La Marzocco GS3 leaking water from the boiler

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

#1: Post by cgs »

Hello All,

I am new to the site but not new to espresso.

I have 2x GS3s, both with the mechanical paddle; one is 10 years old and the other about 5, in different locations. I have rebuilt the brew groups a number of times, so reasonably familiar with the machine.

My older machine suddenly developed problems I have not seen before: first, I was getting very little water flow through the brew head.
I contacted my dealer who is too far away to be easily reached physically, and first did the following at their suggestion:
- Disassembled the brew head and cleared the gigleur, which was indeed blocked.

Upon reassembly, the water flow issue was solved, but another problem arose: with 25psi of water to the machine, water started leaking into the drip tray from the boiler overflow (?) exhaust, under the left side of the machine.

Again, at the suggestion of my dealer, I did the following in this order:
1. Back-washed the machine thoroughly,
2. Replaced the O-ring at the exit of the coffee boiler on the top middle rear of the boiler which is connected to an overflow tube going into the drip tray
3. Re-built the entire group with the official re-build kit from La Marzocco
4. Removed and cleaned the expansion valve, drained the coffee boiler and re-set the boiler pressure.

All of this took several days (waiting for parts etc.) but none of this was successful in containing the dripping. At each step, the leak persisted, or even increased.

I am quite positive that I have done each step meticulously, but feel the instructions I have received have missed some fairly obvious step.
I have looked at every diagram I can find, trying to follow the water flow getting into the drip tray. I now wonder if some solenoid is stuck somewhere in the system.

I am now desperate, having been without proper espresso for more than a week!

Does this ring a bell with any of the espresso experts subscribing to this forum? I would be mighty appreciative for any tips!


#2: Post by mariowar »

Have you tried contacting the amazing La Marzocco USA? They will troubleshoot with you an give you advice on how to fix it even if it is out of warranty. They will surely go above and beyond as usual.

ECM Manufacture: @ecmespresso #weliveespresso
Sponsored by ECM Manufacture
cgs (original poster)

#3: Post by cgs (original poster) »

Thanks for this Mario. I did make contact with LM and they are helping me. Seems the advice I got from my dealer missed an obvious step. I think I am on the right track now, and you are right: LM are very responsive!