The Rocket Vacuum Breaker Valve is an internal replacement part that technicians use for repair based on the diagnosis of the espresso machine. If the boiler is part of the problem this is a part that sometimes can be rinsed and re-used or replaced.
Best Answer:Yes, this would fit the Cellini. While we likely have the part that would fit, you could give us a call to check, but we would need the part number to find out if we have it available. The o-ring is something that will wear over time, so it doesn't surprise me that you're wanting to replace it. However, the o-ring, while it might be a little less expensive, will be much more difficult to replace than just replacing the vacuum breaker valve. I would suggest just replacing the whole valve, and saving yourself some headache and potential frustration should the o-ring break or become damaged while you're trying to install it. :-)