E61 - Steam coming out of the brew head

Need help with equipment usage or want to share your latest discovery?

Postby mathieuroussel » Apr 19, 2014, 4:10 pm

At the end of last year, I bought a Rocket Evoluzione v2. I descale it every 2-3 months, backflush with clean water every day and backflush with detergent every week. Since last week, when I let the machine on without using it for let's say an hour, there is steam coming out from the brew head when I lift the lever. It takes a couple of seconds before the water comes out.

Anyone knows what might cause this because as I said, when I got the machine, it would not behave like that. The dealer says there's no problem .... doubt it

Thank you

User avatar
Randy G.

Postby Randy G. » Apr 19, 2014, 5:00 pm

Some possibilities to start:
- Leaking seal(s) in group allowing water to slowly escape the HX loop. Water can vaporize so you would not see dripping.
- Slow leak in back of group where thermosyphon pipes connect. Open case and look for scale traces which indicate location of leak. Same where these connect to the boiler.
Espresso! My Espresso!


Postby Espresso_Monkey » Apr 19, 2014, 9:36 pm

I would diagnose this properly ASAP.

I had similar symptom, it was a failed no-return valve. Fortunately my rotary pump (which was running very hot and at risk of being damaged) was okay.

SEE: Normal for rotary pump to be HOT !?


Postby mathieuroussel » Apr 20, 2014, 7:54 am

I opened up my machine and there's no trace of scale or any water leaking. I wrote to Rocket. Waiting for their reply


Postby mathieuroussel » Apr 22, 2014, 6:41 pm

here's the reply I got from Rocket ;

If there is steam coming through the group it maybe that there is some air inside the heat exchanger circuit. Generally this will bleed through as you use the machine.

If you very carefully loosen only the nut on top of the group with a hot machine. USE A TOWEL AS THE WATER WILL BE UNDER PRESSURE AND ONLY LOOSEN THE NUT A HALF TURN OR SO. Once the air bleeds out and only water flows from the top of the group, tighten the nut.

I just tried it. Seems to have fixed the problem.

When I turned on the machine so I could bleed it, as it was warming up, I heard that weird sound; can it be caused by air within the HX circuit ?


Postby mathieuroussel » Apr 26, 2014, 4:50 pm

I still have the same problem. Bleeding the machine fixed it temporarily.After 4-5 shots within a day, I'm back to starting point. When I bleed it, air comes out the top nut of the group (mushroom) for 30-45 sec before it's only water. It makes me think that air comes in the circuit when pulling shots but I don't know how and where.

I'm stuck. Help please

User avatar

Postby erics » Apr 26, 2014, 7:19 pm

I know of NO REASON for a requirement to manually bleed "air" from the E-61 grouphead or any other grouphead for that matter.

Are you drawing water from the reservoir or a nearby water line connection ?

That said, I would simply bleed the machine when cold. As the heat exchanger circuit heats up, the temperature of the water contained therein is raised above the normal boiling point (100 C) but the increase in pressure (just sitting there at idle) prevents any steam formation within the circuit.

What is the maximum reading on your boiler pressure gage when fully warmed up ?

Eric S.
E-mail: erics at erols dot com


Postby mathieuroussel » Apr 26, 2014, 8:10 pm

The machine runs on reservoir

Boiler pressure is 1.2 bar

User avatar

Postby erics » Apr 26, 2014, 9:04 pm

I understand what the capabilities of the Rocket Evo line are but am not familiar with their exact hydraulics.

Since you are drawing water from the reservoir, I would cap off the mains water line connection via any convenient means. The connection is likely 1/4" or 3/8" male BSPP threading but you may be able to find a suitable cap or plug (metal or rubber) at a hardware store. If the problem is solved by doing this, the solenoid valve which allows the pump to take suction from line pressure has a "problem".

Have you disassembled the mushroom to see the effects of your frequent descaling?

Eric S.
E-mail: erics at erols dot com


Postby mathieuroussel » Apr 27, 2014, 7:56 am

No since the machine is still under warranty, I don't want to play much with it.I think my problem might be related to the no-return valve.


Since I can't find an easy way to fix this, I'll send the machine back to the dealer.