Rocket Giotto Premium Plus - Very long time before water comes out of grouphead

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by orbarya »

Hi all,

I have an old Rocket Premium Plus Giotto HX machine. I have a thermometer on the group head and only one pressure gauge in the boiler.
I see several issues with it currently and would love to repair it myself with your help:

1. After sitting idle for hours the water temperature at the group head is very low, about 50°c, and then if I flush some water it will rise and get up to 110°c.
2. Also after such long idle time it takes the water very long time until it starts to come out of the group head.
3. When flushing with a blind filter basket there are leaks from all sides of the portafilter.
4. There seems to be excessive dripping from the drain several minutes after pulling a shot, but it eventually stops.

I can post pictures or more information as needed.

thanks for any help, it would be very much appreciated,


#2: Post by DeGaulle »

Seems to me that somewhere there is a leak in the brew path. As a result, no pressure builds as the machine heats up and remains idle, a vapor lock develops, which stalls the thermosyphon hot water circulation and the group cools down.

Item 3 suggests you need a new group gasket.

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#3: Post by HB »

From I have a Quickmill Anita which has a hot water delay from the E61 grouphead:
HB wrote:More than likely it's a thermosyphon stall, as explained in Randy's Understanding and Preventing Thermosyphon Stall. TL;DR: That's when an air pocket forms in the thermosyphon loop due to a tiny leak. If that's the cause, the likely culprits are the expansion valve or the upper seal in the E61 group.
Dan Kehn


#4: Post by JRising »

Items 1 and 2 suggest your brew circuit leaks and loses its water...
item 4 suggests it's leaking over the brew valve.

Replace your group gasket and all 3 of your E61 valves.


#5: Post by DeGaulle »


orbarya (original poster)

#6: Post by orbarya (original poster) »

thank you all for your help!
DeGaulle wrote:no pressure builds as the machine
just wanted to add that the pressure in the boiler looks good according to the pressure gauge, not sure if you are talking about pressure in the boiler or in another place.
HB wrote:the likely culprits are the expansion valve or the upper seal in the E61 group
I followed both links, still not sure about what is the "expansion valve",
the second link talks about the "upper valve gasket - part number 519545", is that the same as what you wrote "upper seal in the E61 group"?
JRising wrote:Replace your group gasket and all 3 of your E61 valves.
Again, not sure what is the group gasket.

I would really really appreciate it if someone can summarize for me all parts I should replace with exact part numbers and a good place to order all of the parts :D
I'm gonna ship the parts internationally and the shipping itself will probably cost quite a lot so I'd rather have everything that I need and not have to order another shipment again...

orbarya (original poster)

#7: Post by orbarya (original poster) »

Hello again,

Sorry to revive this old topic but I still need help as I didn't order any parts yet. I'm thinking of ordering from the following items:

4. E61 GROUP SPRING KIT looks like it contains all the springs related to each of the valves

can anyone please advise if these parts will fit my Rocket Giotto Premium Plus? and should I order anything else while I'm at it?

thank you for any help!


#8: Post by JRising »

In my opinion, without feeling how your lever moves, you probably don't need the springs but it certainly won't hurt to replace them. And yes. You want the three valves mentioned.
The group gasket is the black rubber gasket around the outside of the showerface filter where the brew water comes out of the head into the portafilter. It seals between the portafilter basket and the machine. You'll want an 8.5mm E61 group gasket.

orbarya (original poster)

#9: Post by orbarya (original poster) »

Thanks alot! now I know at least what parts I need.

The lever squeaks and is difficult to move so will replacing the spring help that?

And while I'm at it, is there anything else I should probably replace while taking apart the group head? or at least some other spare parts I should order in the same order? because I'll be shipping it abroad and the shipping will be quite expensive.

thanks again

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Team HB

#10: Post by Jeff »

If you're taking it apart, I'd also replace:

* Mushroom upper cap gasket (smaller, often PTFE)
* Mushroom cap gasket (larger, often PTFE)
* Mushroom o-ring
* Two packing washers on the lever shaft
* The gasket inside of the lever assembly (often PTFE and often the same as the larger, cap gasket)
* Exhaust snout gasket (often PTFE and the same as the larger, cap gasket)
* Exhaust outlet gasket (often PTFE, medium size)

I usually order a couple extra of the mushroom gaskets, as they may not seal up well if you remove the mushroom to check for scale.

If you don't already have Molykote 111 (or equivalent), you'll need a few dabs of that as well.

I have a preference for the Cafelat silicone group gaskets over the hard-rubber, OEM style ones