 Group Servicing and Overhauling and Lubricating the E-61 Group for detailed repair instructions.
Dan Kehn

WouterB (original poster)

#7: Post by WouterB (original poster) »

Hi,
thanks for your replies, after opening up the e61 group head it all makes sense now, the group head is the mechanical 3 way valve, I found the stem that the cam rubs on to open the exhaust is worn out and is now too short to open the exhaust valves, I will source replacement parts and service the group head, I guess 6 years of making coffee has worn out the brass parts, cant complain.

cheers