
Originally Posted by
Sir
Hey esendee,
The BZ99 does have 2 solenoids, a 2-way for boiler fill and a 3-way for brewing.
From what you've described, it sounds like the boiler overfilling is happening when you try to run water from the group which indicates that water that should be going through the HX system is leaking into the boiler. If that's the case, you likely either have the boiler fill solenoid not closing properly, either from some grit in the valve, which could be cleaned out if you pull apart the valve, or the seal in the valve is worn, in which case you'd need to replace the valve. The other potential cause is a crack in the HX pipe, causing water to leak into the boiler when you brew.