E61 grouphead from Isomac Millenium doesn't pre-heat

#1: Post by **liechtjc** » March 29th, 2014, 12:01 pm

Hello,

I own an Isomac Millenium since 2006. Recently as the head and the boiler were leaking, I perform a full descaling and change the brewer and preinfusion valves in the head... Now everything is perfectly tight but the head is not heating unless I pour a lot of water through it. The coffee is never hot enough even the pressure in the boiler is 1.3-1.5 bar.

What do I do wrong? How to correct the problem?

Thank you in advance for your help!

JC

#2: Post by **ira** » March 29th, 2014, 1:07 pm

I'm going to reply, because I think I can point you in the right direction, but this is a guess.

Most groups are heated by a thermosyphon, a loop containing hot water one end near the bottom of the boiler and one near the top. Since hot water is lighter water moves slowly through that loop heating the group.

So, the 2 things that likely cause this problem are either an air bubble in the line that keeps the water from circulating or a blockage in the loop from dirt or improper assembly.

Ira

#3: Post by **Randy G.** » March 29th, 2014, 6:07 pm

Remove the top nut. Under that, inside the group, is the Gicleur. it is protected by a filter screen. That is the most likely cause as it can easily trap scale and debirs. For more detailed info see the relevant part of this:

How-To 19 - Overhauling and Lubricating the E-61 Group

#4: Post by **Beenbag** » March 29th, 2014, 6:33 pm

Its important to get any air out of that heating loop.
Just loosening the top "mushroom" nut will probably release the trapped air which normally caused this type of problem.
WARNING !
It needs to be done when the m/c is hot, so be careful and do not remove the nut completely ..just loosen it a little and listen for air being pushed out until only water drips out.

#5: Post by **cannonfodder** » March 30th, 2014, 7:36 pm

Sounds like you have scale in the thermosyphon or debris in there. Could be an air lock as well all of which have been mentioned. Also, if you let it heat and open the steam wand does it pump out steam or steam quick and then go flat. Could be false pressure in the boiler as well.

April 3rd, 2014, 12:54 pm

Thank you for all your inputs. I removed the top nut and checked that the filter screen is clear. I also loosen the top nut while the machine is heating and yes this instantly heat the E61 group.

...But when I switch off the machine and heat it again, the group remains cold. It seems that the water doesn't flow in the thermosyphon but I still can not figure out why...