Help Please: Krups EA8250 Leaking

[ShadowRegent]

I have a Krups EA8250 that has started to leak. This isn't the first time it has developed a leak-- a few months ago, the upper piston seal was worn and was leaking coffee. After replacing that, things were good for a few months, but there is now a small leak of cold water under the unit occasionally after either turning the unit on or brewing.

Before disassembling the unit to get a closer look, I was wondering what might be a likely cause. I see that there's also a boiler seal (MS-5015004), but was unsure if a leak there would be water or espresso.

Thanks in advance for any advice or suggestions!